流道内错列倒置柔性体运动及强化传热分析

Analysis of motion and heat transfer enhancement of staggered inverted flexible bodies in flow channels

以换热器流道内强化换热为目的,建立了带有错列倒置柔性扰流体的矩形流动换热模型,通过任意拉格朗日欧拉(ALE)方法模拟研究了不同抗弯强度和布置间距的柔性扰流体对通道内流动和换热的影响。结果表明:不同抗弯强度的柔性体在相同流动工况下呈现出偏置、大振幅拍动和偏转拍动3种运动模式;与不设置扰流体的流动通道相比,柔性扰流体的3种拍动模式分别可使流动通道的平均Nu提高40.4%~70.6%、45.1%~83.5%和38.3%~75.1%;增大错列柔性体的竖向间距也可提高通道平均Nu,当量纲一竖向间距为0.7且柔性体处于大振幅拍动模式时,通道平均Nu达到最大值,比无扰流体通道提高85.8%,热效率系数提高6.5%。

For the purpose of heat transfer enhancement in the flow channel of heat exchangers,a rectangular flow heat transfer model with staggered inverted flexible disturbing bodies is established,and the effects of flexible disturbing bodies with different bending strengths and arrangement spacing on the flow and heat transfer in the flow channel are simulated by arbitrary Lagrangian-Euler(ALE)method.The results show that the flexible body with different bending strengths presents three motion modes under the same flow condition:bias,large amplitude flapping and deflection flapping.Compared with the flow channel without disturbing bodies,the three flapping modes of flexible disturbing bodies can increase the average Nu in the flow channel by 40.4%-70.6%,45.1%-83.5%and 38.3%-75.1%,respectively.Increasing the vertical spacing of the staggered flexible bodies can also increase the average Nu in the flow channel.When the dimensionless vertical spacing is 0.7 and the flexible bodies are in large amplitude flapping mode,the average Nu in the flow channel reaches the maximum value,which is 85.8%higher than that in the non-disturbed flow channel,and the thermal efficiency coefficient is 6.5%higher than that in the non-disturbed flow channel.