Numerical experiment of flow in stages of inflow turbine with fractional blading of the rotor wheel

This paper discusses the flow features in the flow channel of an inflow low-consumption turbine with fractional blading of the rotor wheel. Such turbines belong to the design class of turbines of the so-called non-ventilation type. Due to the fact that the rotor blades are not contained on the entire pitch circle, while the nozzles in the nozzle diaphragm are placed around the entire circuit, this circumstance has a great influence on the flow regime in the nozzle diaphragm. First of all, the features of the nozzle diaphragm are that during the rotor wheel rotation the nozzles operate in the repetitive opening and closing mode, which is not observed in traditional type turbines. And such nozzles operating modes inevitably affect the regime of its flow and the kinetic energy loss. Thereby, a numerical experiment was conducted on the basis of the computational fluid dynamics software package with the need to determine the velocity field in the flow channel of the turbine in the conditions of periodic opening and closing of the extreme nozzles. This paper discusses uses the method of numerical simulation of three-dimensional flow using the of the computational fluid dynamics software package. The most suitable model is the non - stationary URANS model. In the course of the experiment, the following results were obtained: the Mach number in the flow channel of turbine on different modes of opening and closing the nozzle, the value of the speed coefficient of the nozzle diaphragm, and efficiency of turbine stages.