Theoretical modelling and experimental investigation of the modified revolving vane expander (M-RVE)

•The theoretical model of a modified revolving vane expander was developed.•The model was validated with the experimental results.•An improved test rig was developed, and experimental studies carried out.•Up to 55% volumetric efficiency and 11% isentropic efficiency was achieved. Expansion devices are a key component that affects the performance of the Organic Rankine Cycles (ORCs), and its improvement has been identified as one of the most important parts of future studies in ORCs. A theoretical model of a modified revolving vane expander was developed in this study. The model was to investigate the inherent physical processes and the effect of losses on the mechanism. The developed model was validated with the experimental results. The experiments were carried out using an improved experimental rig with direct coupling of the dynamometer and expander to eliminate any externally exerted misalignments. The results of the theoretical validation showed that the torque is generally slightly underpredicted, but the trends are very closely predicted. Moreover, a little underprediction was observed in the theoretical study of mass flow rate but still within the uncertainty of the experiments. The experimental results showed the prototype could generate up to almost 0.8 N.m and rotated up to 1700 rpm at a suction pressure of 3 bar(g). Moreover, the prototype demonstrated up to 55% volumetric efficiency and 11% isentropic efficiency at 3 bar(g) of the suction pressure.