Heat Transfer Characteristics of Gaseous Flow in a Micro-Tube

Two-dimensional compressible momentum and energy equations are solved numerically to obtain the heat transfer characteristics of gaseous flow in a micro-tube with isothermal wall. The numerical methodology is based on the Arbitrary-Lagrangian-Eulerian (ALE) method. The stagnation temperature is fixed at 300 K and the computations were done for the wall temperatures of 305 K, 310 K and 350 K. The bulk temperature based on the static temperature is compared with that of the incompressible flow in a conventional sized tube. The static bulk temperature of the gaseous flow in a micro-tube decreases approaching to the outlet due to the energy conversion into the kinetic energy, when flow is fast. The total temperatures are also compared witht he bulk temperature of the incompressible flow in a conventional sized tube. The total temperature is slightly higher than the bulk temperature of the incompressible flow. This is due to the additional heat transfer near the outlet. A correlation for the prediction of the heat transfer rate of the gaseous flow in the micro tube is proposed.