CFD study of heat transfer and pressure drop for oscillating flow in helical rectangular channel heat exchanger

The heat transfer and pressure drop under oscillatory condition in helical rectangular channel heat exchangers are numerically investigated by using uniform design method. The correlations of three models with different ratios of height to width are obtained. The results show that the channel with the largest ratio of length to width has a larger heat transfer rate and a lower friction factor. Then, the field synergy principle is used to analyze heat transfer enhancement of helical rectangular channel heat exchanger. Besides, the Performance Evaluation Criteria (PEC) method has been used to compare the thermal-hydraulic performances of helical rectangular channel heat exchanger with helically coiled tube heat exchanger. The results show that the helical rectangular channel heat exchanger has a better performance operating at high frequency and high velocity. So it is more suitable for the Stirling type machines. Finally, a helical rectangular channel heat exchanger was experimentally used in our thermal-compressor system to verify the present numerical result.