Peculiarities of computer modeling of the working process in small gas turbine engines

Abstract

The article describes a thermo-gas-dynamic model of small gas turbine engines. The model takes into account the influence of the engine size on the efficiency of work processes in the crucial components. Gas turbine engines are classified according to their size depending on the value of the gas generator mass flow rate corrected by the compressor exit parameters. An important feature of the working process in small gas turbine engines is that hydraulic losses in the flow section increase with the decrease in the engines size due to the increase of the boundary layer relative thickness. The efficiency of the compressor and turbine also decrease because of the increase in relative radial clearances. These factors are taken into account in computer modeling by making allowances for the initial values of compressor efficiency, fuel combustion efficiency, the total pressure loss coefficient and turbine efficiency. The suggested approaches were used to improve computer models of gas turbine engines. It is shown that reducing the engine size results in considerable decrease of the work process optimal parameters and specific parameters. Taking into account the influence of the engine size on the efficiency of its components widens the range of its applicability and improves the adequacy. Thus, the models provide a more adequate solution for the optimization of working process parameters and can be used for conceptual designing of small gas turbine engines.