圆管等壁温振荡流动对流换热理论研究

Theoretical study on heat transfer characteristics of oscillating flow in a circular tube

对等壁温边界条件下圆管内层流振荡流动对流换热问题进行理论推导。在随时间做正弦变化的速度入口条件下,经求解圆管内流体振荡时的能量方程,得到振荡流动圆管内温度场分布的解析解表达式,并利用Matlab对表达式进行直观表示。计算结果表明:等壁温边界条件下速度入口脉冲流动可引起温度随时间波动,波动随无量纲振荡频率和速度振荡幅度增加,换热效果加强,且速度振荡幅度和无量纲振荡频率存在协同作用。

The convective heat transfer problem in a circular tube under the equivalent wall temperature boundary conditions was theoretically derived. The analytic expression of the distribution of the temperature field in a circular tube was obtained by solving the energy equation of the fluid oscillation in a circular tube under the condition of the velocity entry of a sinusoidal variation with time with Matlab. The calculation results show that the temperature fluctuates with time under the constant wall temperature boundary condition. The heat transfer effect is strengthened with the increase of the dimensionless oscillation frequency. The effective heat transfer area in the tube increases with the increase of the amplitude of the velocity fluctuation, and the heat transfer effect is significantly stronger.