TURBINE REAR FRAME INTERFACE - THERMAL MODELLING IMPROVEMENT USING CFD BASED APPROACH

In the power generation world, Aero-derivative Gas Turbines plays an important role due to their inherent efficiency and Power to Weight advantage. There is a heavy competition among the manufacturers to capture the market with their best products. Baker Hughes has many products in this segment with a range of output levels. The Gas Turbine Rear Frame (TRF) is a structural member, which supports the Gas Turbine casings at the rear end and transfers the load to the base plate or ground. It also houses the last bearing on which the power turbine rotor is supported. Also, this component experiences hot gases on the mainstream side and relatively colder air on the cooling path. It has many non axi-symmetric features which makes the design of this component very challenging. This paper describes the approach used to improve the thermal prediction of the TRF, Rotor Aft Wheel Cavity and vent air cavity region, which is critical to understand the mechanical behavior of the component and assess the component life. Quasi-3D flow analysis is used to understand the flow structures in the cavities and simulated those flow structures in the 2D thermal models which improved the model prediction, and which is also validated with test data.