The compression mechanism in a twin screw compressor consists of two helical rotors. In this work, a method is presented for computing the forces and moments induced on each rotor due to gas compression. These are defined as the compression loads. The helical rotor surfaces are defined by the end profiles, wrap angle and rotor length. The 3D surface of each rotor is mapped to 2D integration regions. These regions correspond to the surfaces associated with individual compression chambers. The compression loads are computed by integrating the chamber pressure over the rotor surfaces. The integrals are evaluated at incremental values of the rotor angular position. The method is presented and implemented for a specific compressor configuration. The compression loads are resolved to forces at the bearing locations. These bearing forces are presented for operating pressures which represent an under-pressure condition. A frequency analysis demonstrates the rich frequency content of the bearing forces due to the sharpness of the compression loads as a function of the rotor angular position. In addition, it is demonstrated that the moment load about the axis of rotation induced on the female is approximately 12 percent of that induced on the male. Therefore, the female rotor motion approaches that of an idler gear.

1.
Adams, G. P. and Soedel, W., 1992, “Remarks on Oscillating Bearing Loads in Twin Screw Compressors,” Proceedings of the 1992 International Compressor Engineering Conference at Purdue, West Lafayette, IN 47907, July, pp. 439–447.
2.
Adams, G. P., 1993, “Modelling and Computer Simulation of Rotor Chatter and Oscillating Bearing Forces in Twin Screw Compressors,” Ph.D. thesis, Purdue University, West Lafayette, IN 47907, December.
3.
Adams, G. P., and Soedel, W., 1994, “Dynamic Simulation of Rotor Contact Forces in Twin Screw Compressors,” Proceedings of the 1994 International Compressor Engineering Conference at Purdue, West Lafayette, IN 47907, July, pp. 73–78.
4.
Andrews, R. W., 1990, “Noise Source Identification in Twin-Screw Compressors,” Master’s thesis, Purdue University, West Lafayette, IN 47907, August.
5.
Brablik, J., 1982, “Analytical Model of an Oil-Free Screw Compressor,” Proceedings of the 1982 International Compressor Engineering Conference at Purdue, West Lafayette, IN, 47907, July, pp. 356–364.
6.
Firnhaber, M. A., and Szarkowicz, D. S., 1980, “Modeling and Simulation of Rotary Screw Compressors,” Proceedings of the 1980 International Compressor Engineering Conference at Purdue, West Lafayette, IN, 47907, July, pp. 305–310.
7.
Fujiwara, M., Mori, H., and Suwama, T., 1974, “Prediction of the Oil-Free Screw Compressor Performance using Digital Computer,” Proceedings of the 1974 International Compressor Engineering Conference at Purdue, West Lafayette, IN 47907, July, pp. 186–189.
8.
Fujiwara, M., Katsuhidi, K., Matsunaga, T., and Watanabe, M., 1984, “Computer Modeling for Performance Analysis of Rotary Screw Compressor,” Proceedings of the 1984 International Compressor Engineering Conference at Purdue, West Lafayette, IN, 47907, July, pp. 536–543.
9.
Koai, Kwang-lu, and Soedel, W., 1990a, “Gas Pulsations in Screw Compressors - Part I Determination of Port Flow and Interpretation of Periodic Volume Source,” Proceedings of the 1990 International Compressor Engineering Conference at Purdue, West Lafayette, IN, 47907, July, pp. 369–377.
10.
Koai, Kwang-lu, and Soedel, W., 1990b, “Gas Pulsations in Screw Compressors - Part II Dynamics of Discharge System and its Interaction with Port Flow,” Proceedings of the 1990 International Compressor Engineering Conference at Purdue, West Lafayette, IN, 47907, July, pp. 378–387.
11.
Koai, Kwang-lu, and Soedel, W., 1990c, “Contributions to the Understanding of Flow Pulsation Levels and Performance of a Twin Screw Compressor Equipped with a Slide Valve and a Stopper for Capacity Control,” Proceedings of the 1990 International Compressor Engineering Conference at Purdue, West Lafayette, IN, 47907, July, pp. 388–397.
12.
Margolis
D. L.
,
1978
, “
Analytical Modeling of Helical Screw Turbines for Performance Prediction
,”
ASME Journal of Engineering for Power
, July, Vol.
100
, No.
3
, pp.
482
487
.
13.
Sangfors, B., 1982, “Analytical Modeling of Helical Screw Machine for Analysis and Performance Prediction,” Proceedings of the 1982 International Compressor Engineering Conference at Purdue, West Lafayette, IN, 47907, July, pp. 135–139.
14.
Sangfors, B., 1984, “Computer Simulation of the Oil Injected Twin Screw Compressor,” Proceedings of the 1984 International Compressor Engineering Conference at Purdue, West Lafayette, IN, 47907, July, pp. 528–535.
15.
Sauls, J., 1988, “Slide Valve Design Using a Screw Compressor Performance Simulation Model,” SRM Compressor Conference.
16.
Shaw, D. N., 1988, “Screw Compressors Control of Vi and Capacity: The Conflict,” Proceedings of the 1988 International Compressor Engineering Conference at Purdue, West Lafayette, IN 47907, July, pp. 236–243.
17.
Singh, P. J., and Onuschak, A. D., 1984, “A Comprehensive, Computerized Method for Twin-Screw Rotor Profile Generation and Analysis,” Proceedings of the 1984 International Compressor Engineering Conference at Purdue, West Lafayette, IN 47907, July, pp. 519–527.
18.
Singh, P. J., and Patel, G. C., 1984, “A Generalized Performance Computer Program for Oil Flooded Twin-Screw Compressors,” Proceedings of the 1984 International Compressor Engineering Conference at Purdue, West Lafayette, IN 47907, July, pp. 544–553.
19.
Singh, P. J., and Schwartz, J. R., 1990, “Exact Analytical Representation of Screw Compressor Rotor Geometry,” Proceedings of the 1990 International Compressor Engineering Conference at Purdue, West Lafayette, IN 47907, July, pp. 925–937.
20.
Vinogradov
A. N.
,
Volodichev
S. A.
,
Kanyshev
G. A.
,
Konstantinov
V. E.
, and
Kuryshkin
N. P.
,
1986
, “
Calculation of The Geometrical Parameters of Screw Compressors
,”
Chemical and Petroleum Engineering
, Vol.
22
, No.
9–10
, pp.
493
495
.
21.
Zhang, L., and Hamilton, J. F., 1992, “Main Geometric Characteristics of The Twin Screw Compressor,” Proceedings of the 1992 International Compressor Engineering Conference at Purdue, West Lafayette, IN 47907, July, pp. 449–456.
22.
Zhang, L., and Hamilton, J. F., 1990, “Development of Sealing Line Calculation in Twin Screw Compressors,” Proceedings of the 3rd International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, Honolulu, HI, April.
This content is only available via PDF.
You do not currently have access to this content.