涡结构对对流传热影响的实验和模拟研究

Experiment and simulation of vortex effect on convective heat transfer

利用计算流体动力学(CFD)模拟和粒子图像测速技术(PIV)实验相结合的方法研究了一个类似于板式换热器的模型在内部转子旋转的条件下,产生涡结构,提高传热效果的过程。首先采用PIV技术测定了在一定流量不同转速的条件下,模型中流场的变化。然后,运用CFD方法计算流动传热过程。计算的流场结构和PIV测定流场结构较为一致,显示出采用计算方法的可行性和有效性。计算结果表明,与没有转子转动相比,转子转动会使流场中出现涡结构,并且发生明显的扰乱。这优化了模型中流场结构,强化了换热效果。流动换热过程中,在压力损失的增加不变的条件下,换热效果得到了极大地提高。而且转速越快,换热效果提高越明显。

The approach of CFD simulation combined with PIV experiment is used to study the process,which results in vortex and improves the efficiency of convective heat transfer in the plate heat exchanger model on the condition of the rotation of the rotor.Firstly,flow field change in the model under different rotate speeds is obtained by PIV.Then the CFD software is run to simulate the process of the flow and heat transfer.The flow structurerun by CFD is consistent with that obtained by PIV,which shows the validity of the computational method.Thedatum from computation demonstrates that the rotation of the rotor leads to the appearance of vortex and turbulence of flow field,which optimizes the flow pattern and enhance the heat transfer.When the increase of pressure drop is constant,the heat transfer performance will be improved greatly through the process.The faster the rotor rotates,the more improvement there will be.