Experimental investigation of pressure drop of water flow in a double vertical coils and shell heat exchanger induced by 28 kHz ultrasound

Abstract This research experimentally investigated the pressure drop characteristics induced by 28 kHz ultrasound in a double vertical coils and shell heat exchanger, typically used in 3 – 10 tons water chiller. Also, the water inlet was positioning as 3 configurations, including 1: configuration 1 is the original model from a commercial type (2 ports to the coil center), 2: configuration 2 is the modified model to make a swirl in the heat exchanger (4 ports on 4 side walls), and 3: configuration 3 is the modified model that vertically injects water to the coil (4 ports on a top wall). The results showed that the pressure drop increased in accordance with the flow rate from 0.25 to 0.75 l/s. The second inlet configuration was found to be a promising setup due to its lowest occurring flow friction. Especially in the operation under ultrasonic waves, this configuration provided a lower pressure drop of approximately 20%. Therefore, the maximum reduction of pressure drop was at 86.6% from the original configuration at the lowest flow rate. These results lead to the better design of the heat exchanger and the consequence of higher efficiency water chiller in the future.