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为了得到不同流型下的换热性能 ,以R134a为工质对两种不同微肋几何结构的三维水平内微肋管进行了实验研究 ,通过可视化措施对流型及其转换进行了观测 .结果表明 :在Soliman流型图上 ,三维内微肋管环状流的分界线较之于光管向左平移了一段距离 ,即环状流与波状流的转换判据由Fr等于 7减小到Fr等于 2 .在较低的蒸汽流速和较低的干度下 ,三维内微肋管仍能维持环状流的状态 .环状流区的实验数据回归的换热关联式与实验值的最大偏差在± 2 5%以内
In order to obtain the heat transfer performance under different flow regimes, three-dimensional horizontal micro-finned tubes with different micro-rib geometries were experimentally studied with R134a as the working fluid, and the flow pattern and its transformation were observed through visualization. : On the Soliman flow pattern, the dividing line of three-dimensional micro-finned tube annular flow translates to the left by a distance from the light pipe, that is, the conversion criterion of annular flow and wavy flow decreases from Fr = 7 to Fr Equal to 2. The three-dimensional micro-finned tube still maintains the annular flow at lower steam velocities and lower dryness.The experimental data of the annular flow zone regress the maximum deviation of the heat transfer correlation from the experimental value Within ± 2 5%