Abstract
This thesis focuses on the aerothermal analysis of the intermediate pressure compressor (IPC) drum of a jet engine and the associated internal fluid flow. Emphasis is given to the CFD modelling of the drum internal flow, associated heat transfer and coupled FEM/CFD aerothermal analysis of the drum for a flight cycle. At the engine operating conditions two main types of flow occur in the internal cavities of the IPC drum; radial inflow and axial throughflow. Evaluation of two turbulence models, the κ-e model and the Reynolds stress model (RSM), for the prediction of these flows, is one of the aims of the present study. Experiments of radial inflow in a rotating cavity by Firouzian et al. (1985) and Farthing (1989) showed a high degree of swirl velocity in the core region of the cavity and this rotating core is found to influence the wall torque and heat transfer to a great extent in such cavity flows. Various test cases are considered to evaluate the turbulence models for the prediction of radial inflow in narrow and wide stationary cavities, rotating cavities with different radius ratios a/b, gap ratios s/b and shroud geometry. The rotating cavity test cases covered a range of rotational Reynolds number (Re φ,b) from 1.7 x 105 to 1.2 x 106, mass flow parameter (Cω) from 1,300 to 10,100 and inlet swirl fractions from 0 to 1. 0. The RSM performed reasonably well in predicting the flow and heat transfer for all the tested cases. Axial throughflow experiments by Farthing et al. (1991) showed vortex breakdown of the central jet and a strong correlation of jet breakdown modes to the jet Rossby number Ro. Unsteady Reynolds-averaged Navier-Stokes (URANS) models and large eddy simulations (LES) subgrid scale models are assessed for the prediction of such axial throughflow by carrying out a full 360 degree time dependent simulations. The RSM and LES predicted the flow field and breakdown frequencies reasonably well. Based on the above rotating cavity validation studies and the standalone CFD studies of the IPC drum internal flows, the 2D κ-e model and 3D RSM are selected for the coupled FEM/CFD simulations. Predictions from the coupled FEM/CFD simulations are compared with the engine test measurements. These simulations showed significantly improved predictions of the metal temperatures inside the IPC drum at various locations. This work will be a valuable addition to the ongoing efforts to carry out the whole engine computational model at the Surrey UTC and Rolls-Royce plc.