Optimum Design of Rectangular Micro Heat Exchangers

In this work a rectangular micro-heat exchanger with constant hydraulic diameter at various aspect ratios was considered and its pressure drop and thermal parameters versus pumping power in laminar flow at constant heat flux of 0.3 MW/m2 were analyzed and compared. Also, the effect of temperature-dependent fluid properties (viscosity and conductivity coefficient) on the pressure drop and thermal resistance of micro heat exchanger were investigated. Finally, a new criterion, based on pumping power and transmitted heat per temperature gradient, was proposed as a tool to optimize the aforementioned micro-heat exchanger.