化工学报2016，Vol.5Issue(5)：1748-1754,7.DOI:10.11949/j.issn.0438-1157.20151306
水平圆形与方形微小通道内R134a冷凝数值模拟
Numerical simulation of condensation in horizontal circular and square minichannels using R134a
摘要
Abstract
Heat transfer and pressure drop characteristics of condensation for R134a at saturation temperature of 320 K inside horizontal circular and square minichannels were investigated numerically. The results indicated that the heat transfer coefficients and frictional pressure drop gradients increased with mass flux and vapor quality, while the pressure drops decreased with increasing vapor quality atx>0.85. Compared with the circular tube, the square channel with the same perimeter as the corresponding circular tubes can enhance heat transfer coefficients and increase the pressure losses. The numerical results agreed well with the well-known empirical correlations for condensation. A thicker liquid film was obtained at the bottom of the round tube, while the liquid film for the square channel accumulated at the bottom and the middle top of the channels at lower vapor quality. The proportion of the thinner liquid film region, which corresponded to a higher heat transfer coefficient, increased with increasing vapor quality, leading to a higher heat transfer coefficient at higher vapor quality. The liquid film thicknesses in square channels were lower than that in circular channels, thus enhancing the heat transfer.关键词
凝结/微小通道/数值模拟/传热/压降Key words
condensation/minichannels/numerical simulation/heat transfer/pressure drop分类
能源科技引用本文复制引用
张井志,李蔚..水平圆形与方形微小通道内R134a冷凝数值模拟[J].化工学报,2016,5(5):1748-1754,7.基金项目
浙江省自然科学基金项目(LZ13E060001) （LZ13E060001）
国家自然科学基金国际合作项目(51210011).supported by the Natural Science Foundation of Zhejiang Province (LZ13E060001) and the National Natural Science Foundation of China (51210011). （51210011）
