NUMERICAL ANALYSIS OF THE EXPANSION PROCESS IN A TWO-STAGE AXIAL TURBINE OPERATING WITH MDM SILOXANE

The problem of decreasing of fossil fuel consumption and energy efficiency is one of today’s major conceptions in the field of energy economics. Waste heat recovery is one of the promising solutions for this problem. One of the ways to increase efficiency of the waste heat recovery process is using siloxanes as working fluids for organic Rankine cycles (ORC). SPbPU scientists have analyzed peculiarities of the steady-state expansion process in the two-stage MDM siloxane turbine. The turbine is based on the principle of a classic velocity stage. First stage of the turbine was designed using the SPbPU high pitch-chord ratio supersonic design. The airfoils of the second stage are subsonic. A pressure ratio of the turbine is 37.2. Progressive steps of the initial temperature, pressure ratio and rotational velocity were used to obtain convergence of the solution process. The main factors, leading to the efficiency decreasing, were established and described. The efficiency and power output of the investigated turbine stage were estimated as 67 – 68% and 544 kW respectively.