Research Into the Drive Transition of 1111111111111111111111111

THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS 345 E. 47th St., New York, N.Y. 10017 97-GT-171

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ZANG SHUSHENG MENG HONGTAO LI SHUYING SUN HAIOU

Dept of Power Eng. Harbin Engineering University, Harbin 150001, P. R. C.

ng = rotational speed of output shaft of gas turbine [rpm) T = time needed for changing diesel engine fuel control lever [s] ABSTRACT Ta = elan:magnet time constant of servomotor used for fuel A small test installation of Combined Diesel or Gas control [s] turbine(C0000) was made, its primary aimed at investigating the Tm = machine time constant of servomotor used for fuel control [a] changes of various operational parameters of the two engines in the Go = voltage of signal with set diesel speed [mV] change-over process. Firt the computer sinmation of this process is 6(s) = trattsfonnation function of speed governor cared out it the papa. Variations of torque turd rotational speed on gp = coefficient the transmission shafts wider different rates of fuel supply and the Kind = coefficient affect of hydraulic coupling on the change -over process are investigated. Then, the comparison i/3 made of variation of speed and 86 = real angle of engine fuel control lever [degree] torque by?! governing with that by PID governing. The rack shows 04 = ogle of tel control lever [degree] that the rate of increase or decrease of diesel engine Awl supply has singnificant effect on the variation of torque, and the change of = caltnroPI governor Sin* angle [degree] parametas in governing system has markable effect on the speed and torque in change-over process, especially on the peake value of diesel engine torque. INTRODUCTION At present CODOG plants have become a main type of NOMENCLATURE propulsion plant for major surface warship' s. The altinnative Md = torque of diesel engine (Mn) operation of diesel engine and gas turbine leads them to bring their My = torque of input shaft of hydraulic coupling (Mn] tam into full play, thus the Vasa= of propulsion plant is Jd ornament of inertia of shafting of diesel engine [kg.m.e 2] kept efficient The change-over between two engines is a special process of CODOG pin In this process, in order to reduce the = total moment of inertia of output shaft of hydraulic coupling mechanical impact between gears and within the coupling, it is and input shaft of SSS check [kg,m22 1 required to make the speed difference in power trammtinion between the two engines as minimum as possible. Therefore, how to control Jg a total mane= of inertia of output shaft of gas turbine and the principal parameter% such as the fuel supply, the rate of inmate input shaft of $SS clutch [kg.m.s2] or decrease of engine fuel supply, and the corresponding change of a a total moment of output shaft of SSS clutch and shaft of engine load, is essential for meeting the above-mentioned requitement_ Consequently, the study of this problem becomes hydraulic dynamometer [k&nial] indispensable to the application of CODOG plant ad a rotational speed of diesel engine [rpm] Based on a small test imitation of CODOG plant, which is to be rotational speed of input shaft of hydraulic coupling [rpm] used for experiment, we calculated variations of torque and MIUMaran BY nf rotational speed of shalt of hydraulic dynamometer [rpm] speed on the output shafts and hydraulic coupling shafts of the two

Presented at the International Gas Turbine & Aeroengine Congress & Exhibition Orlando, Florida — June 2-June 5,1997 engines. The calculation shows that the rate of increase or decrease of engine fuel supply in the change -over process deserves extra attention in the design and use of a CODOG plant_ Mt -Mr =(Js -Jf ) titdi ) 3x4 ( TEST INSTALLATION nt = nf The diagram of test installation of the CODOG plant is shown in Fig. 1. It consists of a single-shaft constant-speed gas turbine, a diesel engine, hydraulic coupling two Synchronons-Self-Shifting (SSS) In case the load is taken by diesel engine only, the SSS cluth on rletrbps, gas rmbine side is disengaged, the output shaft of gas turbine is a gearbox ad a hydraulic dynamometer. The principal/ Downloaded from http://asmedigitalcollection.asme.org/GT/proceedings-pdf/GT1997/78682/V001T02A003/2408503/v001t02a003-97-gt-171.pdf by guest on 02 October 2021 parameters of the two engines are as follows: cormected with the input end of SSS clutch only. Gas turbine: rated pow Z34 kw In addition to Eq.(1), there are other equations as below. rated rpm 1500 For gas turbine shaft and input shaft of SSS clutch no-load rpm 1560 Diesel engine: rated power 35 kw M = J dnz (5) MS rpm 2000 g gdt For output shaft of hydraulic coupling and hydraulic dynamometer shaft I gas turbine I—I S.S.S gear box mdYn eteer el dialf H dt (8) diesel rrcoi ing E fly = of In case the diesel engine, gas turbine and dynamometer work in common, the output shaft of hydraulic coupling, gaa turbine shaft and Fig.] Diagram of CODOG test Installation dynamometer shaft maintain the same speed. In addition to Eq.(1), there are other equations as blow

