Flow Resistance and Heat Transfer Characteristics of Air in a Cross Flow Micro Heat Exchanger

Flow resistance and heat transfer characteristics of air flowing through a cross flow micro heat exchanger of stainless steel were experimentally investigated. The hydraulic diameter of rectangular microchannels was of 240 microns and the heat exchanger was made up of four sheets of 29 channels. The transition from laminar to turbulent flow zone occurs much earlier than the conventional theory, at Reynolds number ranging from 800 to 2000. The Fanning friction factor is higher than predicted by the theory for smooth tube. Finally, the empirical correlations based on experimental data have been established for the design of similar micro heat exchangers