The liquid flow and conjugated heat transfer performance of single-phase laminar flow in rectangular microchannels equipped with longitudinal vortex generators (LVGs) are numerically investigated. Deionized-water with temperature-dependent thermo-physical properties is employed to conduct the simulations. Three dimensional simulations are performed using an open-source flow solver based on finite volume approach and SIMPLEC algorithm. Five different configurations of the microchannel with different angles of attack of the LVGs are considered. Simulation results are compared with available experimental data and a deviation below 10% is achieved. The results show that there is a 2-25% increase in the Nusselt number for microchannels with LVGs, while the friction factor increased by 4-30%, for Reynolds number ranged from 100 to 1100. Except one at Re=100, the overall performance of the all configurations of microchannels with LVGs is higher than one. Highlights• Temperature-depended thermo-physical properties is used to improve the numerical results.• Thermo-hydraulic performance of the microchannels with LVGs is studied in details.• Higher heat transfer enhancement is observed at higher Reynolds numbers.• Microchannels with LVGs cause higher pressure loss in the device.• The overall efficiency of the microchannels with LVGs is calculated.

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A detailed evaluation of the performance parameters in the laminar flow regime with regard to the enhancement of heat transfer using winglet type vortex generators has been accomplished in this study. Three dimensional numerical studies of flow structure and laminar convectionheat transfer are performed in a plate fin heat exchanger with longitudinal vortex generators (LVGs) in present paper. The Effects of common flow up and common flow down pairs of vortices produced by LVGs with two different shapes of the winglets, a pair of rectangular winglet (RWP) and a pair of delta winglet (DWP), are studied at various Reynolds numbers. The results show that effect of LVGs could effectively enhance the heat transfer of the heat exchanger. According to the non-dimensional defined parameter for evaluation of performance, (Num/Num,0)/(f/f0), the channel with DWP shows better overall performance than RWP. The common flow down configuration of DWP shows a better overall performance at Reynolds numbers lower than 720 and common flow up configuration of DWP shows a better overall performance at Reynolds numbers more than 720; also, the common flow down configuration shows a better overall performance than the common flow up configuration for RWP.