Total Temperature Measurements of Gaseous Flow at Micro-Tube Outlet

This paper presents experimental results on heat transfer characteristics of gaseous flow in a micro-tube with constant wall temperature. The experiment was performed for nitrogen gas flow through a micro-tube with 166 micro meters in diameter and 50mm in length. The wall temperature was maintained at 305K, 310K, 330K and 350K by circulating water around the micro-tube, respectively. The stagnation pressure is chosen in such a way that the exit Mach number ranges from 0.1 to 1.0. The outlet pressure was fixed at the atmospheric condition. The total temperature at the outlet, the inlet stagnation temperature, the mass flow rate, and the inlet pressure were measured. The numerical computations based on the Aribitary - Langrangian - Eulerian (ALE) method were also performed for the same cases of the experiment for validation of numerical computation. The both results are in excellent agreement. The total temperatures obtained by the present study are slightly higher than those of the incompressible flow. This is due to the additional heat transfer near the micro-tube outlet caused by the temperature decrease due to the energy conversion into the kinetic energy. A quantitative correlation for the prediction of the heat transfer rate of the gaseous flow in a micro-tube was proposed.