Two-phase flow convective condensation of refrigerant mixtures under gas/liquid injection

Abstract

SUMMARYThe influence of gas/liquid injection on two-phase flow condensation heat transfer characteristics of some refrigerant mixtures in horizontal enhanced surface tubing is presented.Correlations were proposed to predict the impact of the gas/liquid injection on the heat transfer characteristics such as average heat transfer coefficient of R-507, R-404A, R-410A, and R-407C in twophase flow condensation inside enhanced surface tubing. The data also revealed that gas, liquid and gas/ liquid injection is beneficial at certain gas/liquid injection ratios to the heat transfer coefficient depending upon the Reynolds number and the condensation point of the refrigerant mixtures in question.It was also evident that the proposed condensation correlations and the experimental data were applicable to the entire heat and mass flux, investigated in the present study under gas/liquid injection conditions. The deviation between the experimental and predicted under gas/liquid injection were less than AE 10, for the majority of data.

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“…Wang's work concluded that heat transfer coefficients of R-410A and R-22 are comparable. Other results have been reported on two-phase flow characteristics inside smooth tube by Wijaya and Spatz [5] using R-22 and R-410A [1][2][3][4][5][6][7][8][9].…”

“…Study of the literature revealed, in addition to what has been reported by Sami et al [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], that Kim and Hyun [4] has investigated the nucleate boiling on several commercially available enhanced and smooth tubes using working fluids R-22, R-123, R-134a, R-407C and R-410A in water/ refrigerant geometry. Wang's work concluded that heat transfer coefficients of R-410A and R-22 are comparable.…”

“…To the author's knowledge, the studies reported by Sami et al [1,3] are the only existing studies on the boiling and condensation of alternatives refrigerants under gas/liquid injection inside internally and externally enhanced surfaces, such as double fluted tubes and air-fined tubes. As new alternatives such as R-507, R-404A, R-407B, and R-408A are considered as potential alternatives to R-502 in air-fined heat exchangers, the current research work has been done to enhance our understanding of the fluid flow boiling and heat transfer characteristics of these new alternative refrigerants inside enhanced micro-fins surface tubing.…”