EQUATION OF CHANGE -OVER PROCESS M +M -M =(J +J +J ) dnY The mathematical desaeption of the change-over process of a y syr dt (7) CODOG plant thin mode is mainly given by equations of motion of n = n =111 engine rotors, chat equations of speed governing hydrolic 7 coupling and load- In addition, the composition of equations may Besichs, the ton carves betw-een the Epee& torque and angle vary slightly in light of the regime of change-over process. of fuel control lever 8d, that expresses the governing characteristic of In case the load is taken by the gas turbine only, the SSS clutch dismal engine, are given in this paper by way of experimental on the diesel engine side is disengaged, the output shaft of the measurement It is expressed in the form below hydraulic coupling works together with one end of the SSS clutch ht, = (8) only. The equations are as follows. Kaaet, The motion equation of diesel engine and input shaft of the in which, Odd is the real angle of engine fuel control lever, mid lrychudic coupling Eldf 3d-Om In fact, the change rate of this parameter reflects the rate of fuel °Piny, On is the centrifugal governor adjusting angle. There M 4 -M y = Ja d&ind (1) is where, Md is an output torque of diesel engine, M y is tm input torque 8, = Kat% of the hydraulic coupling. Jd is the moment of inertia of both the So that, according to Eq.(1) shafts of diesel engine and the input end of hydraulic coupling. This equation will not vary in both cases below. The Jy is the moment of inertia of both output shaft of hydyalic ea --My = Old +1.4 —dad ) ( 9 ) coupling and input shaft of the SSS clutch, and the motion equation 1C4,4 dt of them is 1 2rad where 1.4 = du, M = J K K d 60 7 7 dt (2) M _ The gas turbine used in our ten installalion operates in constant The motion equation of gaa turbine and dynainomeier shaft is speed mode. Btu the speed vanes slightly raider different conditions of load. According to experimental data, we have the following relation between torque ad speed:

2 1750 1750 1700 1700 1850 1850 1603 ietx) 1 1550 1 1550 1500 15C0 Downloaded from http://asmedigitalcollection.asme.org/GT/proceedings-pdf/GT1997/78682/V001T02A003/2408503/v001t02a003-97-gt-171.pdf by guest on 02 October 2021 case! 1450 +-03upliig 1450 geStufbil 1400 444ynemometer 1400 1350 135° 0 50 100 150 200 250 300 350 400 0 50 100 150 200 250 300 350 400 ane(s) 11mM 203 odesd 150 -scOlitUng 150

-rgesturbin -*dynamometer kat 100

S 50

-50

-100 -100 50 100 150 ED 250 TO 360 400 0 SO 100 150 200 250 300 350 400 time tane(s)

