Degradation of the performance of microchannel heat exchangers due to flow maldistribution

The effect of flow maldistribution on the performance of microchannel parallel plate heat exchangers is investigated using an established single blow numerical model and cyclic steady-state regenerator experiments. It is found that as the variation of the individual channel thickness in a particular stack (heat exchanger) increases the actual performance of the heat exchanger decreases significantly, deviating from the expected nominal performance. We show that this is due to both the varying fluid flow velocities in each individual channel and the thermal cross talk between the channels transverse to the direction of the flow.

► Performance degradation of microchannel heat exchangers when the flow channels are inhomogeneous.
► Effective heat transfer coefficient is shown to deviate significantly from the ideal.
► Thermal cross talk in microchannel heat exchanger is investigated.