Effect of Longitudinal Pitch on Flow and Heat Transfer Characteristics of Working Fluid in Zigzag-type Channels and Development of New Correlations
Zigzag-type Printed Circuit Heat Exchanger(PCHE)with enhanced heat transfer ca-pability are one of the promising candidates for recuperator in supercritical carbon dioxide Brayton cycle.In this study,flow and heat transfer characteristics in zigzag-type PCHE is studied with different longitudinal pitch.Results show that the convective heat transfer performance of 30° zigzag-type PCHE varies less when the longitudinal pitch increases from 3 to 11 times of channel diameter,and decreases when the longitudinal pitch increases to 13 times of channel diameter;the convective heat transfer performance of 10° zigzag-type PCHE increases gradually when the longi-tudinal pitch increases from 3 to 13 times of channel diameter.These phenomena are mainly caused by the generation,convection,and dissipation of secondary flow at the corner of the zigzag channels.In this paper,a new kind of heat transfer correlation combined with longitudinal pitch is further proposed.
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