Thermal performance of a microchannel primary surface recuperator for portable microturbine generators: Design and experimental study

The recuperator with high compactness and power/weight ratio is a mandatory component of portable microturbine generators (PMTG) to achieve the required energy density and power density. In order to explore the application prospects of cross-wavy primary surface recuperators (CW-PSR), an annular microchannel CW-PSR with heat transfer matrix compactness up to 2428 m²/m³ was designed by an in-house one-dimensional steady-state heat transfer model and successfully manufactured. Furthermore, an experimental system consisting of gas and air flow paths was built to validate the developed model and investigate the thermal performance of the new CW-PSR. On this basis, heat transfer experiments were performed under steady-state by changing the mass flow rate and inlet temperature of the gas. The experimental results show a good agreement between modeled results and experimental data of the power/weight ratio and effectiveness within an error of ±2%. There exists a significant heat transfer non-uniformity in the radial direction of the CW-PSR, but it was found to have little impact on the design accuracy of overall thermal performance. Due to corrugated microchannels, the heat transfer performance of the developed CW-PSR has been enhanced by up to 113.3% compared with straight channels and the experimental power/weight ratio of the CW-PSR is in the range between 9.6 kW/kg and 16.1 kW/kg, which means the microchannel CW-PSR is a promising heat exchanger for the PMTG.