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Experimental study on convective boiling heat transfer for pure refrigerants and refrigerant mixtures in a horizontal tube

순수 및 혼합냉매의 원관내 증발열전달 실험

  • Sin, Ji-Yeong (Dept.of Mechanical Engineering, Graduate School of Seoul National University) ;
  • Kim, Min-Su (Dept.of Mechanical Engineering, Seoul National University) ;
  • 신지영 (서울대학교 대학원 기계공학과) ;
  • 김민수 (서울대학교 기계공학과) ;
  • Published : 1996.02.01

Abstract

Boiling heat transfer coefficients of pure refrigerants (R22, R32, R134a, R125, R290, and R600a) and refrigerant mixtures (R32/Rl34a, R290/ R600a, and R32/R125) are measured experimentally and compared with Chen's correlation. The test section is a seamless stainless steel tube with inner diameter of 7.7mm and uniformly heated by applying electric current directly to the tube. Heat fluxes range from 10 to 30kW$^2$. Mass fluxes are set to 424 ~ 742kg/m$^{2}$s for R22, R32, R134a, R32/R134a, and R32/Rl25 ; 265 ~ 583kg/m$^{2}$s for R290, R600a, and R290/R600a. Heat transfer coefficients depend strongly on heat flux at a low quality region and become independent as quality increases. Convective boiling term in the Chen's correlation predicts experimental data of the pure refrigerants fairly well (relative error of 12.1% for the data of quality over 0.2). The correlation for pure substances overpredicts the heat transfer coefficients for nonazeotropic refrigerant mixtures.

Keywords