过渡流下叉排翅片列三维传热特性的研究

Study on 3D Numerical Analysis of Heat Transfer Performence for Offset Strip Fin in Transitional Flow

叉排翅片是一种用在换热器表面排列紧凑而高性能的结构,应用极其广泛。目前国内外研究虽获得了大量实验数据和二维(2D)数值结果,但是对实际结构和边界条件下的三维(3D)数值研究涉及较少。为了进一步加深对叉排翅片列的3D数值模拟传热特性的研究,建立了叉排翅片3D数值模型,与实验结果、实验关联式进行了比较,分析了一些模拟与实验误差的因素,验证了实际边界条件下的3D数值模型,并进行了叉排翅片表面传热特性的分析。结果表明,存在一个非定常层流区且其流场在翅片区以外不稳定而在翅片区以内稳定,同时非定常层流区的传热性能比定常层流区的好。

The offset strip fin geometry is one of the highest performance compact heat exchanger surface and is commonly used in many applications. Considerable experimental data and two--dimensional （2D） numerical analyses are reported in the present literature. However, no full three-dimensional （3D） numerical investigation with realistic geometry and boundary conditions are reported. Computational model ofihe offset strip fin is set upin order to further study the heat transfer peptone based on 3D numerical simulation. The present results are compared with reported 3D numerical results and experimental results. And then the factors for errors between simulations and experiments will be analyzed. After the present computational model is validated with the realistic boundary conditions, 3D numerical analyses of mechanisms of heat transfer enhancement are carried out for offset strip fins. Results？show that one more flow region named as the unsteady laminar ftow region in which flow field becomes unsteady beyond the fin region but is steady within the fin region. Compared with the laminar ftow region, the heat transfer performance in the unsteady laminar ftow region is higher.