Experimental and analytical investigation of a wavy fin recuperator for a micro gas turbine

•The performance of a wavy fin recuperator for a micro gas turbine is investigated.•A wavy fin recuperator was fabricated using laser-welding technique.•Experiments were conducted by varying hot air inlet temperature and mass flow rate.•An analytical model for the performance of the fabricated recuperator was proposed.•The proposed model can be implemented in design of a wavy fin recuperator. A recuperator is a mandatory component to achieve higher thermal efficiencies in micro gas turbines of less than 1 kW power. Owing to the lack of existing experimental data for high-temperatures, the pressure drop and heat transfer characteristics of a recuperator with wavy fins for a micro gas turbine were experimentally investigated. A wavy fin recuperator was fabricated using laser-welding technique. Experiments were conducted by varying the hot air stream inlet temperature and mass flow rate in the ranges of 250–500 °C and 1.5–4.0 g/s, respectively. Based on the experimental data, it was found that an increase in the fluid mean specific volume due to increase in the hot air stream inlet temperature resulted in larger pressure drops in the high-temperature range. On the other hand, the hot air stream inlet temperature variation scarcely affected the effectiveness of the fabricated wavy fin recuperator. In addition, an analytical model was proposed to predict the pressure drop and heat transfer characteristics of the wavy fin recuperator in the high-temperature range accurately. The effectiveness and total pressure drop results from the developed model were in close agreement with the measurement results, with relative errors less than 5.0% and 11.5%, respectively, regardless of the hot air stream inlet temperature and mass flow rate. Consequently, the proposed analytical model could be utilized as a design tool for recuperators with wavy fins for micro gas turbines.