壁面温度控制对平板边界层影响的数值研究

通过对零压力梯度的平板边界层流动施加温度控制，展开壁面温度控制对平板层流边界层和湍流边界层影响的研究，探索温度控制对平板转捩雷诺数和壁面摩擦阻力的影响规律。采用带有转捩模式的三方程湍流模型对平板边界层流动进行数值模拟，重点考察了壁面摩阻系数、平板转捩雷诺数、湍流边界层流动随壁面温度变化的规律。计算结果表明在壁面温度从288 K 增大到432 K 时，边界层转捩雷诺数增大约36%，表面摩擦阻力减少约9.6%。研究分析表明：加热控制使层流区域温度边界层内粘性作用增强，雷诺切应力和湍动能减小，流动更加稳定；而湍流区域边界层内粘性底层中速度梯度和粘性切应力减小，导致壁面处摩擦切应力减小。因此壁面加热控制可以延迟边界层转捩，减小湍流区摩阻系数，并减小平板摩擦阻力。

Numerical simulation of wall temperature control influence on flat plate boundary layer

To investigate the influence of wall temperature control on flat-plate laminar flow boundary layer and turbulent flow boundary layer, and to explore the influence law of temperature control on flat-plate transition Reynolds and wall frictional resistance,wall temperature control is carried out on flat plate flow boundary with zero pressure gradient .Flat plate boundary-layer flow is simulated numerically using a three-equal turbulent model with transition model,and influence of wall temperature control on wall friction drag coefficient, boundary layer transition and turbulent boundary layer is considered mainly.Numerical results indicate that boundary-layer transition Reynolds number has increased by almost 36%,and the wall friction drag has decreased by almost 9.6% when increasing wall temperature to 432 K from 288 K.The research shows that with wall heating,air’s viscous effect in the temperature boundary layer of laminar flow, is enhanced, Reynolds shear stress and turbulent kinetic decreased,and the flow is more stabilized;and in the viscous sublayer of turbulent flow,velocity gradient and viscous shear stress decreased, then wall ’s friction shear stress is minished. Therefore,boundary-layer transition could be delayed,and friction drag coefficient of turbulent zone and friction drag of flat plate could be reduced by wall heating control.