Theoretical and experimental investigations on the radial and axial leakages within a rotary vane expander

Abstract

Rotary vane expander (RVE) is a perspective type of a volumetric expander for small series manufacturing due to its simple geometry and low manufacturing costs. Performance of this type of expander is usually worse in comparison with other volumetric expanders but it can be improved if we understand well the phenomena that occur during expansion within the vane expander.This work provides a theoretical and experimental analysis of the influence of various leakage pathways on the behaviour of a RVE. The RVE used in this work has been specifically modified for the possibility of adjusting the axial and radial clearances. Experimental data for the both clearances ranging from +0 to +0.5 mm were used to set up a 1D mathematical model, which, provides accuracy of parameter prediction within ±5%. Such model can be further used for optimization and design of RVE. In this paper, the model was used to analyse the effect of reducing manufacturing tolerances on the expander parameters.Analyses are performed for constant pressure difference (common in literature), as well as for the regime of constant heat input of the thermodynamic cycle (better reflects the conditions of the real expander operation and its effect to the entire cycle).