Improvement of Two-Phase Flow Distribution in Compact Heat Exchangers by Using Ultrasound

In this communication we present a new active method to modify two-phase flow distribution in a heat exchanger, when it is in operation, by using ultrasound generators which can be activated when necessary. An experimental study has been carried out to validate the concept and to evaluate the effects of ultrasound on the flow distribution. An experimental test rig was built to measure the flow distribution in realistic manifold and parallel channel geometry. The test section is composed of a manifold feeding 10 channels with air-water mixture. In front of each channel a piezoelectric generator is placed to emit ultrasonic waves which can interact with liquid flows. Comparison was made between two-phase flows with and without ultrasound. It was demonstrated that, in most cases, uneven distribution was improved by using ultrasound.