Mechanism of Heat Transfer Enhancement in Recuperators with Oblique Wavy Walls

摘要

Small-scale distributed energy systems with micro gas turbines are of great concern because of their high efficiency and low environmental impact. It is pointed out that one of the most important technical issues to improve the system efficiency is the effectiveness of recuperators. Recently, primary surface recuperators have been considered promising and employed in recuperated turbine systems. We report that the appropriate use of oblique wavy walls in counter flow recuperators can induce intense secondary flows and realize significant heat transfer enhancement at the cost of relatively small pressure loss. In the present study, the detailed mechanism of heat transfer enhancement is investigated in order to obtain a clue to optimal shape design of the passage geometry. We focus on the coupling effects of counter-flowing fluids on local heat transfer characteristics.