高分子稀溶液极限减阻热入口段长度的求解

The calculation of the thermal entrance region for the maximal drag reduction of dilute polymer solution

在忽略黏性耗散影响的基础上,通过将减阻流体极限减阻时的速度分布和温度分布应用于湍流热边界层方程,推导出了湍流热边界层厚度的微分方程和热入口段长度的解析表达式.热入口段长度与管道半径成线性比例关系的结论,不仅反映出相比牛顿流体热入口段长度的增大,而且也为工程上估算高分子极限减阻的热入口段长度提供了理论依据.

Based on neglecting the influence of the viscous dissipation, the differential equation of calculating the thickness of turbulent thermal boundary layer and the analytical expression for the length of thermal entrance region were obtained by applying the velocity and temperature profiles of the maximal drag reduction to the turbulent thermal boundary layer equation. The conclusion of the linear relation between the length of the thermal entrance region and the pipe radius not only reflects the augment of the thermal entrance region corresponding to Newtonian fluid but also provides a theoretical basis for calculating the length of the entrance region in engineering.