Assessing Hydraulic Conditions Through Francis Turbines Using an Autonomous Sensor Device

Renewable Energy 99 (2016) 1244e1252

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Renewable Energy

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Assessing hydraulic conditions through Francis turbines using an autonomous sensor device

* Tao Fu, Zhiqun Daniel Deng , Joanne P. Duncan, Daqing Zhou, Thomas J. Carlson, Gary E. Johnson, Hongfei Hou

Paciﬁc Northwest National Laboratory, Energy & Environment Directorate, Richland, WA 99352, United States article info abstract

Article history: Fish can be injured or killed during turbine passage. This paper reports the first in-situ evaluation of Received 6 February 2016 hydraulic conditions that fish experienced during passage through Francis turbines using an autonomous Accepted 9 August 2016 sensor device at Arrowrock, Cougar, and Detroit Dams. Among different turbine passage regions, most of Available online 19 August 2016 the severe events occurred in the stay vane/wicket gate and the runner regions. In the stay vane/wicket gate region, almost all severe events were collisions. In the runner region, both severe collisions and Keywords: severe shear events occurred. At Cougar Dam, at least 50% fewer releases experienced severe collisions in Francis turbine the runner region operating at peak efficiency than at the minimum and maximum opening, indicating Turbine evaluation Fish-friendly turbine the wicket gate opening could affect hydraulic conditions in the runner region. A higher percentage of Turbine passage releases experienced severe events in the runner region when passing through the Francis turbines than Turbine operations through an advanced hydropower Kaplan turbine (AHT) at Wanapum Dam. The nadir pressures of the three Francis turbines were more than 50% lower than those of the AHT. The three Francis turbines had much higher magnitudes and rates of pressure change than the AHT. This study provides critical information on hydraulic conditions and fish passage information of Francis turbines, which can help guide future laboratory studies of fish passing through Francis turbine, design fish-friendly turbines, and optimize the operation of existing turbines for better fish passage conditions. © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction up to several hundred meters depending on hydraulic turbine type. Fish can often pass through a turbine runner in less than a second. Hydropower is an important renewable energy source [1]. The absolute pressure on the downstream side of the turbine blade However, hydropower projects can also pose negative environ- can be less than the atmospheric pressure. The consequence of fish mental impacts because downstream migrating fish can be injured being exposed to this rapid and sometimes extreme pressure or killed when they pass through turbine passages due to the severe change has been studied extensively and categorized as baro- hydraulic conditions. It is critical to understand the hydraulic trauma injury [3e8]. Early studies [4,9e12] found that pyhsosto- conditions and physical stresses to which fish are exposed when mous fish, which have swim bladders, can endure high magnitudes they pass through hydraulic turbines so that fish friendly turbines of pressure without being injured or killed because of their ability can be designed and turbine operations can be guided to mitigate to adjust their swim bladder by ingesting or venting gas through the impacts [2]. the mouth and pneumatic duct. However, the decompression Injuries and mortalities of turbine-passed fish can result from process that occurs when fish pass through turbine runners can several mechanisms [2]: rapid and extreme pressure changes, cause fish mortality (i.e., barotrauma). These studies have found cavitation, shear stress, turbulence, strike, and grinding. Rapid that barotrauma injuries can be related to the ratio of exposure pressure change happens when fish pass through a turbine runner. pressure to acclimation pressure (Pe/Pa). Fish mortalities were The absolute pressure head upstream of a turbine blade can be to observed mostly when Pe/Pa was less than 0.4 and little or no mortality was observed when Pe/Pa was larger than 0.6. Abernethy and Becker [13] used a series of pressure testing devices to expose several fish species (Bluejill, Fall chinook salmon, and rainbow * Corresponding author. trout) to realistic pressure-time profiles associated with turbine E-mail address: [email protected] (Z.D. Deng). http://dx.doi.org/10.1016/j.renene.2016.08.029 0960-1481/© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). T. Fu et al. / Renewable Energy 99 (2016) 1244e1252 1245 passage; they found different mortality rates when fish were and the diameter was 800 mm. The rotational speed was 250 rpm. acclimated to different depths and exposed to different total dis- At HEP2, one Kaplan turbine was installed. The runner had four solved gas levels and nadir pressures. Recently, Brown et al. [8] blades and the diameter was 2100 mm with a rotational speed of conducted extensive experiments using an advanced turbine 333 rpm. Their study found the mortality rates of the smolts pressure simulation system [14] and identified that the ratio of fish passing through the Francis turbines were consistently higher than acclimation depth to nadir pressure was the most predictive vari- those of the fish passing through the Kaplan turbine: 38% vs. 9% in able for estimating the probability of mortal injury of juvenile 2004 and 33% vs. 13% in 2005. Chinook salmon. Cavitation happens when water pressure is at or Although fish injury mechanisms during turbine passages were below vapor pressure and gas bubbles form in the water [10,15]. studied extensively, the leading mechanism/mechanisms that Studies have suggested that the collapse of gas bubbles can create cause fish injuries can vary at different dams due to different tur- violent shock waves and nearby fish could get injured [10,12]. Shear bine passage configurations. While the live fish field studies pro- stress happens when forces are applied parallel to the fish body. vided the overall turbine biological performance, they do not Laboratory studies have shown that shear flow can cause