Numerical Study Of The Flow Uniformity Inside The High-Pressure Side Manifolds Of A Cooled Cooling Air Heat Exchanger

To maintain efficiency in advanced aero-engines, it is crucial to set high limits for the Operating Pressure Ratio (OPR) and Turbine Entry temperature (TET). This can be achieved using a Cooled Cooling Air (CCA) heat exchanger, which precools the compressed air with the bypass stream before the compressed air enters the turbine to cool the blades. The aim of the present study was to improve the aero-thermal performance of CCA heat exchangers by enhancing the uniformity of flow through its high-pressure (HP) side manifolds. The development of the new manifolds was constrained by their manufacturability, as well as the pressure drop across the heat exchanger. The inlet and outlet manifold geometries are parameterised, and Computational Fluid Dynamic (CFD) simulations are carried out for Maximum Take-Off (MTO) conditions. Shape changes were performed using the mesh morphing tool, which enabled the intermediate remeshing steps to be skipped. By means of regression analysis, it was possible to find inlet and exit manifolds with improved flow uniformity; the heat transfer, structural integrity, and weight of the baseline and new manifolds were then evaluated. The new manifolds were structurally sound, and showed an 18.8% improvement in uniformity, a 10.6% reduction in pressure drop, a 0.4% increase in heat transfer rate, and a 22.5% decrease in weight.