Characteristics of the Dimensionless Temperature in Tubes With Axial Wall Heat Conduction

Abstract

Characteristics of the dimensionless temperature, θ, are performed to investigate in laminar circular tube flow by numerical simulation with the presence of axial heat conduction. A uniform heat flux is imposed on outside wall surface. The smallest inner diameter of circular tube is only 200 μm. The heat transfer and flow can be described by traditional Navier-Stokes and energy equations. The results shows that θ is identical under the condition of different specified heat flux on the outside wall surface at the same Peclet number. Furthermore, the dimensionless temperature at the tube entrance θ(0) is independent on wall thickness, tube material, working fluid and boundary condition. Hence, the dimensionless temperature at the tube entrance θ(0) is only a function of Peclet number and the corresponding correlation of θ(0) in circular tube is obtained from numerical results and validated by other available cases. Moreover, the correlation of θ(0) is also applied with different cross-sectional shapes of heated solid surface when inner diameter of fluid region is not less than 2.0 mm.