different provide enough information to understand what hydraulic condi- fish injuries [16,17]. Shear stress can be near the stay vanes, wicket tions and physical stresses caused the mortality and injury, espe- gates, runner and draft tube [18]. Different scales of turbulence cially where mortality and injury occurred. To better understand occur throughout a turbine passage. Small-scale turbulence, such as these questions, an autonomous sensor device (Sensor Fish) was local eddies, may distort and compress part of the fish body and developed [30,31]. Sensor Fish can be released into operating tur- cause localized fish injuries. Large-scale turbulence, such as bines independently or concurrently with live fish to measure in- vortices in the draft tube (swirl), can disorient fish and make them situ hydraulic conditions. Sensor Fish measurements can help re- to be more susceptible to predators in the tailrace [2]. Strike hap- searchers understand the fish injury mechanisms in each passage pens when fish collide with turbine passage structures such as stay region, guide future laboratory studies of fish passing through vanes, wicket gates, turbine runner hub/blades, and draft tube Francis turbine, design fish-friendly turbines, and optimize the walls. Several blade-strike models were developed to predict fish operation of existing turbines for better fish passage conditions. mortality due to turbine runner blades [10,19e23]. Grinding hap- This study evaluated the hydraulic conditions within Francis tur- pens when fish squeeze through narrow opening of clearances bines using Sensor Fish at three different dams: Arrowrock Dam, between structures in a turbine passage [2]. Fish grinding injuries Cougar Dam, and Detroit Dam. Severe hydraulic conditions are usually localized bruises, but they can also be deep cuts or even including collision and shear events in each region of a turbine decapitation. passage were quantified. Nadir pressure, pressure change, and the Francis turbines and Kaplan turbines are the two most common rate of pressure change in the turbine runner region were also turbine types. Francis turbines are usually installed in storage estimated. The results were then compared with the Sensor Fish projects with a normal head range of 30e550 m, while Kaplan results from the AHT Kaplan turbine at the Wanapum Dam and the turbines are usually installed on run-of-river projects and head concurrent live fish results. ranges from 1.5 to 80 m [24]. Francis turbines usually have more runner blades (9e25) than Kaplan turbines (3e8). The flow in the 2. Methods runner region is also different: water enters Francis turbine runners in the radial direction and exits in axial directions; water enters and 2.1. Test sites exits the Kaplan turbines in the axial direction at both inlet and outlet at the turbine runner. The engineering difference between Arrowrock Dam is located on the Boise River approximately these two turbine types could lead to different physical conditions 35.4 km upstream from Boise, Idaho. It is a 108 m tall concrete for passing fish. Mortality rates of fish passing through Francis thick-arch dam consisting of 10 clamshell valve conduits and a turbines are quite variable and frequently greater than those of fish power plant with two Francis turbine units. Each turbine has 24 passing through Kaplan turbines [25]. Kaplan turbines with an wicket gates and the capacity is 7.5 MW. The turbine runner is adjustable blade propeller can have a fish survival rate from 85 to 1.72 m in diameter with 13 blades. The penstock of each turbine 96% [26]. For Francis turbines, Eicher [27] reviewed 22 previous unit ties into one of the clamshell valve conduits. studies and found the reported fish mortality ranging from 5% to Cougar Dam is a 138 m tall rock fill dam located on the South 50%. Eicher's review also found a significant relationship between Fork of the McKenzie River in Oregon. It consists of two regulating peripheral runner velocity and mortality of salmonids for Francis outlets and one powerhouse with two Francis turbine units. The turbines and higher peripheral runner velocity would lead to capacity of each turbine unit is 12.5 MW. Each unit has 24 wicket higher mortality. Recent field studies showed the mortality could gates and the turbine diameter is 1.83 m with 13 blades. be relatively high when fish pass Francis turbines. For example, a 2- Detroit Dam is located at river 78.9 km on the North Santiam year study by Serrano et al. [28] used both acoustic and radio River in Oregon. It is a concrete dam with a 6-bay spillway, two telemetry to track Atlantic salmon smolts at Testebo River, Sweden. regulating outlets and one powerhouse with two Francis turbine They released 24 and 34 radioetagged fish with mean body length units. Each turbine unit has 24 wicket gates and the capacity is of 223 mm and 214 mm in 2006 and 2007, respectively. The fish 50 MW. Each turbine runner is 3.30 m in diameter with 13 blades. were released approximately 3.1 km upstream of the power station, which contains two Francis turbine units with a discharge capacity 2.2. Sensor Fish of 10 m3/s. The study found five fish in 2006 and 12 fish in 2007 entered into turbine units and the turbine mortality was 60% and The Sensor Fish (Fig. 1) is an autonomous sensor package to 75% for the two years, respectively. Calles et al. [29] studied the study the physical conditions of hydraulic turbine, spillway and migrating behavior of brown trout in Eman River, Sweden in 2004 other hydraulic structure passages [30]. It is 24.5 mm in diameter and 2005 using Passive Integrated Transponder and radio telem- and 90.0 mm in length. The weight of the Sensor Fish is 43 g and it etry. Downstream migrating smolts were observed at two low head is neutrally buoyant in fresh water. At the sampling rate of 2000 Hz, power plants (8.7 m head at HEP2 and 5.5 m head at HEP3). HEP3 the Sensor Fish measures linear accelerations and angular velocities was located 800 m upstream of HEP2 with two twin-Francis tur- in three dimensions, pressure, and temperature. Before the bine units and four runners installed. Each runner had 16 blades deployment, each Sensor Fish device was calibrated and evaluated 1246 T. Fu et al. / Renewable Energy 99 (2016) 1244e1252

