Simulation and experiment research on wide ranging working process of scroll expander driven by compressed air

Scroll expanders are widely used in the small energy recovery systems to recover mechanical energy from compressed air. A simulation model has been developed in this paper by taking the suction loss, leakage loss, heat transfer loss, and discharge loss into consideration. This simulation model is validated by comparison with the experimental results. The deviation of the actual working process from the ideal process is attributed to the leakage and heat transfer. The mass in the chamber decreases with the increase of rotation angle at the beginning of expansion first and then increases. The power output increases with a rise in rotating speed and the simulated power agrees well with the measurement at the rotating speed of 1740–2340 rpm. The delivery and the volumetric efficiency increase with rotating speed and the maximum volumetric efficiency is 0.69 with the clearance of 0.04 mm. The volumetric efficiency could be improved by reducing the radial and axial clearances between scrolls. Both the suction and discharge pressure loss increase with the rotating speed.