NUMERICAL INVESTIGATION OF A TRANSONIC DENSE GAS FLOW OVER AN IDEALIZED BLADE VANE CONFIGURATION

Abstract

A joint numerical and experimental investigation of an idealized blade vane configuration, representative of an ORC turbine, is undertaken using Novec649 as the working fluid. First laminar-turbulent transition over the blade is studied by means of large-eddy simulation (LES). The geometry of the leading edge is modified to avoid an incipient separation. Afterwards, RANS simulations are carried out for both air and Novec649. The dense gas flow achieves a lower pressure ratio and exit Mach number compared to air, while shock waves generated at the blade leading edge are weaker. However, the dense gas induces a lower base pressure resulting in higher losses. Qualitative and quantitative comparisons with experiments and with a wall-modeled LES are also planned.