Optimising the locations of thermally sensitive equipment in an aircraft crown compartment

A Design of Experiments (DoE) analysis was undertaken to generate a list of configurations for CFD numerical simulation of an aircraft crown compartment. Fitted regression models were built to predict the convective heat transfer coefficients of thermally sensitive dissipating elements located inside this compartment. These are namely the SEPDC and the Route G. Currently they are positioned close to the fuselage and it is of interest to optimise the heat transfer for reliability and performance purposes. Their locations and the external fuselage surface temperature were selected as input variables for the DoE. The models fit the CFD data with R2R2 values ranging from 0.878 to 0.978, and predict that the optimum locations in terms of heat transfer are when the elements are positioned as close to the crown floor as possible (SySy and Ry→min. limitsRy→min. limits), where they come in direct contact with the air flow from the cabin ventilation system, and when they are positioned close to the centreline (SxSx and Rx→CLRx→CL).The methodology employed allows aircraft thermal designers to optimise equipment placement in confined areas of an aircraft during the design phase. The determined models should be incorporated into global aircraft numerical models to improve accuracy and reduce model size and computational time.