The flow part comparative analysis of a gas turbine engine intermediate casing with a starter generator integrated onto the rotor shaft

Abstract

The paper presents a flow part comparative analysis of a gas turbine engine intermediate casing with a starter-generator integrated onto the rotor shaft based on a more electric aircraft engine concept. This paper identified the need for design modifications and a gas-dynamic study of the intermediate casing of a two-stage compressor in a gas turbine engine. A description of the prototype engine’s intermediate casing design was provided, and several flow path geometry variants were constructed for a transition channel with an enlarged axial dimension. The design was also modified in terms of the circumferential arrangement of the racks, their shape, purpose, and quantity, compared to the intermediate casing of the prototype engine. Based on the design, computational models were developed and calculated in the gas-dynamic module of imported computational software at a specific engine operating mode. To construct the geometry and computational models, as well as to define the boundary conditions, we used methods developed by renowned experts, taking into account recommendations for changing the area, channel shape, inclination angles, turbulence models, mesh quality, and specifying conditions at the inlet and outlet of the transition channel. The velocity and pressure gradients in the longitudinal and transverse directions were obtained as the results. Based on the data obtained, the total pressure losses in each of the engine stage were calculated. Based on this research, areas for necessary modifications to the design of existing intermediate casings were identified when installing an integrated starter-generator with a central bevel drive in a gas turbine engine, as well as improvements to the channel flow parameters to ensure minimal total pressure losses at the gas generator inlet.