Heat Transfer Characteristics of Gaseous Flows in a Microchannel and a Microtube with Constant Wall Temperature

Abstract

Two-dimensional compressible momentum and energy equations are solved to obtain the heat transfer characteristics of gaseous flows in a microchannel and in a microtube with constant wall temperature, whose temperature is lower than the inlet temperature (cooled case). 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 temperature, which ranges from 250 to 290 K. The bulk temperature based on the static temperature and the total temperature of the cooled case are compared with those of the heated case and also compared with temperatures of the incompressible flow in a conventional-sized channel. Identical heat transfer coefficients are obtained for both cooled and heated cases of incompressible flow. However, in the case of gaseous flow, different heat transfer coefficients are obtained for each cooled and heated case. A correlation for the prediction of the heat transfer rate of the gaseous flow in a microchannel and in a microtube is proposed.

Effects of viscous heating, fluid property variation, velocity slip, and temperature jump on convection through parallel plate and circular microchannels

“…According to this figure, plots of Nu show the same trend as those of Po. As expected, based on limiting cases from previous studies [25][26][27][28][29][30][31][32][33][34][35], Nu decreases with either Kn or Br.…”

Revisited analysis of gas convection and heat transfer in micro channels: Influence of viscous stress power at wall on Nusselt number

“…We insist on this point because some authors did not take into account the temperature jump condition when a heat ux is imposed on a wall to determine the wall temperature. the viscous dissipation (heat source) [45,46], the work of the viscous forces at the wall in the presence of dynamic slip [27,47,48], the variation of the physical properties with temperature [49,50], the dominant thermal and dynamical axial diusions at the inlet and outlet boundaries when Re and P e are less than unity, the heat conduction in the walls (conjugate heat transfer) because they are usually thicker than the channel and more conducting than the gas [51].…”

“…V g = 0 (45) where all the variables with subscript g are functions of X at Y = 1 4 , on the gas side.…”

Numerical Investigation of Effects of Ramification Length and Angle on Pressure Drop and Heat Transfer in a Ramified Microchannel

“…The computational fluid dynamics (CFD) of microchannels has been exploded recently with the improvement computer technique and the suitability of the used models to predict the results (Chao et al 2005;Renksizbulut et al 2006;Hong and Asako 2007;Kuddusi and Cetegen 2009;Shojaeian and Dibaji 2010). The numerical technique in these studies is very important in order to approach the correct result.…”