0.0075 s and a shear event has peak duration longer than 0.0075 s, where peak duration of acceleration is defined as the duration within 70% of the peak value of a high amplitude impulse acceleration. Similar to Kaplan turbines, the largest pressure rate of change also occurs when fish passes through the Francis turbine runner to reach the underside (or suction side) of the turbine blades. Median nadir pressure, average magnitude of pressure change and pressure rate of change between entering the runner region and the nadir pressure point were computed for each treatment. The results were then compared to similar measurements reported for an advanced hydropower Kaplan turbine (AHT) at Wanapum Dam that included features to improve survival for fish passage [32]. Although the flow and power generation of the AHT differ from those of the Francis turbines, a qualitative comparison of the Sensor Fish data high- lights areas for fish passage improvements.

3. Results and discussion Fig. 1. Sensor Fish device. Drawing shows the measurement axes for the three components of linear acceleration (up-down, forward-back, and side to side) and three 3.1. Francis turbine passage examples components of angular velocities (pitch, roll, and yaw). Fig. 2 shows a typical example of the pressure and acceleration measurements at Arrowrock Dam. Fig. 2 (a) and (c) were from individually. Sensor Fish F908 and Fig. 2 (b) and (d) were from Sensor Fish F664. The top two panels (a) and (b) showed the overall measurements 2.3. Study design from the Sensor Fish release to the turbine draft tube exit. The bottom two panels (c) and (d) showed the detailed Sensor Fish At Arrowrock Dam, turbine Unit 1 was chosen for the Sensor measurements in the stay vane/wicket gate region and the turbine 3 Fish study. The turbine discharge during the study was 22.65 m /s runner region. In (a) and (b), Tr is the time when the Sensor Fish and the wicket gate opening was at 80%. Eleven Sensor Fish were entered the forebay; T1 is the time when the Sensor Fish left the released in the dam forebay before the clamshell value conduit clamshell value conduit entering the turbine penstock; T5 is the entrance. Five valid datasets were collected. time when the Sensor Fish reached tailrace water surface. In (c) and At Cougar Dam, three treatments were evaluated at turbine Unit (d), T2 is the time when the Sensor Fish entered into the stay vane 2 for different turbine operation conditions: minimum wicket gate from scroll case; T3 is the time when the Sensor Fish entered the fi opening, maximum wicket gate opening, and peak ef ciency turbine runner from wicket gate exit; T4 is the time when the operation. The corresponding turbine discharges were 9.63, 15.57, Sensor Fish left the turbine runner entering the turbine draft tube. 3 fi and 12.88 m /s, respectively. The Sensor sh were released at the In the penstock region, both Sensor Fish experienced one severe penstock entrance in the dam forebay. Sixteen Sensor Fish were event (IC_1) and no shear events were observed. In the stay vane/ released at the minimum wicket gate opening condition and four wicket gate region, both Sensor Fish had one slight shear event valid datasets were acquired. Fourteen Sensor Fish were released at right after entering the stay vane (WS_1) and one slight shear event the maximum wicket gate opening condition and three valid right before exiting the wicket gate (WS_2). In the runner region, datasets were collected. Four Sensor Fish were released at the peak both Sensor Fish experienced one median shear event (RS_1) when fi ef ciency condition and all of them were successfully recovered they left the turbine runner entering the draft tube region, which with valid data. was right before they reached the nadir pressure (Pnadir). Sensor At Detroit Dam, 23 Sensor Fish were released through turbine Fish F908 passed both the stay vane/wicket gate region and runner Unit 2 in the dam forebay before the turbine penstock entrance. region without experiencing any severe events, while Sensor Fish Nineteen of them were successfully recovered with valid data. F664 had one severe collision (WC_1) with the wicket gate and one 3 During the test, the turbine discharge was 62.30 m /s. severe collision (RC_1) with the turbine runner. In the draft tube region, no median event or severe event was observed from either 2.4. Data analysis Sensor Fish.

Pressure measurements were used to estimate the location and 3.2. Exposure events that Sensor Fish experienced during Francis passage time of the Sensor Fish, including the injection pipe, the turbine studies turbine penstock region, the stay vane/wicket gate region, the turbine runner region, and the draft tube region. Accelerations In the penstock region, no Sensor Fish experienced severe shear were used to identify Sensor Fish events. When a Sensor Fish has events at any of the three Francis turbines (Table 2). Of the 19 direct contact with passage structures or passes through turbulent Sensor Fish releases at Detroit Dam, three of them experienced shear flows, high amplitude impulse accelerations and rotational severe collisions. At Arrowrock Dam, four of the five Sensor Fish velocities can be recorded. Based on previous laboratory studies releases experienced severe collisions. In all three treatments at [17] and [30], Sensor Fish events are categorized into three levels of Cougar Dam, no Sensor Fish experience any sever events. exposure events using the acceleration magnitude (jaj): (1) severe In the stay vane/wicket gate region, more Sensor Fish experi- event if jaj >¼ 95 g, (2) medium event if 95 g > jaj >¼ 50 g, and (3) enced severe collisions than severe shear events at all sites slight event if 50 g > jaj >¼ 25 g. Each event can also be identified as (Table 2). At Arrowrock Dam, four of the five releases experienced a collision event or a shear event based on the acceleration time severe collisions, while only one Sensor Fish experienced severe duration. A collision event has acceleration peak duration less than shear events. At Detroit Dam, six of 19 releases experienced severe T. Fu et al. / Renewable Energy 99 (2016) 1244e1252 1247

