CONVECTIVE HEAT TRANSFER FROM FINS-ON-TUBES HEAT EXCHANGERS IN AN OSCILLATORY FLOW

Thermoacoustic effect occurs when an acoustically induced oscillatory flow interacts with internal solid structures such as thermoacoustic stacks/regenerators, whereby the conversion between acoustic power and thermal energy takes place. Heat exchangers are often employed to enable heat input/removal between the working medium around the thermoacoustic stacks/regenerators and the surroundings. In this work, the non-dimensional parameters controlling the fluid flow and heat transfer around a plain-fin heat exchanger are first identified. The thermal performance of three fin-on-tube type of heat exchangers is then studied experimentally in an acoustically induced oscillatory flow. The mean heat transfer coefficient is evaluated via the LMTD (logarithmic mean temperature difference) approach. The effects of the controlling non-dimensional numbers on the non-dimensional heat transfer coefficient (Nusselt number) are presented and discussed, together with the measurement uncertainty.