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Figures 3 and 4 are the predicted PV power of the compressor and the expander respectively. Due to a redistribution of fluid mass in the cooler, the PV loops travel quite a few cycles before they converge. The PV power of the compressor (integration of the PV loop) plus the I^{2}R and hysteresis losses gives the total motor power of the compressor. The Expander PV power (integration of the PV loop) minus expander losses as mentioned above gives the net cooling of the cooler.
Figure 5 is a correlation between the predicted PV loop and that of the experimental data. The slight shift in the data could have been caused by the presence of extra volume introduced by the pressure sensor. Figure 5 Figures 6 and 7 are correlations between the third order analysis and the experimental data of a Lucas Stirling Cooler on cooling capacity and specific power respectively.
In Figure 8, the third order analysis is compared to the data of a Philips Stirling Cooler. The optimum frequency predicted by the model compares favorably with the experimentally determined optimum frequency of the cooler. In Figure 9, the impact of dead volume on the optimum frequency of operation is shown.
Figure 10 is a nodal network diagram of a Pulse Tube. The same modeling approach for Stirling can also be applied to Pulse Tubes. Figure 10 To show the accuracy of this third order model, a blind test was conducted with the help of Dr. Ray Radebaugh of NIST. The model was used to predict the performance of a pulse tube built by Dr. Radebaugh, who had not yet published the test data of this pulse tube. Figures 11 and 12 compares the prediction with the experimental data of cooling capacity and specific power of the pulse tube. As one can see, the third order approach is a very powerful tool in the analysis of cryocoolers, if done correctly.
"Experimental and Predicted Performance of the BEI MiniLinear Cooler", Proc. of the 9th International Cryocooler Conference, Waterville, New Hampshire, P119, 1996 (with D.T.Kuo and A.S.Loc). "Prediction of Natural Frequency of the NASA 80K Cooler by the Stirling Refrigerator Performance Model", Cryogenics, 1994, vol. 34, No. 5, p.383 (with L.G. Naes and T.C. Nast). "Validation of the Stirling Refrigerator Performance Model Against the Oxford Refrigerator", Advances in Cryogenic Engineering, 1994, vol. 39, p.1359 (with I.E. Spradley and W.G. Foster). "Validation of the Stirling Refrigerator Performance Model Against the Philips/NASA Magnetic Bearing Refrigerator", Proc. of the 7th International Crycooler Conference, 1993, vol. p.280 (with I.E. Spradley). "Computer Simulation Model for Lucas Stirling Refrigerators", Cryogenics, 1992, vol. 32, No. 2, p. 143. (With I.E. Spradley, P.M. Yang and T.C. Nast.) "A Third Order Computer Model for Stirling Refrigerators", Proc. Advances in Cryogenic Engineering, 1992, vol. 37B, p. 1055. (With I.E. Spradley.) Abstract Download The same technique was applied to Pulse Tube coolers with great success also. "A Blind Test on the Pulse Tube Refrigerator Model", in Proc. of Advances in the Cryogenic Engineering, 1996, Vol. 41, p.13831388.(with Ray Radebaugh). Abstract Download "Validation of the Pulse Tube Refrigerator Model Against a Lockheed Built Pulse Tube Refrigerator", Cryogenics, 1996, Vol. 36, No.10, p.871. Abstract Download Do You Know Someone Who Needs A Job in Engineering, Physics or Chemistry? About the author Dr. Sidney Yuan is a consultant in the field of Low Temperature Physics and Cryogenics, and has written a Book on Cryogenics and published extensively in the field. EMail. Bookmark This Page Send This Page To A Friend Place Your Ad Here For As Little As $1 Per Day About Us  Add URL  Advertise with Us  Auction  Awards  Contact Us  Discussion Forum  Links  Search This Site  Send This Page  Shop  Top Ten Sites Copyright 2000 Yutopian, All Rights Reserved 
