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对高温导热油在螺纹管内流动和传热进行实验研究,结果表明:在层流区,螺纹管沿程阻力系数是相应光管的1.8~3.0倍,Nu数是相应光管的2.8~4.6倍。在湍流区,螺纹管沿程阻力系数是相应光管的3~4倍,Nu数是相应光管的1.8~3.8倍。应用FLUENT对螺纹管和光管进行三维数值模拟,结果表明在螺纹管流场的背流面存在回流区。与光管相比,螺纹管局部协同角的变化范围更大,且在凹槽左右的位置局部协同角接近90°,远离凹槽位置,局部协同角较光管有明显下降。
The experimental study on the flow and heat transfer of HTF in a screwed tube shows that in the laminar flow zone, the drag coefficient along the threaded pipe is 1.8-3.0 times that of the corresponding light pipe and the Nu number is 2.8-4.6 times that of the corresponding light pipe . In the turbulence area, the drag coefficient along the threaded pipe is 3 to 4 times that of the corresponding light pipe, and the Nu number is 1.8 to 3.8 times of that of the corresponding light pipe. The three-dimensional numerical simulation of the threaded pipe and the light pipe using FLUENT shows that there is a recirculation zone in the back flow surface of the pipe flow field. Compared with the light pipe, the local synergic angle of the threaded pipe changes more widely, and the local synergistic angle near the groove is close to 90 °, far away from the groove, and the local synergy angle is obviously lower than that of the light pipe.