Heat Transfer Correlation during Gas-Cooling Process of Carbon Dioxide in a Horizontal Tube

  • Kang Byung-Ha (School of Mechanical and Automative Engineering, Kookmin University) ;
  • Choi Yi-Cheol (Graduate School, Kookmin University) ;
  • Kim Suk-Hyun (School of Mechanical and Automative Engineering, Kookmin University)
  • Published : 2006.03.01


The characteristics of heat transfer and pressure drop have been investigated experimentally during gas-cooling process of carbon dioxide. The results of this study are useful information in the design of a heat exchanger of $CO_2$ refrigerator. The test section consists of 6 series of copper tube, 4.15 and 2.18mm ID, respectively. The inlet temperature, the operating pressure, and the mass flux are varied in the range of $80{\sim}120^{\circ}C,\;{7\sim}10MPa,\;and\;400{\sim}1,900kg/m^2s$, respectively. The heat transfer coefficient of $CO_2$ is affected by temperature, inlet pressure, and mass flux of $CO_2$. At the maximum HTC, the temperature of $CO_2$ nearly accords with the psuedocritical temperature. It is found that the pressure drop is substantially affected by mass flux and inlet pressure of $CO_2$ . The results have been compared with those of previous work. The heat transfer correlation at the gas-cooling process has been also suggested which predicts within the error of 20%.



  1. Hwang, Y. and Radermacher, R., 1999, Experimental investigation of the $CO_2$ refrigeration cycle, ASHRAE Trans., Vol.105, Part 1, Paper No. CH-99-22-2
  2. Yoon, S. H., 2002, Studies on the characteristics of evaporation and supercritical gas cooling heat transfer of carbon dioxide, Ph. D. Thesis, Seoul National University, Seoul, Korea
  3. Yin, J. M., Bullard, C. W. and Hrnjak, P. S., 2000, Design strategies for R744 gas cooler, Preliminary Proceedings of the 4th IIRGustav Lorentzen Conference on Natural Working Fluids at Purdue, July 25-28, USA, pp.315-322
  4. Hwang, Y. and Radermacher, R., 1998, Theoretical of carbon dioxide refrigeration cycle, Int. J. HV AC&R Research, Vol4, No.3, pp, 245-263 https://doi.org/10.1080/10789669.1998.10391403
  5. Krasnoshchekov, E. A., Kuraeva, I. V. and Protopopov, V. S., 1970, Local heat transfer of carbon dioxide atsupercritical pressure under cooling conditions, High Temperature Institute (Translated from Teplofizika Vysokikh Temperatur), Vol. 7, No.5, pp.856-862
  6. Petrov, N.E. and Popov, V. N., 1985, Heat transfer and resistance of carbon dioxide be-ing cooled in the supercritical region, Thermal Engineering, Vol. 32, No.3, pp. 131-134
  7. Fang, X., Bullard, C.W.and Hrnjak, P.S., 2001, Modeling and analysis of gas coolers, ASHRAE Trans., Vol. 107, Part 1. Paper-No, 4411
  8. Olsen, D. A., 2000, Heat transfer of supercritical carbon dioxide flowing in a cooled horizontal tube, Preliminary Proceedings of the 4th IIR-Gustav Lorentzen Conference on Natural Working Fluids at Purdue, July 25-28, USA, pp. 251-258
  9. Pitla, S. S., Groll, E. A. and Ramadhyani, S., 2001, Convective heat transfer from in-tube cooling of turbulent supercritical carbon dioxide: Part 2-Experimental data and numerical predictions, Int. J. HV AC&R Research, Vol. 7; No.4, pp.367-382 https://doi.org/10.1080/10789669.2001.10391281
  10. Incropera, F. P. and DeWitt, D. P., 1990, Introduction to Heat Transfer, 2nd ed., John Wiley & Sons, New York, pp. 455-460