A simple method for predicting bulk temperature from tube wall temperature with uniform outside wall heat flux

An empirical approach is proposed to estimate the bulk temperature in practical laminar tube flow. To examine the correlation, heat transfer in different types of tubes with wall conduction and uniform constant heat flux at tube outer wall surface is numerically investigated. The predictions from the proposed correlation match well with the numerical results in all the cases studied for air flow in the Pe range from 105 to 1032 and for water flow in the Pe range from 70 to 700. The method is further testified via comparison with experimental data and numerical results of mini (micro)-channel water flow available in literature.