Design and testing of externally finned tube cavity receiver for Brayton cycle preheating purposes

Abstract

A novel dual pressurised tubular cavity air receiver for solarised Brayton cycle pre-heating had previously been proposed. The preheating receiver needs to obtain 800 °C pressurised air and 540 °C non-pressurised air for integration to be successful with a combined Brayton upstream and Rankine downstream cycle. Preliminary numerical investigations indicated that the non-pressurised air could not obtain the desired outlet temperatures. The ability of external fins to achieve this goal is investigated experimentally and compared to the theory to assess the ability of the theory to predict the thermal response of the two fluid streams. It was found that the theory employed accurate and that the receiver cannot obtain the desired non-pressurised temperatures at meaningful quantities in this design. The receiver demonstrated the ability to regulate the material thermal gradients which can potentially reduce cycling stress to some extent.