Mass flow rate measurements for

CO2 cooling systems: methods and results

J. Daguin, M. Ostrega, T. Pakulski, P. Petagna, H. Postema, N. Spadavecchia, P. Tropea, B. Verlaat, L. Zwalinski, Forum on Tracking Detector Mechanics 2015 15-17 June, Amsterdam

Jérôme Daguin - PH/DT/DI 1 15 June 2015 Outline

1) Why do we want to measure mass flows? 2) Methods for mass flow measurement

3) Methods compatible with liquid CO2 requirements * Thermal mass flow measurements * Differential pressure mass flow measurements * Coriolis mass flow measurements 4) Methods compatible with two-phase fluids * Litterature for two-phase flow measurements * Coriolis two-phase mass flow measurements

Jérôme Daguin - PH/DT/DI 2 15 June 2015 Why do we want to measure mass- flow rate ?

* Liquid flows: * Flow regulation * Balancing of circuits * Two-phase flows: * Vapor quality evaluation

2-Phase Shielding wall Accumulator P7

Heat in Long distance (50-200m) P4-5 HFC Chiller Evaporator inside Manifold 5 detector (4-5)

6 Condenser 2

1 Pump Transfer line 3 Capillaries (3-4) (Heat exchanger) for flow 4 Jérôme Daguin - PH/DT/DI 3 distribuon 15 June 2015 Mass flow measurement methods

* Indirectly: * Typically mass flow is calculated based on the measurement of another data: flow speed, volumetric flow rate, pressure difference, etc. * Most common instruments: * Coriolis flow meters * Ultrasonic flow meters * Turbine flow meters * Differential pressure flow meters * Thermal flow meters

Jérôme Daguin - PH/DT/DI 4 15 June 2015 Mass flowrate for CO2

CO2 requirements: * High service pressure (110 bar) * Low temperature (-40°C) * Big range of temperature (-40°C to + 20°C) * Optional: Magnetic field resistant (to be used in experimental areas) * Optional: two-phase mass flow (to evaluate heat load through vapour quality) Instruments tested

Liquid Two-phase 1. Thermal flow meter 1. Coriolis flow meter 2. DP flow meter 3. Coriolis flow meter

Jérôme Daguin - PH/DT/DI 5 15 June 2015 Thermal mass-flow meter measurements

* 2 measuring principles: * Constant temperature differential: * Mass flow rate calculated as a function of the power needed to maintain a constant ∆T between the two sensors * Constant current: * Mass flow rate calculated as a function of the ∆T between the two sensors for a constant power Temperature sensors Heang element

Fluid

Jérôme Daguin - PH/DT/DI 6 15 June 2015 Thermal Mass-flow measurements @ TIF

* Thermal Instrument Company 601-9LT model with remote electronics * Compatible with magnetic field

* Calibrated for liquid CO2 * 0 to 15 g/s * -30 °C to +20 °C * 110 bar service pressure

Jérôme Daguin - PH/DT/DI 7 15 June 2015 Thermal Mass-flow measurements @ TIF

* Perfect correlation 20 bar with reference (coriolis) when subcooling is higher than 6°C/10 °C… * When subcooling is

“Low” subcooling lower, CO2 starts to evaporate on the heating sensor Subcooling before flowmeter Accumulator pressure Thermal mass flowmeter Coriolis mass flowmeter * Measurement lost

Jérôme Daguin - PH/DT/DI 8 15 June 2015

Differential pressure flowmeter

* Measurement principle: * Mass flow rate calculated based on the pressure difference created when fluid passes through a capillary

P1 P2

D Flow

L * Described by the Darcy-Weisbach equation

� = density � = dynamic viscosity

Jérôme Daguin - PH/DT/DI 9 15 June 2015 Differential pressure mass-flow measurements @ TIF

* Endress&Hauser Deltabar S PMD75 * DP measuring range: 0 to 3bar * Max working pressure: 160 bar * Max pressure difference: 160 bar * Temperature range: -40 to +85°C * Output: 4 to 20 mA * Compable with CMS magnec field levels on the balconies * Capillary * Standard off-the-shelf copper tube from CERN store * 1 m long * 2mm ID (not guaranteed)

Jérôme Daguin - PH/DT/DI 10 15 June 2015 Differential pressure mass-flow measurements @ TIF

Parameters of the test: * Coolant temperature: accumulator set point (-20°C,-10°C,0°C,+10°C) DP sensor * Flow rate: pump speed Capillary tube – variable (323 to 1400 rpm) 1 m long / 2 mm ID with stroke blocked at 5mm to adjust flow from 3 g/s to 20 g/s Flow

Jérôme Daguin - PH/DT/DI 11 15 June 2015 Differential pressure mass-flow measurements @ TIF

* Whole flow pumped through manifold loop 7324 * Scan flow rates from 3 to 20 g/s at different temperature setpoints * Temperature set point ~ 30 min settling time * Mass flow rate ~15 minute settling time * Log time stamps of steady conditions