Ftgl Variation of speed and torque with T-10 seconds F1g.3 Vartadon of speed and torque with T-60 seconds

i K y (n p -or) ago > nr (10) thar M I = 10 n s nr Ky K 7 (12) where, ago is the gas Outline speed with no load and a y is thin with 1 22 T = K— (J. +Jy +Jr ) load. y 60 • The torque toomitted by hydraulic coupling is a inaction of The load of this test instant/on is provided by a hydraulic difference between the pump wheel speed rrp and the mrbine wheel dynamometer. Under the condition of constant water eow the power p equals the diesel speed oy in the hydraulic couplin& in fad, o c:hanges in company with chasing speed, while the torque keeps engine output shaft speed od, so that unchanged. Thus the torque of dynamometer can be considered capsizal in the change-over process of this chive mode. M y =Ky .(od -ny ) (11) from Eq.(7) these are CALCULATION AND RESULT ANALYSIS The foregoing equations form the mathematical model of dynamic charatenstiar of change-over process of CODOG plant. On this baths calculation was made by use of difference equations. For the

1800 1750 1750 1703 1700 1653 1650 1600 1803 1550 1550 11500 1500 it 1453 Downloaded from http://asmedigitalcollection.asme.org/GT/proceedings-pdf/GT1997/78682/V001T02A003/2408503/v001t02a003-97-gt-171.pdf by guest on 02 October 2021 1450 1400 camel 1350 1400 1300 dynamometer 1350 7- 1250 1300 20 40 60 80 100 123 0 20 40 80 80 100 123 Irne(s) trne(s) 1503

203 500 100 3. g g -103 a -500 <>68188 2 -KO Ci 3e -•0:0143Rn9 -30 I204 0 -1000 - -1-98032881 : - - 8e8s A8 1 1 edynamoneter 4° ° r -wdynomerntere -1500 -500 • 0 23 40 60 80 103 120 0 20 40 60 80 100 120 One(s) this(s) Flg.S varthtion of speed and torque with PI govendng Fig.6 Kir1.0 variation of speed and torque with PI governing

1750 1700 1853 16C0 1553 1500 1450 1400 1393 1300 23 40 60 53 100 123 0 20 40 60 8D 1C0 123 firre(8) iime(s) Fig.? Variation of speed and torque with PID governing

calculation the following regimes were selected as blast regime of GOVERNING SYSTEM DESIGN change-ova process: In this paper, we study the governing system of OODOG test In the case of change-over from gas turbine drive to diesel engine inetallation and inspect the effect of variation of governing drive parameters on this process. Diesel engine: power no-load Figure 4(a) is a stmaure of the governing system designed Zip 1400 according to Eqs.(9) and (12). Because of the value of Ta and Tm is Gas turbine: power 10 kw of ma level, far smaller than Td and Ty (100ms), and without imp 1554 considering load disturbance, Fig4(a) can be simplified to Fig4(b).

