水平管内冷凝换热实验研究

Experimental Study on Condensation Heat Transfer Inside Horizontal Tubes

研究了R410A在光管和1EHTa管内的冷凝换热特性,其饱和温度为318 K,并分析了质量流速与干度对冷凝换热特性的影响。依据Cavallini提出的流形图对实验数据进行流态的划分,发现光管和1EHTa管内部流态均位于重力控制的分层、分层波浪流流态,即ΔT-dependent。在实际观测中发现光管和1EHTa管内部冷凝流态主要集中在分层、分层波浪流。在部分干度和流速下出现半环形、环形流态。其中,1EHTa管在较高干度和流速下出现的半环形、环形流态。在实验流速范围内光管和1EHTa管换热性能,并未随着流速的增加而显著增加。1EHTa管的冷凝换热系数比光管大1.12~1.88倍。干度的增加对两种管子的换热性能均有提升,并且对1EHTa管的提升较为明显。

An experimental investigation of heat transfer coefficient and flow pattern during condensation of R410 A inside a smooth tube and a new developed enhanced tube 1 EHTa was conducted in this paper. According to the flow pattern map of Cavallini, all flow patterns in this research belong to the stratified flow and stratified wave flow which controlled by gravity, that is, ΔT-dependent. The experiment result shows that the flow patterns in smooth tube and 1 EHTa tube are mainly concentrated in stratified flow and stratified wave flow. And it is also found that semi-annular flow and annular flow patterns appeared at high vapor quality and mass flux in 1 EHTa tube. In addition, the condensation heat transfer performance of the two test tubes showed a slightly increase with the increase of the mass flux. The condensation heat transfer coefficient of 1 EHTa tube is 1.12—1.88 times larger than that of smooth tube. The increase of vapor quality can improve the condensation heat transfer performance of the two tubes, especially of the 1 EHTa tube.