Reference flow rate

Loop 7324

Jérôme Daguin - PH/DT/DI 12 15 June 2015 Differential pressure mass-flow measurements @ TIF – Analysis method

* Analytical calculation of the expected pressure drop for a given mass flow rate * For 1 to 20 g/s and -20 °C to + 15 °C * And for a 1 m long / 2 mm ID capillary:

* Simplified formula with 2% precision

Jérôme Daguin - PH/DT/DI 13 15 June 2015 Differential pressure mass-flow measurements @ TIF – Results

Capillary ID corrected by 0.1 mm => 10 % - 15% precision

Jérôme Daguin - PH/DT/DI 14 15 June 2015 Coriolis mass flow measurements

* Measuring Principle Coriolis Mass Flowmeters * Coriolis forces Fc are generated in oscillating systems when a liquid or a gas moves away from or towards an axis of oscillation * A Coriolis measuring system is of symmetrical design and consists of one or two measuring tubes, either straight or curved * A driver sets the measuring tube (AB) into a uniform fundamental oscillation mode * When the flow velocity v = 0 m/s, the Coriolis force Fc is also 0. At flowing conditions, i. e. flow velocity v > 0 m/s, the fluid particles in the product are accelerated between points AC and decelerated between points CB * The Coriolis force Fc is generated by the inertia of the fluid particles accelerated between points AC and of those decelerated between points CB * This force causes an extremely slight distortion of the measuring tube that is superimposed on the fundamental component and is directly proportional to the mass flowrate * This distortion is picked up by special sensors. Since the oscillatory characteristics of the measuring tube are dependent on temperature, the temperature is measured continuously and the measured values corrected accordingly

hp://krohne.com/en/products/flow-measurement/mass-flowmeters/measuring-principle/ Jérôme Daguin - PH/DT/DI 15 15 June 2015 Coriolis mass flow measurements – Liquid phase

* All current CO2 systems are using coriolis devices to measure liquid mass flows * Pros: * Several brands available (Krohne, Bronkhorst,…) * Flowmeters available for a wide range of systems (from few grams/s to more than 150 g/s) * Precise and reliable * OK for high pressure * OK for low temperatures (down to -40 °C) * Cons: * Cannot be used in magnetic fields * Expensive

Jérôme Daguin - PH/DT/DI 16 15 June 2015 Literature study for two-phase flow measurement

* A research was carried out to investigate about new ways to measure 2-phase flows * Researches in this field are focused mainly on air + water mixtures Ø Different than evaporating fluid… * 3 papers are of interest: ① Gas-liquid two-phase flow sampling measurement using a swirl sampler (2013) [1] ② A combination method for metering gas–liquid two-phase flows of low liquid loading applying Ultrasonic and Coriolis flowmeters (2014) [2] ③ Measurement of gas and liquid flow rates in two-phase pipe flows by the application of machine learning techniques to differential pressure signals (2014) [3]

Jérôme Daguin - PH/DT/DI 17 15 June 2015 Gas-liquid two-phase flow sampling measurement using a swirl sampler (2013)

* Extraction of a small fraction of the air- water mixture * Separation of the mixture into single gas and liquid * Flow rate of each phase is measured using conventional single-phase flowmeter (vortex and electromagnetic) * After measurement, the extracted flow returns to main stream again * Test conditions: * Gas superficial velocity= 10.0 – 24.0 m/s * Liquid superficial velocity= 0.02 – 0.18 m/s * Flow patterns= wavy flow, slug flow and annular flow Ø Total mass flow error is around 6%

Jérôme Daguin - PH/DT/DI 18 15 June 2015 A combination method for metering gas–liquid two- phase flows of low liquid loading applying Ultrasonic and Coriolis flowmeters (2014)

* Combination of an Ultrasonic and a Coriolis mass flowmeter (from Hendress-Hauser) to measure the mass flow rate of an air-water mixture * Ultrasonic flowmeter measures the flow rate of the gas phase only WG (for stratified flows with low liquid level) and the coriolis flowmeter the apparent mass flowrate WC * Models developed for the gas mass flow rate and gas quality * Two models coupled and Fixed-Point Iteration Method used to determine WG and x and finally WL * Test conditions: • Gas superficial velocity: 4 – 25.0 m/s • Liquid superficial velocity: 0.02 – 0.70 m/s • Flow patterns: stratified flow and annular flow. • Quality: 0.15 – 0.65 • Pressure: 0.2 – 0.5 Mpa * Error for the gas= 3.09% * Error for the liquid= 12.78%

Jérôme Daguin - PH/DT/DI 19 15 June 2015 Coriolis mass flow measurements – Two-phase fluid