In otse of change-over from diesel engine chive to gas turbine Figures 5 and 6 show variation of speed and torque in ass of the Downloaded from http://asmedigitalcollection.asme.org/GT/proceedings-pdf/GT1997/78682/V001T02A003/2408503/v001t02a003-97-gt-171.pdf by guest on 02 October 2021 drive gain is Kr4.0 and 14=1.0 respectively, in which the governor is a PI Diesel engine: power 11A kw regulator. The range of 0-60 seconds shows the change-over process imp 1700 from gas turbine drive to diesel engine drive, and the range of 60-120 Gas turbine: power no-load seconds shows the process comnry to the above-mentioned process. mg 1560 Nat we see that the response of diesel speed in both processes is Both of the change-ova processes were carried out under different, and Kp has greater effect on the parameters of change-over constant speed naming of gas turbine, relying on the inaease or process. With Kr1.0, though response time of diesel engine speed is decrease of diesel engine fuel supply. a slightly longer than with Kp=4.0, the MOMS significanfly deaeases, In addition, the calculation was made in connection with the especially the peak value of torque of diesel engine decreases even foregoing mode of change-over. With the same changing range of greatly ( from -1430 to -440 N.m and from 1300 to 340 Km). diesel engine feel control lever. 10 seconds and 60 seconds were Figure 7 shows the variation of speed and torque with PID selected as the time needed for changing the position of fuel control regulator. As compared with PI regulator, the change of parameters in lever. This corresponds to the adoption of two diffaent rates of change-over process is slightly improved. increate or decrease of fuel supply to make power change-over of the two engines. Figure 2 shows the venation of speed and torque on the diesel engine shaft, hydraulic coupling output shaft, gas turbine shaft and dynamometer shaft with a time of 10 seconds for changing the diesel engine fuel control ltBa position. Similarly. Fig) corresponds to a case of 60 seconds. In addition. in these figures the range of 0-200 seconds, the change-over process from gas turbine drive to diesel engine drive, end the range of 200-400 seconds shows the change-over process from diesel engine drive to gas turbine chive. It can be seen from Fig.2 that there is brge difference of speed between the diesel engine shaft and the hydraulic coupling output shaft btu being in the mode of diesel engine drive. Even more evident variation of diesel engine torque can be seen from Fig). AS compared with engaging process, the variation of torque in (a) disengaging process is getter. and negative torque may roar. At the same tinze, the peak value of torque variation is by fer, fester than the torque in steady operation. For example, in the case of.T=10 seconds, the peak value of torque in the disengaging process is 150 Rm. while the steady value of torque in loaded °pennon is 65 Na In the same a the peak value of torque of hydraulic coupling output shaft is 72 Na which is, by br. smaBer than that of diesel engine shaft. This indicates that the adoption of hydraulic coupling has evident effect of torsional impact redaction on the dynamometer shaft. As for the diesel engine, its peak value of torque does not decrease. It am be seen from Fig.2 that the time, T, for done% the position of diesel engine fuel control lever, which corresponds to the rate of bet supply, has significant effect on torque. In the case of T=I0 seconds, comparing diesel engine in engaged mode with that in disengaged mode, the peek value of torque in both cases is 150 N.m (b) or -90 Na As for the torque of hydraulic coupling output shaft and dynamometer shaft, T has lean effect on then Ptg.4 Structure of the governing system

5 CONCLUSION In the case of constant speed control mode of gas ttubine, the engaganem and clisengement of a diesel engine will amse considereble variation of positive or negative torque in the change- over process of drive mode, and the peak value of torque will be by fur, greater than the value of torque in steady operation regime. The adoption of hydraulic coupling am bring in the reduction of torsional Downloaded from http://asmedigitalcollection.asme.org/GT/proceedings-pdf/GT1997/78682/V001T02A003/2408503/v001t02a003-97-gt-171.pdf by guest on 02 October 2021 impaa of the dynamometer hi the change-over process. The rate of increase or decease of diesel engine fuel supply has singnificant effect on the variation of torque, thus appropriate rate of increase or decrease of diesel fuel supply is considered to be a very impatient faaor. The change of parameters in governing system has markable effect to the speed and torque of change-over process, especially to the peak value of diesel engine torque. This point deserves extm attention in design of gaveling system Above-mentioned work is only a part of the reasech on the change-over process of drive mode in a CODOG plant, and the experimental work is going on.

REFERENCES 1. Dupuy, P. A., 1984, • Combined Diesel mid LM2500 Gas Turbine Propulsion Enhances Corvette! Frigate Missions", ASME Journal of Engnieezing for Gas Turbine and Power, Vol 106, pp 645- 653 2. Ha Ziqing, 1993, " Computerized model pacametem adaptive control system hydraulic power shift transmission durability test board*, Chinese Journal of Mechanical Engineering. vol. 29, No. 3, pp 79-85 3. Naaki Trmmni, laso Kiahimoto, Takayoahi Maeda, Imo Sato,1989, "Optimization of Control Parameter for Electronic Digital Governor, Journal of the M. E S. 3, VoL 24, pp 165-176 4. Shigeyoki Morita, Ifidekaza Filbert 1991, • SinmIttimi for Consolidated Control of the Engine and Controllable Pitch Propeller", Journal of the M. ES. j„ VoL 26, pp 606-613 5. Smith, D. A.. 1990, 'Comparative Controller Design for a Marine Gas Turbine Propulsion System", ASME Journal of Engineering for Gas Turbines and Power, Vol, 112, pp 182-186