Heat transfer for turbulent flow in a circular tube with uniform suction or injection

The results of calculations of mean and fluctuating heat transfer characteristics in a turbulent flow of liquid through a circular tube with permeable walls are presented. The results were obtained with the use of six differential equations for the description of turbulent momentum and the heat transfer mechanism. The calculations were conducted for air (Pr = 0.7) over the Reynolds numbers of 10,000 to 400,000 and suction (injection) rates of -0.2 to 0.02. The effect of suction and injection on the velocity and temperature distributions, temperature fluctuations, turbulent heat flux, and turbulent Prandtl number is shown. It has been established that the effects of strong suction (injection) on the hydrodynamic and thermal characteristics are different; this fact being due to the apperance of high positive (for suction) and negative (for injection) pressure gradients. In the case of strong suction, a substantial change in Pr(t) over the tube cross-section is observed. The results of Stanton number calculations for the region far from the inlet cross-section are well correlated to give a relative heat transfer law.