Gas cooling heat transfer coefficient for $CO_2$-PEC9 mixture under supercritical condition

초임계조건에서 $CO_2$-PEC9 혼합물의 물성예측을 통한 냉각 열전달특성 연구

  • Yun, Rin (Department of Mechanical Engineering, Hanbat National University)
  • 윤린 (한밭대학교 기계공학과)
  • Published : 2009.06.25

Abstract

Due to environmental concerns $CO_2$ has been reintroduced as a potential candidate to replace HFCs in refrigeration systems. Oils are always required in a vapor-compression cycle, and thus actual working fluid in the system is $CO_2$-oil mixtures even though the oil concentrations are low at the heat exchangers and the expansion device. The cooling heat transfer coefficients for $CO_2$-oil mixtures under supercritical condition are required to designing of the gas cooler in the $CO_2$ refrigeration system properly. In the present study, the gas cooling heat transfer coefficients for $CO_2$-PEC9 was estimated by using the Gnileinski correlation, and the Kim and Ghajar model through the previous prediction models for the thermo-physical properties of $CO_2$-oil mixture. The Gnileinski correlation was used when the oil wt.% in the mixture is less than 1.0, and for the higher oil concentration the Kim and Ghajar model was applied. The estimated results agree with the experimental results conducted by the Dang et al.

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