Steam compressor flow simulation close to the saturation line using non-ideal gas model

The heat supply for industrial production in the medium temperature range can be provided by green electricity to substitute fossil energy sources. Here the use of High-Temperature Heat-Pumps (HTHP) is a very promising technology to reduce significantly the power demand. The operation of the HTHP require a dedicated design of the turbomachinary used within. For the working medium low superheated steam a well-adapted non-ideal gas model is required for the 3DRANS simulations. In addition to the temperature dependence, a model adaptation is developed to include the pressure dependence of the gas properties within the CFD simulations. A polytropic state change in temperature and pressure is assumed and determined for the heat capacity along the estimated state change as function of this two gas properties. This polynomial function is developed and applied and only valid between the assumed inlet and outlet state of the compressor stage. A comparison is performed between the calorically and thermally perfect gas model close to a non-ideal gas model, for different operation points. The dependency of the assumed polytropic state change on the developed polynomial function will be shown. The method will be used in the centrifugal compressor design and will be a part of the process chain.