Nucleate pool boiling and filmwise condensation heat transfer of R134a on the same horizontal tubes

作者：Ji Wen Tao; Numata Mitsuharu; He Ya Ling; Tao Wen Quan^*

来源：International Journal of Heat and Mass Transfer, 2015, 86: 744-754.

DOI：10.1016/j.ijheatmasstransfer.2015.02.020

• Pool boiling
• Condensing
• Heat transfer
• R134a
• Tube

Pool boiling and condensing heat transfer of R134a on one plain and three enhanced surfaces are experimentally investigated. The saturation temperature in pool boiling is 6 degrees C and condensing is 40 degrees C. The heat flux ranges from 8 to 86 kW/m(2). The enhanced tubes include integral-fin, pyramid and re-entrant cavity surface. The outside diameter of test tubes is 19 mm and the length of test section for boiling is 1100 mm and condensing is 1800 mm. Integral-fin tube has lower heat transfer coefficient in boiling and condensing. The deviations of experiment result and Owen or Webb models are within +/- 10% for integral-fin tube in condensing. Pyramid surface provides quite close heat transfer coefficient with re-entrant cavity surface in pool boiling and condensing at heat flux greater than 70 kW/m(2). The heat transfer performances of re-entrant cavity surface tube is the highest among the three enhanced tubes in either pool boiling or condensing at not high heat flux. The heat transfer coefficients can be 1.9-4.8 and 14.8-19.3 times those of a plain tube in pool boiling and condensing respectively. The decreasing rate of heat transfer coefficient for re-entrant cavity surface is also higher than pyramid surface in condensing. Literature survey on nucleate pool boiling and filmwise condensation is also conducted.

• 出版日期2015-7
• 单位西安交通大学