Numerical investigation of heat exchanger performances for a two engine aircraft in pusher configuration by an u-RANS code

摘要

This paper deals with the numerical analysis of the effect a heat exchanger has on the flow field in an oil cooling system for aerospace applications. To this end, an important upgrade of the UZEN in house CIRA Reynolds Averaged Navier-Stokes solver has been carried out to account for the pressure drop and heat rejection that usually are present in a heat exchanger. This upgrade is based on the addition of a source term in the momentum and energy equations of balance, respectively, whose values are updated during the simulation. The correspondent code modification needs a proper validation before any concrete application. At this aim, a two dimensional channel has been firstly studied in order to test the accuracy of the UZEN code. Then a three dimensional circular duct has been studied with a porous insert to validate the porous approach robustness. After this preliminary campaign of assessment, a new generation two engine aircraft has been studied with particular emphasis on its nacelle cooling system. Velocity and pressure are compared using different turbulence models with the well known Fluent ones. The more interesting parameter for such an investigation is the mass flow rate through the cooling ducts as computed by UZEN that show a good agreement with the Fluent one. (C) 2016 Elsevier Ltd. All rights reserved.