Single phase heat transfer analysis of water and R134a refrigerant （liquid phase） has been carried out using CFD （Computational fluid dynamics） approach for rectangular channel with smooth wavy fin. Colburnj facto...Single phase heat transfer analysis of water and R134a refrigerant （liquid phase） has been carried out using CFD （Computational fluid dynamics） approach for rectangular channel with smooth wavy fin. Colburnj factor and Fanning friction factorf are predicted for wavy fin. The correlations are developed at Reynolds number range of 100-15,000. The effect of fin geometry （fin spacing, fin height, wave height and wave length） on the enhanced heat transfer and pressure drops are investigated. Results show that there is no significant variation off factor for water and liquid R134a at constant Reynolds number. However variations inj factor were observed at constant Reynolds number. Colburnj factor and Fanning friction factorfcorrelations are proposed in terms of Re and geometry parameters （h/s, a/s, L/a） for water and liquid refrigerant R134a in the present study. Two separate equations are proposed for the low and high Re regions i.e. between Re of 100-1,000 and Re of 1,000-15,000.展开更多
The effects induced by streamwise conduction on the thermal characteristics of forced convection for single-phase liquid flow in rectangular microchannel heat sinks under imposed constant wall temperature have been st...The effects induced by streamwise conduction on the thermal characteristics of forced convection for single-phase liquid flow in rectangular microchannel heat sinks under imposed constant wall temperature have been studied. By employing the fin approach in the first law of analysis, models with and without streamwise conduction term in the energy equation were developed for hydrodynamically and thermally fully-developed flow under local thermal non-equilibrium for the solid and fluid phases. These two models were solved to obtain closed form analytical solutions for the fluid and solid temperature distributions and the analysis emphasized details of the variations induced by the streamwise conduction on the fluid temperature distributions. The effects of the Peclet number, aspect ratio, and thermal conductivity ratio on the thermal characteristics of forced convection in microchannel heat sinks were analyzed and discussed. This study reveals the conditions under which the effect of streamwise conduction is significant and should not be neglected in the forced convective heat transfer analysis of microchannel heat sinks.展开更多
文摘Single phase heat transfer analysis of water and R134a refrigerant （liquid phase） has been carried out using CFD （Computational fluid dynamics） approach for rectangular channel with smooth wavy fin. Colburnj factor and Fanning friction factorf are predicted for wavy fin. The correlations are developed at Reynolds number range of 100-15,000. The effect of fin geometry （fin spacing, fin height, wave height and wave length） on the enhanced heat transfer and pressure drops are investigated. Results show that there is no significant variation off factor for water and liquid R134a at constant Reynolds number. However variations inj factor were observed at constant Reynolds number. Colburnj factor and Fanning friction factorfcorrelations are proposed in terms of Re and geometry parameters （h/s, a/s, L/a） for water and liquid refrigerant R134a in the present study. Two separate equations are proposed for the low and high Re regions i.e. between Re of 100-1,000 and Re of 1,000-15,000.
文摘The effects induced by streamwise conduction on the thermal characteristics of forced convection for single-phase liquid flow in rectangular microchannel heat sinks under imposed constant wall temperature have been studied. By employing the fin approach in the first law of analysis, models with and without streamwise conduction term in the energy equation were developed for hydrodynamically and thermally fully-developed flow under local thermal non-equilibrium for the solid and fluid phases. These two models were solved to obtain closed form analytical solutions for the fluid and solid temperature distributions and the analysis emphasized details of the variations induced by the streamwise conduction on the fluid temperature distributions. The effects of the Peclet number, aspect ratio, and thermal conductivity ratio on the thermal characteristics of forced convection in microchannel heat sinks were analyzed and discussed. This study reveals the conditions under which the effect of streamwise conduction is significant and should not be neglected in the forced convective heat transfer analysis of microchannel heat sinks.