Fig. 2. Pressure profiles and acceleration profiles collected from two Sensor Fish releases at Arrowrock Dam. The left two panels (a) and (c) were from Sensor Fish F908 and the right two panels (b) and (d) were from Sensor Fish F664. The top two panels showed the overall profiles from the Sensor Fish release to the tailrace. The lower two panels were the profiles in the stay vane/wicket gate region and the turbine runner region. collisions and only one Sensor Fish experienced severe shear events. For all three treatments at Cougar Dam, one Sensor Fish experienced severe collisions in each treatment and no Sensor Fish experienced severe shear events. In the runner region, except for two Sensor Fish at Arrowrock Dam, all Sensor Fish experienced either severe collisions or severe shear events or both. In Detroit Dam study, all 19 Sensor Fish experienced severe shear events and eight of them experienced severe collisions. At Arrowrock Dam, three Sensor Fish experienced severe collisions and one of them experienced severe shear events. For the three treatments at Cougar Dam, all Sensor Fish experienced severe shear events. One Sensor Fish experienced severe collisions under the peak efficiency condition, while three Sensor Fish experienced severe collisions under the minimum opening condition and the maximum opening condition. In the draft tube region, two Sensor Fish experienced severe collisions and one of them had severe shear events at Detroit Dam. Only one Sensor Fish experienced severe event at Cougar Dam and Fig. 3. Velocity triangles of Francis Turbines at turbine runner blade inlet and outlet under different operation conditions: (a) maximum wicket gate opening condition; (b) it was a collision under the minimum opening condition. There was peak efficiency condition; (c) minimum wicket gate opening condition. no severe event at Arrowrock Dam. At Cougar Dam, fewer Sensor Fish experienced severe collisions in the runner region under the peak efficiency condition (1 Sensor efficiency condition; and (c) minimum wicket gate opening con- Fish) than under the minimum opening condition and the dition. In the velocity triangles at turbine inlet, V1 is the absolute maximum opening condition (3 Sensor Fish under each condition), flow velocity entering the turbine runner. V1 has two components: fl indicating better ow condition in the turbine runner region under U1 and Vr1, where U1 is the peripheral velocity at blade entrance, fi the peak ef ciency condition compared to the other two condi- and Vr1 is the relative velocity with respect to the runner blade. tions. Fig. 3 shows the velocity triangles of Francis turbines at the Under both the maximum opening condition (Fig. 3a) and the turbine runner inlet and outlet under different operation condi- minimum opening condition (Fig. 3c), the direction of Vr1 is not tions: (a) maximum wicket gate opening condition; (b) peak tangential to the runner blade and consists two components: Vb 1248 T. Fu et al. / Renewable Energy 99 (2016) 1244e1252 and Vw1, where Vb is in the tangential direction to the runner blade are very close (1.71 m vs. 1.83 m); they have the same number of tip and Vw1 is the same direction as the peripheral velocity of the wicket gates (24); and the wicket gate heights B1 are close too turbine blade. The existing of extra peripheral velocity component (0.39 m and 0.41 m). Another possible factor might be the flow (Vw1 in Fig. 3c) and the less peripheral velocity component (Vw1 in velocity entering the wicket gate gaps. The discharge was almost Fig 3a) could cause swirls or flow separations and result in turbu- twice at Arrowrock Dam than at Cougar Dam peak efficiency con- lent flows at turbine runner inlet. While under the peak efficiency dition (22.65 m3/s vs. 12.88 m3/s). When water was distributed condition (Fig. 3b), Vr1 is designed to be in the tangential direction uniformly along the outer circumference of the stay vane ring by to the runner blade tip [24], which creates a shock-free entry to the the spiral casing, the flow velocity entering stay vane gaps and runner blade and provides the smoothest possible path for flow to wicket gate gaps was much higher at Arrowrock Dam than at pass the blade. In the velocity triangles at turbine runner outlet, V2 Cougar Dam because of their similar wicket gate geometry. is the absolute flow velocity and has two component: U2 is the peripheral velocity at runner outlet, and Vr2 is the relative velocity 3.3. Comparison of Francis turbine severe events with AHT Kaplan with respect to the runner blade. Under the peak efficiency con- turbine severe events dition (Fig. 3b), the flow direction of V2 is designed to close to axial direction and only has axial component Vf2. Off the peak efficiency The Sensor Fish experienced higher percentage of severe events condition (Fig. 3a and c), V2 has one extra component Vw2 besides at the three Francis turbines than the AHT Kaplan turbine (Table 3). Vf2. The existing of Vw2 could cause swirls when flow entering the Of the 536 releases in the AHT Kaplan turbine study [32],21% draft tube [33,34], which may also result in turbulent flows in the experienced severe collisions and 1% experienced severe shear turbine blade outlet. When Sensor Fish passed the turbine runner events. For the three Francis turbines, all Sensor Fish releases under either the maximum opening condition or the minimum experienced either severe collisions (Arrowrock Dam), or severe opening condition, they may have higher probability of colliding shear events (Detroit Dam, minimum opening condition and peak with runner blades due to the more turbulent flows than under the efficiency condition at Cougar Dam), or both (maximum opening peak efficiency condition. In order to make runner passage more condition at Cougar Dam). In the runner region, fewer Sensor Fish fish friendly for existing turbines, turbine units could be operated at experienced severe shear events than severe collisions in the AHT or around peak efficiency conditions, which can be achieved by Kaplan turbine study (1% vs. 5%). However, all Sensor Fish (100%) distributing power load among several turbine units and avoiding experienced severe shear events at Detroit Dam and Cougar Dam. operating one unit at the maximum wicket gate condition. For In the wicket gate region, more Sensor Fish experienced severe newly designed turbines, variable speed approach could be collisions than severe shear events in the AHT Kaplan turbine study explored. Early study by Frank et al. [26] have showed that the (14% vs. 1%), which was also observed in all Francis Turbine studies combination of variable turbine speed with adjustable wicket gate (80% vs. 20% at Arrowrock Dam, 32% vs. 5% at Detroit Dam, 25% vs. openings could enable turbine units to operate at peak efficiency 0% under minimum opening condition at Cougar Dam, 33% vs. 0% conditions at various heads. In addition, a recent simulation of a under the maximum opening condition at Cougar Dam, and 25% vs. 2 320 MW variable speed pump-turbine power plant presented a 0% under the peak efficiency condition at Cougar Dam). feasible control strategy that can provide high dynamic perfor- The three Francis turbines had higher percentage of severe mance in full compatibility with safety requirements [41]. events, especially severe shear events, in the runner region than the The Sensor Fish experienced more severe collisions than severe AHT Kaplan turbine (Table 3), suggesting that the flow might be shear events in the stay vane/wicket gate region at the three France more turbulent in the Francis turbines than in the AHT Kaplan turbines: 4 severe collisions vs. 1 severe shear events at Arrowrock turbine. Francis turbines and Kaplan turbines have different flow Dam, 6 severe collisions vs. 1 severe shear events at Detroit Dam, patterns in the runner region. In Kaplan turbines, water enters and and 1 severe collisions vs. 0 severe shear events under all three exits the runner region in axial direction with little radial move- operation conditions at Cougar Dam, suggesting that fish mortality ment. In Francis turbines, flow enters the runner bucket in the could be more due to collisions than shear events in the stay vane/ radial direction and exit in axial direction. Having both axial flow wicket gate region. Researchers have found that fish mortality in and radial flow in each runner bucket, flow condition in Francis the wicket gate region is related to the wicket gate clearance and turbines could be more turbulent than in Kaplan turbines. The the narrow clearance between wicket gates can increase the fish geometry difference between the three Francis turbines and the mortality [25,27]. However, the wicket gate clearance alone could AHT Kaplan turbine might also contribute to the higher percentage not explain why Sensor Fish experienced more severe collisions at of Sensor Fish experienced severe collisions when passing three Arrowrock Dam than at Cougar Dam because the two dams have Francis turbine runners than the AHT Kaplan turbine runner. The similar wicket gate geometry (Table 1): their runner diameters D1 three Francis turbines all have much smaller runner diameter D1

Table 1 Physical parameters of the three Francis turbines.

