Temperature Distribution in the Entrance Region of a Circular Pipe

Abstract

Temperature distributions for the flow of air flowing through the entrance region of a heated pipe have been investigated. The local temperatures of the flow were measured by a resistance thermometer. In the region of laminar boundary layer, thermal boundary layer was calculated by solving approximately the energy integral equation, and the analytically produced results were found to agree closely with the experimental ones. At the turbulent boundary layer, there are some disagreements between the experimental results and the theoretical values calculated by Latzko's and Deissler's analytical solutions. From the t⁺, y⁺ relationship a slight correlation can be found between the temperature profiles in the turbulent boundary layer and those in the long pipe. The buoyancy effects in the entrance region were investigated experimentally.