Characterization of Oscillating Flow Heat Exchanger of the Thermoacoustic Engine

In this paper, core engine components of a 10 kW free piston Stirling generator with a linear heat pipe coupled is taken as an example to illustrate the basic heat transfer and resistance characteristics of the oscillating flow heat exchanger of a thermoacoustic engine. By equating a 3D model, the Sage ID model and CFD 2D model arc adopted respectively to characterize the distribution of basic state parameters and time-averaged energy of the alternating flow heat transfer unit under rated operating conditions. The results show that the Sage ID model is similar to the CFD 2D model in terms of the heat transfer distribution characteristics and the total amount of heat transfer calculated. The Sage ID model can better capture the transient and time-averaged characteristics in the heat exchanger. However, the sudden cross-sectional losses at the heat ex-changer interface calculated with the Sage ID model deviate greatly from those calculated by the CFD 2D model. As a result, a local drag correction coefficient is proposed based on the resistance values calculated with the CFD 2D model, and according to the effective pressure drop and effective velocity at the abrupt cross-section. After the correction coefficient is used in the Sage model, the drag characteristics obtained using this model basically match those acquired using the CFD 2D model. The resultant heat exchanger characteristics and analysis method can be used to guide the research and engineering design of other thermoacoustic heat exchangers, exhibiting their general applicability. © 2023 Xi'an Jiaotong University. All rights reserved.