Arrowrock Dam Detroit Dam Cougar Dam

Min opening Max opening Peak efﬁciency

Head (m) 56.08 94.49 88.09 88.09 88.09 Rotational speed (rpm) 300 163.6 400 400 400 Penstock diameter (m) 1.47 3.86 3.20 3.20 3.20 Runner diameter D1 (m) 1.71 3.30 1.83 1.83 1.83 Wicket gate height B1 (m) 0.39 0.54 0.41 0.41 0.41 Runner exit diameter D2 (m) 1.81 3.90 1.95 1.95 1.95 Runner peripheral velocity (m/s) 26.81 28.29 38.30 38.30 38.30 Number of runner blades 13 13 13 13 13 Number of wicket gates 24 24 24 24 24 Unit discharge (m3/s) 22.65 62.30 9.63 15.57 12.88 Penstock average velocity (m/s) 13.29 5.32 2.39 3.87 3.20 T. Fu et al. / Renewable Energy 99 (2016) 1244e1252 1249

Table 2 Number of Sensor Fish that experienced severe events in each passage region.

Passage region Severe event type Arrowrock Dam Detroit Dam Cougar Dam

Minimum opening Maximum opening Peak efﬁciency

Valid releases (N) 5 19 4 3 4 Penstock Collision 4 3 0 0 0 Shear 0 0 0 0 0 Stay vane/wicket gate Collision 4 6 1 1 1 Shear 1 1 0 0 0 Turbine runner Collision 3 8 3 3 1 Shear 1 19 4 3 4 Draft tube Collision 0 2 1 0 0 Shear 0 1 0 0 0 All regions Collision 5 16 3 3 2 Shear 2 19 4 3 4

Table 3 Percentage of the Sensor Fish that experienced severe collisions and severe shear events. The Sensor Fish data at Wanapum Dam are from Deng et al. ([31]).

Passage region Severe event type Arrowrock Dam (%) Detroit Dam (%) Cougar Dam Wanapum Dam (%)

Minimum opening (%) Maximum opening (%) Peak efﬁciency (%)

Penstock Collision 80 16 0 0 0 0 Shear 0 0 0 0 0 0 Stay vane/wicket gate Collision 80 32 25 33 25 14 Shear 20 5 0 0 0 1 Turbine runner Collision 60 42 75 100 25 5 Shear 20 100 100 100 100 1 Draft tube Collision 0 11 25 0 0 3 Shear 0 5 0 0 0 0 All regions Collision 100 84 75 100 50 21 Shear 40 100 100 100 100 1

(1.71 m at Arrowrock Dam, 3.3 m at Detroit Dam, and 1.83 m at Cougar Dam) (Table 1) than the AHT Kaplan turbine diameter (7.75 m). The 13 blades in each of three Francis turbines divided the runner bucket into much smaller space than the six blades in the AHT Kaplan turbine. The rotational speed of the three Francis turbine runners (300 rpm at Arrowrock Dam, 164 rpm at Detroit Dam, and 400 rpm at Cougar Dam) were also higher than that of the AHT Kaplan turbine runner (86 rpm). Therefore, when the Sensor Fish enter the turbine runner region, they have higher possibility of colliding with the leading edge of the runner blade in the three Francis turbine runners than the AHT Kaplan turbine runner.

3.4. Pressure

All measured nadir pressures were below the barometric pressure (101.3 kPa) in the three Francis turbines (Fig. 4). A minimum median nadir pressure of 24 kPa was observed under the maximum opening condition at Cougar Dam. Compared with the results of the AHT Kaplan turbine at Wanapum Dam [32], which had median nadir pressures above the barometric pressure, the median nadir pressure of the three Francis turbines were lower than the AHT Fig. 4. Median and range of the lowest pressure (nadir) that the Sensor Fish experi- Kaplan turbine. The range of nadir pressure was from 6 kPa to enced in each study. The Sensor Fish data at Wanapum Dam are from Deng et al. ([31]). 71 kPa for the three Francis turbines, while the range was from 42 kPa to 189 kPa for AHT Kaplan turbine. AHT Kaplan turbine has the trend that nadir pressure decreases when turbine discharge Wanapum Dam (295 kPa) (Table 4). However, the rate of pressure increases [32]. This trend was not observed from the three different change at Arrowrock Dam (4661 kPa/s) was almost four times the wicket gate opening treatments at Cougar Dam, where higher nadir maximum rate of pressure change of the AHT Kaplan turbine at pressures in terms of median, minimum, and maximum were Wanapum Dam (1180 kPa/s). Both the magnitude and the rate of observed under the peak efﬁciency condition than the minimum pressure change were also much higher at Detroit Dam and Cougar opening condition and the maximum opening condition. Dam than the AHT Kaplan turbine. The trend that rate of pressure The average magnitude of pressure change from the turbine change increases when the discharge increases, which was wicket gate through the runner exit at Arrowrock Dam (283 kPa) observed in the AHT Kaplan turbine study [32], was also observed was close to the highest in the AHT Kaplan turbine study at 1250 T. Fu et al. / Renewable Energy 99 (2016) 1244e1252

Table 4 Average magnitude of pressure change, rate of pressure change, and passage time during transit of the sensor from wicket gate passage to exit from the turbine runner in each study. The Sensor Fish data at Wanapum Dam are from Deng et al. ([31]).

