TURBULENT HEAT TRANSFER IN A CIRCULAR TUBE WITH VISCOUS DISSIPATION

Abstract

The problem of developed turbulent conveclive heat transfer with viscous dissipation is considered for flow in a circular tube. Two cases are considered, Prandtl number equal to unity and large Prandtl number. For Prandtl number equal to unity, an exact expression for the recovery factor is presented which accounts for the radial variation in velocity profile. This exact expression is evaluated using the turbulent logarithmic velocity distribution. For large Prandtl numbers, a general asymptotic expansion for the recovery factor is determined which includes both wall and core contributions. A comparison of these results suggests that the large Prandtl number formula found for the recovery factor should be accurate for all Prandtl numbers greater than about unity.