内置双旋线换热管内流动与传热数值模拟

Numerical Simulation on Flow and Heat Transfer for the Tube Inserted with Double-Spiral-Line

采用数值计算方法,以水为流动介质,分别对内置双旋线外径为9 mm、12 mm、15 mm、18 mm的换热管内流体流动与传热特性进行模拟分析,结果表明:管内流体呈规律性三维螺旋流动,提高了管壁附近流体的周向速度和径向速度,加剧了管壁滞留层流体的扰动及与中心区域流体的混合;随着双旋线外径增大,流动阻力系数f随之增加;内置双旋线换热管的协同数均大于光管,综合性能评价指标PEC值可达1.8,说明内置双旋线换热管具有良好的综合换热性能。

A three-dimensional analysis on flow and heat transfer of the tube inserted with the double-spiral-Une was performed by numerical simulation.The outer diameter of the double-spiral-line was set as 9 mm.12 mm,15 mm,18 mm respectively.The results showed that the fluid presented the three-dimensional helical flow in the tube inserted with double-spiral-line,the circumferential and the radial velocity of fluid near tube wall was improved to some extent.Thus the retention layer of the tube wall boundary layer was disturbed vigorously,the core area of fluid was mixed completely with the retention layer.With the increasing of the outer diameter of double-spiral-line,the friction factor increased obviously.The field synergy number of the tube inserted with double-spiral-line was much higher than plain tube,the heat transfer tube inserted with double-spiral-line can improve the flow and heat transfer performance effectively,the value of performance evaluation criterion(PEC)reached to 1.8.