The possibility of flow mal-distribution is recognized by equipment designers and often requires special design techniques available only to those with the in-depth experience in this area. Existing solutions to flow distribution difficulties are often expensive or ‘one-of-a-kind’ designs tailored to a limited flow range. A comprehensive study of capabilities of a robust, low cost, and low maintenance technique, such as electrohydrodynamics (EHD), is warranted.

The main objective of this project was to experimentally establish the validity of the EHD technique as mal-distribution control method for correcting the sub-optimal distribution that commonly occurs in commercially available evaporators. Specifically, the flow distribution control utilizing the EHD conduction pumping mechanism has been experimentally and theoretically investigated in this project at single-phase liquid and two-phase liquid/vapor (in the presence and absence of heat transfer). Flow distribution control under operating conditions of direct relevance to HVAC & R applications has been investigated. The results indicate that the EHD conduction pumping can be used to effectively correct/control single-phase and two-phase flow mal-distributions. This is achieved with a negligible input electric power to operate the EHD conduction pump.