Arrowrock Dam Detroit Dam Cougar Dam Wanapum Dam

Min opening Max opening Peak efﬁciency 255 m3/s 311 m3/s 425 m3/s 481 m3/s 524 m3/s

Pressure Change (kPa) 283 860 787 848 784 253 254 270 283 295 Pressure ROC (kPa/s) 4661 7670 7769 13,215 9300 490 605 860 1020 1180 Time passing turbine runner (s) 0.090 0.174 0.152 0.085 0.173 0.377 0.407 0.436 0.558 0.289

from the three different wicket gate opening studies at Cougar lowest survival rate of 11.1% (SE ± 6.1%) at Arrowrock Dam and the Dam: the rate of pressure change was 7769 kPa/s under the mini- highest survival rate of 54.1% (SE ± 3.8%) at Detroit Dam. All Sensor mum opening condition, 9300 kPa/s under the peak efficiency Fish experienced either severe collisions or severe shear events or condition, and 13,215 kPa/s under the maximum opening condition both during the turbine passage. Among the three wicket gate at Cougar Dam. The average time that the Sensor Fish passed the opening conditions at Cougar Dam, lower percentage of Sensor Fish three Francis turbines was also less than passing the AHT Kaplan experienced severe collisions under the peak efficiency condition turbine. For the three Francis turbines, the Sensor Fish passed the (50%) than the minimum wicket gate opening condition (75%) and turbine runner in less than 0.174 s on average; For the AHT Kaplan the maximum wicket gate opening condition (100%). However, the turbine, the average time ranged from 0.289 s to 0.436 s depending live fish results showed that the 48-h survival rate at peak effi- on turbine discharge. ciency condition (37.1%) was not higher than at the maximum Nadir pressure, pressure change and rate of pressure change are opening condition (42.4%) and the 48-h survival rates were not key parameters to understanding the fish mortal injuries when significantly different between the three conditions [39]. Sensor they pass through hydraulic turbines. Recent laboratory research by Fish data is in line with the findings of Collins and Ruggles [36], Brown et al. [8] and [35] identified that the ratio of acclimation who studied several Francis turbines and found that salmonids had depth to nadir pressure is the most predictive variable for the the maximum survival rate when turbines were operated near peak probability of mortal injury of juvenile Chinook salmon for Kaplan efficiency. For the live fish studies at Cougar Dam, it is possible that turbines and the likelihood of mortal injury increased with higher the smaller sample size (40) used in the peak efficiency condition ratios. The lower nadir pressure ranges that were observed at the was not large enough to show the survival difference than at the three Francis turbine sites suggested that surface acclimated fish other two test conditions. could have higher mortality when passing them than passing the Fish size and collisions may have big impact on the higher live AHT Kaplan turbine at Wanapum Dam. These results also have fish mortality at Arrowrock Dam among the three Francis turbines. great implications for both turbine operation and fish-friendly Early studies found that fish size was a major factor to fish mortality turbine design: operating the turbine unit in higher nadir pres- in the Francis turbine units and fish with the larger size are linked sure condition for existing turbines and designing new turbines to to more mechanical injuries or mortalities [37]. Turnpenny [10] also have higher nadir pressure can help lower the probability of mortal found that fish mass and fish orientation relative to the blade had injury due to barotrauma. For example, for juvenile salmons, which important influences on the probability of collisions. Small fish have median acclamation depth of 6.7 m [42], operating the turbine (<20 g) can be swept around the blade by the water even when at the peak efficiency condition (median nadir pressure 56 kPa) their center of gravity fell within the direct path of the blade. Large rather than the maximum operation condition (median nadir fish, on the other hand, tend to follow their original trajectories due pressure 24 kPa) at Cougar Dam can reduce the probability of fish to their inertia, which increases their probability of collision. The mortal injury by the factor of 4.2 [35]. For new designed Francis live fish tested at Arrowrock Dam were almost twice in size as those turbines, if the nadir pressure could be increased from 50 kPa (the at Cougar Dam and Detroit Dam, which could lead to higher approximately median nadir pressure observed at three study sites) probability of collisions with the turbine runner blades and other to atmospheric pressure 101.4 kPa, the probability of mortal injury fixed structures. The higher probability of collision could directly due to barotrauma could be reduced by the factor or 11.1. contribute to the higher live fish mortality rate at Arrowrock Dam.

3.5. Comparison of Sensor Fish results with live ﬁsh results 3.6. Sources of error

The correlation between the Sensor Fish data and live fish 48-h Sensor Fish data enabled in-situ evaluations of hydraulic con- survival rate [38e40] at the three Francis turbines is non- ditions that fish experienced during the passage through Francis conclusive (Table 5). Among the three turbines, live fish had the turbines at three study sites. Each Sensor Fish measurement

Table 5 Comparison of Sensor Fish that experienced severe events (collision and shear) and live ﬁsh survival rates in each study. Live Fish data are from Normandeau et al. [38e40].At Cougar Dam, the same pool of ﬁsh was used for all three operation conditions.