* New device produced by Khrone for two-phase mass flow and density measurements * OPTIMASS 6400: * Twin bent tube technology * 3 independent measurements * Mass flow rate – Coriolis principle * Density – Natural frequency of an oscillating tube * Temperature * Can be operated with two-phase * Liquid range below 150 g/s * Gas range below 105 g/s * Accuracy measured at the factory with air/water mixture…

Jérôme Daguin - PH/DT/DI 20 15 June 2015 Optimass 6400 – Set-up @ TIF

* Optimass 6400 connected to TIF dummy load loop Transfer lines * Testing parameters: Manifold * Temperature from -20 °C to +5 °C Plant * Flow rate from 20 g/s to 105 g/s * Vapor quality from 0 to 70% (using heat load from 0 to 13 Accumulator Dummy load kW)

Jérôme Daguin - PH/DT/DI 21 15 June 2015 Optimass 6400 – Test protocol

* Whole flow pumped through manifold loop 7424 * Scan flow rates from 20 to 105 g/s at different temperature setpoints and different heat load * Temperature set point ~ 30 min settling time * Mass flow rate ~ 15 minute settling time * Heat load ~ 5 min settling time * Log time stamps of steady conditions

Reference flow rate

Loop 7424

Jérôme Daguin - PH/DT/DI 22 15 June 2015 Optimass 6400 – Data analysis

SCADA Logs: Sensor .csv export MATLAB pre- and Reference Raw .csv file for processing instruments signals each test day

MATLAB/REFPROP scripts for: MATLAB • Expected density User-observed steady state • Vapour quality steady-state timesteps time filter • Flow velocity Steady-state• Mass flow and data density errors

Jérôme Daguin - PH/DT/DI 23 15 June 2015 Optimass 6400 – Calculated Density

* How do we calculate density:

* Manifold inlet enthalpy h3 determined with REFPROP from manifold inlet pressure and temperature

* Sensor enthalpy h5 is the sum of h3 and the change in enthalpy due to the heat load Δh * Δh=P/ṁ * Sensor inlet density is determined with REFPROP from h5 and local pressure

Jérôme Daguin - PH/DT/DI 24 15 June 2015 Optimass 6400 – Results

* Optimass 6400: * Calculated Signals ① FT7524 mass flow ① Expected two-phase density ② DT7424 density ② Expected Vapour Quality ③ TT7424 temperature ③ Relative mass flow error ④ Relative density errors

* TIF plant references: * Data analysis ① FT3020 plant liquid flow rate REFPROP + MATLAB (①②③④) => ①② ② PT7024 Manifold supply * PLots ③ TT7024 Manifold supply MATLAB (①①) => ③ plotted vs ② ④ EHDL1, 2 Dummy Load Heaters MATLAB (②①) => ④ plotted vs ②

Jérôme Daguin - PH/DT/DI 25 15 June 2015 Optimass 6400 – Relative flow error vs Vapour quality

20% error up to 40 g/s

Jérôme Daguin - PH/DT/DI 26 15 June 2015 Optimass 6400 – Relative density error vs Vapour quality

20% error up to 40 g/s

Jérôme Daguin - PH/DT/DI 27 15 June 2015 Conclusions

* Mass flow measurements for CO2 not trivial… * Liquid phase measurements: * Coriolis mass flow meter very precise and reliable * Not compatible with magnetic field * DP mass flow meter tested at TIF gives fairly good results * Precision of 10 – 15%

* Thermal mass flow meter not working for CO2 close to saturation * Two-phase measurements: * Optimass 6400 usable for flow below 40 g/s * Precision around 20 % for the flow measurement * Precision around 20 % for the density measurement

Jérôme Daguin - PH/DT/DI 28 15 June 2015 Acknowledgement

* Thanks to: * Tym Pakulsky and Nicola Spadavecchia for the intensive testing sessions * Norbert Frank, Cédric Landraud and Jérome Noël for their precious hand * Bart Verlaat for the help with MATLAB scripts

Jérôme Daguin - PH/DT/DI 29 15 June 2015 Thank you for your attention !

Jérôme Daguin - PH/DT/DI 30 15 June 2015 References

* [1]: Liang, F., Wang, D., Chen, J., & Yang, G. (2013). Gas–liquid two-phase flow sampling measurement using a swirl sampler. Flow Measurement and Instrumentation, 33, 145-152. * [2]: Xing, L., Geng, Y., Hua, C., Zhu, H., Rieder, A., Drahm, W., & Bezdek, M. (2014). A combination method for metering gas– liquid two-phase flows of low liquid loading applying ultrasonic and Coriolis flowmeters. Flow Measurement and Instrumentation, 37, 135-143. * [3]: Shaban, H., & Tavoularis, S. (2014). Measurement of gas and liquid flow rates in two-phase pipe flows by the application of machine learning techniques to differential pressure signals. International Journal of Multiphase Flow, 67, 106-117.

Jérôme Daguin - PH/DT/DI 31 15 June 2015