$CO_2$ 단열 모세관내 유동 특성

• Roh, Geon-Sang (Department of Refrigeration and Air-conditioning Engineering, Tong Myong Univ.) ;
• Son, Chang-Hyo (School of Mechanical Engineering, Pukyong National Univ.)
• 노건상 (동명대학교 냉동공조공학과) ;
• 손창효 (부경대학교 기계공학부)
• Published : 2008.12.30
• 85 5

Abstract

In this paper, flow characteristics of an adiabatic capillary tube in a transcritical $CO_2$ have been investigated employing the homogeneous model. The model is based on fundamental equations of mass, energy and momentum which are solved simultaneously. Two friction factors(Churchill) and viscosity(McAdams) are comparatively used to investigate the flow characteristics. Supercritical and subcritical thermodynamic and transport properties of $CO_2$ are calculated employing EES property code. Flow characteristics analysis of $CO_2$ adiabatic capillary tube is presented to offer the basic design data for the operating parameters. The operating parameters considered in this study include inlet temperature and pressure of an adiabatic capillary tube, evaporating temperature and inner diameter tube. The main results were summarized as follows : inlet temperature and pressure of an adiabatic capillary tube, evaporating temperature, mass flowrate and inner diameter of $CO_2$ adiabatic capillary tube have an effect on length of an adiabatic capillary tube.

References

1. Sawalha, S., "Using CO2 in supermarket refrigeration". ASHRAE J. 47 (8), 2005, pp. 26-30
2. EES: Engineering Equation Solver, 2006. fChart Software Inc
3. Hihara E. and Tanaka S. "Boiling heat transfer of carbon dioxide in horizontal tubes". Preliminary proceedings of the 4th IIR-Gustav Lorentzen conference on natural working fluids at Purdue, 2000, pp. 279-284
4. Bittle, R. R. and Pate, M. B., "Theoretical model for predicting adiabatic capillary tube performance with alternative refrigerants", ASHRAE Transactions, Vol. 102, No. 2, 1996, pp. 52-61
5. Bansal, P. K. and Rupasinghe, A. S., "An empirical model for sizing capillary tubes", Int. J. Refrigeration, Vol. 19, No. 8, 1996, pp. 497-505 https://doi.org/10.1016/S0140-7007(96)00044-8
6. Wilson, I. and Maier, D., "Carbon dioxide for use as a refrigerant. In: Refrigeration Science and Technology", Proceedings, IIR-IRHACE Conference, Innovative Equipment and Systems for Comfort and Food Preservation. The University of Auckland, 2006, pp. 305-311
7. Agrawal, N. and Bhattacharyya, S., "Adiabatic capillary tube flow of carbon dioxide in a transcritical heat pump cycle", Int. J. of Energy Research, Vol. 31, 2007, pp. 1016-1030 https://doi.org/10.1002/er.1294
8. Churchill, S. W., "Frictional equation spans all fluid flow regimes, Chem. Eng., Vol. 84, 1977, pp. 91-92
9. Bansal, P. K. and Rupasinghe, A. S., "An homogenous model for adiabatic capillary tubes", Applied Thermal Engineering, Vol. 18, No. 3-4, 1998, pp. 207-219 https://doi.org/10.1016/S1359-4311(97)00016-1
10. Yun, B., Park, H. Y., Yoo, K. C. and Kim, Y. C., "Air-conditioner cycle simulation using tube-by-tube method", Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol. 11, No. 4, 1999, pp. 499-510