Arrowrock Dam Detroit Dam Cougar Dam

Min opening Max opening Peak efﬁciency

Valid Sensor Fish releases 5 19 4 3 4 Sensor Fish with severe collisions (%) 100 84 75 100 50 Sensor Fish with severe shear events (%) 40 100 100 100 100 Fish Species Rainbow trout Rainbow trout Juvenile spring chinook salmon Number of Released Fish 27 170 169 170 40 Fish length (mm) 200e400 112e246 124e230 48-h Survival (±SE) (%) 11.1 (6.1) 54.1 (3.8) 36.4 (4.0) 42.4 (4.1) 37.1 (8.1) T. Fu et al. / Renewable Energy 99 (2016) 1244e1252 1251 represented a unique passage path that fish would take during the [2] G.F. Cada, The development of advanced hydroelectric turbines to improve fi e turbine passage. However, the number of valid datasets from each sh passage survival, Fisheries 26 (2001), 14 13. [3] F.K. Cramer, R.C. Oligher, Passing fish through hydraulic turbines, Trans. Am. study was limited, which prevented researchers from doing more Fish. Soc. 93 (1964) 243e259. statistical analysis and inferences. The limited sample size was due [4] V.I. Tsvetkov, D.S. Pavlov, V.K. Nezdoliy, Changes in hydrostatic pressure lethal fi e to two factors: 1) not enough Sensor Fish were released; and 2) to the young of some freshwater sh, J. Ichthyol. 12 (1972) 307 318. [5] D.L. Beyer, B.G. D'Aoust, L.S. Smith, Decompression-induced bubble formation some Sensor Fish were damaged or not recovered. However, this in salmonids: comparison to gas bubble disease, Undersea Biomed. Res. 3 (4) study can help plan future Sensor Fish studies on sample size re- (1976) 321e338. quirements. For example, if studies would be done when turbine [6] J.L. Rummer, W.A. Bennett, Physiological effects of swim bladder over- fi expansion and catastrophic decompression on red snapper, Trans. Am. Fish. units were operated off the peak ef ciency conditions, more sam- Soc. 134 (2005) 1457e1470. ples might be needed taking into the consideration of possibilities [7] R.S. Brown, T.J. Carlson, A.E. Welch, J.R. Stephenson, C.S. Abernethy, of Sensor Fish damage and not being recovered. B.D. Ebberts, et al., Assessment of barotrauma from rapid decompression of depth-acclimated juvenile Chinook salmon bearing radiotelemetry trans- mitters, Trans. Am. Fish. Soc. 138 (2009) 1285e1301. 4. Conclusions [8] R.S. Brown, B.D. Pflugrath, A.H. Colotelo, C.J. Brauner, T.J. Carlson, Z.D. Deng, A.G. Seaburg, Pathways of barotrauma in juvenile salmonids exposed to simulated hydroturbine passage: Boyle's law vs. Henry's law, Fish. Res. 121 Sensor Fish were used to evaluate in-situ hydraulic conditions (2012) 43e50. that fish experienced when passing through three Francis turbines. [9] M.G. Feathers, A.E. Knable, Effects of depressurization upon largemouty bass, e In all three studies, Sensor Fish experienced more severe collisions North Am. J. Fish. Manag. 3 (1983) 86 90. [10] A.W.H. Turnpenny, M.H. Davis, J.M. Fleming, J.K. Davies. Experimental Studies than severe shear events in the stay vane/wicket gate region, which Relating to the Passage of Fish and Shrimps through Tidal Power Turbines. is consistent to the observation of the AHT Kaplan turbine at Marine and Freshwater Biology Unit, National Power, Fawley, Southhampton, Wanapum Dam. The comparison with the AHT was intended as a Hampshire, England. [11] J. Hogan, The effects of high vacuum on fish, Trans. Am. Fish. Soc. 70 (1941) reference instead of a direct comparison between Francis and 469e474. Kaplan turbines because the flow and power generation of the AHT [12] J.F. Muir, Passage of young fish through turbines, J. Power Div. Proc. Am. Soc. are not comparable to those of the three Francis turbines. In the Civ. Eng. 85 (1959) 23e46. [13] J.M. Becker, C.S. Abernethy, D.D. Dauble, Identifying the effects on fish of turbine runner region, all Sensor Fish at Detroit Dam and Cougar changes in water pressure during turbine passage, Hydro Rev. 22 (5) (2003) Dam experienced severe shear events while only 1% of the Sensor 32e42. Fish experienced severe shear events in the AHT Kaplan turbine, [14] J.R. Stephenson, A.J. Gingerich, R.S. Brown, B.D. Pflugrath, Z. Deng, T.J. Carlson, fl et al., Assessing decompression in fishes using a mobile aquatic barotrauma suggesting that the ow condition in the runner region could be laboratory: case study examining the incidence of barotrauma in neutrally more turbulent in the Francis turbines than in the AHT Kaplan and negatively buoyant juvenile salmonids exposed to simulated hydroturbine. Among the three turbine operating conditions at Cougar turbine passage, Fish. Res. 106 (2010) 271e278. e Dam, fewer Sensor Fish experienced severe collisions under the [15] P. Kumar, R.P. Saini, Study of cavitation in hydro turbines a review, Renew. Sustain. Energy Rev. 14 (2010) 374e383. peak efficiency condition than under the minimum and maximum [16] D.A. Neitzel, D.D. Double, Survival estimates for juvenile fish subjected to a opening conditions. The median nadir pressure and the nadir laboratory-generated shear environment, Trans. Am. Fish. Soc. 133 (2004) e pressure range were also higher under the peak efficiency condi- 447 454. [17] Z. Deng, G.R. Guensch, C.A. McKinstry, R.P. Mueller, D.D. Dauble, tion than the other two wicket gate opening conditions. These M.C. Richmond, Evaluation of fish-injury mechanisms during exposure to differences suggested that a better hydraulic conditions can be turbulent shear flow, Can. J. Fish. Sci. Aquat. 62 (2005) 1513e1522. achieved when operating the Francis turbine at the optimized [18] G. Cada, J. Loar, L. Garrison, R. Fisher Jr., D. Neitzel, Efforts to reduce mortality to hydroelectric turbine-passed fish: locating and quantifying damaging shear wicket gate opening, which can guide the operation to provide the stresses, Environ. Manag. 37 (2006) 898e906. most possible fish friendly passages for existing turbines. For newly [19] K. Von Raben, Regarding the problem of mutilations of fishes by hydraulic designed turbines, variable speed turbine could be considered to turbines, Die Wasserwirtsch. 4 (1957) 97e100. fi [20] E. Monten, Fish and Turbine: Fish Injuries during Passage through Power achieve sh friendly passage when technologies are available. In Station Turbines, Vattenfall, Stockholm, Sweden, 1985. addition, Sensor Fish experienced lower median nadir pressure, [21] D.J. Solomon, Fish Passage through Tidal Energy Barrages, Technical report for higher magnitude and rate of pressure change when passing the energy technology support unit: Harwell, UK, 1988. ETSU TID4056. [22] Z. Deng, T.J. Carlson, G.R. Ploskey, M.C. Richmond, D.D. Dauble, Evaluation of three Francis turbines than the AHT Kaplan turbine at Wanapum blade-strike models for estimating the biological performance of Kaplan Dam. Although whether these higher rates of the pressure change turbines, Ecol. Model. 208 (2007) 165e176. would cause higher barotrauma rates has not been evaluated in a [23] J.W. Ferguson, G.R. Ploskey, K. Leonardsson, R.W. Zabel, H. Lundqvist, controlled laboratory setting, studies have clearly shown that the Combining turbine blade-strike and life cycle models to assess mitigation strategies for fish passing dams, Can. J. Fish. Aquat. Sci. 65 (2008) 1568e1585. probability of fish mortal injury could be reduced by increasing [24] K. Subramanya, Hydraulic Machies, Tata McGraw Hill Education Private nadir pressure, which can be used to help design new turbine units. Limited, 2013. [25] EPRI, Fish Entrainment and Turbine Mortality Review and Guidelines, EPRI, 1992. TR-101231. Acknowledgement [26] G.F. Franke, D.R. Webb, R.K. Fisher, D. Mathur, P.N. Hopping, P.A. March, et al., Development of Environmentally Advanced Hydroturbine System Concepts, fi Report prepared for the Department of Energy under Contract DE- The eld data collection and initial data analysis at Cougar Dam AC07e96ID13382, 1997. and Detroit Dam was funded by the U.S. Army Corps of Engineers, [27] Eicher Associates, Turbine-related Fish Mortality: Review and Evaluation of Portland District. The field data collection and initial data analysis Studies, Electric Power Research Institute, Palo Alto, California, 1987. EPRI AP- 5480. at Arrowrock was funded by the Boise Project Board of Control. The [28] I. Serrano, P. Rivinoja, L. Karlsson, S. Larsson, Riverine an dearly marine sur- detailed analysis and writing of this article was funded by the U.S. vival of stocked salmon smolts, Salmo salar L., descending the Testebo River, Department of Energy Wind and Water Power Technologies Office. Sweden, Fish. Manag. Ecol. 16 (2009) 386e394. e fi [29] O. Calles, L. Greenberg, Connectivity is a two-way street the need for a The study was conducted at Paci c Northwest National Laboratory, holistic approach to fish passage problems in regulated rivers, River Res. Appl. operated by Battelle for the U.S. Department of Energy. 25 (2009) 1268e1286. [30] Z. Deng, T.J. Carlson, J.P. Duncan, M.C. Richmon, Six-degree-of-freedom Sensor Fish design and instrumentation, Sensors 7 (2007) 3399e3415. References [31] Z. Deng, J. Lu, M.J. Myjak, J.J. Martinez, C. Tian, S.J. Morris, et al., Design and implementation of a new autonomous Sensor Fish to support advanced hy- [1] S.I. Yannopoulos, G. Lyberatos, N. Theodossious, W. Li, M. Valipour, dropower development, Rev. Sci. Instrum. 85 (2014) 115001. A. Tamburrino, et al., Evolution of water lifting devices (pumps) over the [32] Z. Deng, T.J. Carlson, J.P. Duncan, M.C. Richmond, D.D. Dauble, Use of an centuries worldwide, Water 7 (9) (2015) 5031e5060. autonomous sensor to evaluate the biological performance of the advanced 1252 T. Fu et al. / Renewable Energy 99 (2016) 1244e1252

