Numerical Study on the Thermal Performance of a Novel Impinging Type Solar Receiver for Solar Dish-Brayton System

Sammanfattning: An impinging type solar receiver has been designed for potential applications in a future Brayton Solar Dish System. The EuroDish system is employed as the collector, and an externally fired micro gas turbine (EFMGT) has been chosen as the power conversion unit. In order to reduce the risks caused by the quartz glass window, which is widely used in traditional air receiver designs, a cylinder cavity absorber without a quartz window has been adopted. Additionally, an impinging design has been chosen as the heat exchange system due to its high heat transfer coefficient compared to other single-phase heat exchange mechanisms. This thesis work introduces the design of an solar air receiver without a glass window, which features jet impingement to maximize the heat transfer rate. A detailed study of the thermal performance of the designed solar receiver has been conducted using numerical tools from the ANSYS FLUENT package. Concerning receiver performance, an overall thermal efficiency of 72.9% is attained and an output air temperature of 1100 K can be achieved, according to the numerical results. The total thermal power output is 38.05 kW, enough to satisfy the input requirements of the targeted micro gas turbine. A preliminary design layout is presented and potential optimization approaches for future enhancement of the receiver are proposed, regarding local thermal stress and pressure loss reduction. This thesis project also introduces a ray-thermal coupled numerical design method, which combines ray tracing techniques (using FRED®), with thermal performance analysis (using ANSYS Workbench).