Boiling in Microchannels with Refrigerant Mixtures
Experiments were conducted to investigate the saturated flow boiling heat transfer characteristics in single micro tube using environmentally acceptable refrigerant mixtures R32 and R134a. Local heat transfer coefficient was measured and boiling heat transfer mechanisms were discussed for a range of heat flux (3-65 kW/m2) , mass flux (860-4816 kg/m2•s) and quality (0-0.9). These characteristics indicated that the local heat transfer coefficient was greatly dependent of heat flux and independent of mass flux and quality in the nucleate boiling regime, which was oppsite to that in forced convection regime, and deterioration of boiling heat transfer occurred in the local dry-out regime. In addition, a correlation for nucleate dominant boiling in micro tube was developed ,which included the effects of heat flux and fluid property and showed some success with the data of this study within a 20% random error band.
Shengyi Li, Yingchun Liu, Rongbo Zhu, Hongguang Li, Wensi Ding
Z. C. Hu et al., "Boiling in Microchannels with Refrigerant Mixtures", Applied Mechanics and Materials, Vols. 34-35, pp. 576-581, 2010