turbine at Wanapum Dam, J. Renew. Sustain. energy 2 (2010) 053104. Project, Boise, Idaho, Report prepared for Boise Project Board of Control, Boise, [33] F. Avellan, Introduction to cavitation in hydraulic machinery, in: The 6th In- Idaho, Normandeau Associates, Inc., Drumore, Pennsylvania, 2011. ternational Conference on Hydraulic Machinery and Hydrodynamics, 2004. [39] Normandeau Associates, Inc, Estimates of Direct Survival and Injury of Juve- Timisoara, Romania, October 11e22. nile Chinook Salmon (Oncorhynchus tshawytscha) Passing a Regulating Outlet [34] X. Escaler, E. Egusquiza, M. Farhat, F. Avellan, M. Coussirat, Detection of and Turbine at Cougar Dam, Oregon, Report prepared for the U.S. Army Corps cavitation in hydraulic turbines, Mech. Syst. Signal Process. 20 (2006) of Engineers, Portland District-Willamette Valley Project, Portland, Oregon, 983e1007. Normandeau Associates, Inc., Drumore, Pennsylvania, 2010. [35] R.S. Brown, A.H.A. Colotelo, B.D. Pflugrath, C.A. Boys, L.J. Baumgartner, Z. Deng, [40] Normandeau Associates, Inc, Estimates of Direct Survival and Injury of Juve- et al., Understanding barotrauma in fish passing hydro structures: a global nile Rainbow Trout (Oncorhynchus mykiss) Passing Spillway, Turbine, and strategy for sustainable development of water resources, Fisheries 39 (2014) Regulating Outlet at Detroit Dam, Oregon, Report prepared for the U.S. Army 108e122. Corps of Engineers, Portland District e Willamette Valley Project, Portland, [36] C.P. Ruggles, N.H. Collins, Fish Mortality as a Function of the Hydraulic Oregon, Normandeau Associates, Inc., Drumore, Pennsylvania, 2011. Properties of Turbines, Canadian Electrical Association, Montreal, 1981. [41] Y. Pannatier, B. Kawkabani, C. Nicolet, J. Simond, A. Schwery, P. Allenbach, Report G 144. Investigation of control strategies for variable-speed pump-turbine units by [37] M.C. Bell, A.C. Delacy, G.J. Paulic, A Compendium on the Success of Passage of using a simplified model of the converters, IEEE Trans. Ind. Electron. 57 (2010) Small Fish through Turbines, 1967 (Report submitted to the U.S. Army Corps 3039e3049. of Engineers, Noth Pacific Division, Portland, OR). [42] B.D. Pflugrath, R.S. Brown, Maximum neutral buoyancy depth of juvenile [38] Normandeau Associates, Inc, Assessment of Direct Survival/injury of Fish Chinook salmon: implications for survival during hydroturbine passage, Passing through the Arrowrock Dam and Arrowrock Dam Hydroelectric Trans. Am. Fish. Soc. 141 (2012) 520e525.