MULTI-SOURCE THERMAL MODEL FOR ELECTRICAL HARNESS DESIGN

The challenges of improving wiring harness design are safety, ecology, weight and cost. To achieve this, a better prediction of the temperature in the wiring harnesses is necessary. In terms, this involves considering a lot of compact thermal sources with an uncontrolled layout. Up to now, the main methods dedicated to resolution are based on finite elements given that temperature's evolution according to several thermal sources, Joule effect, without controlled wire layout is complicated to evaluate. This paper deals with an alternative and faster method. An analytic equation : Infinite Line Source (ILS), is used to create a nodal network. This method coming from geothermal heat exchangers relies on a fully-connected node network which is called here full-graph method. It will be shown that, for compact heat sources, this method can be improved with a reduced model. A reduced model is a pruned node network: only the wires corresponding to the adjoining wires are selected. The bundle is a complex system which has a variable environment and an uncontrolled wire layout. The adaptation required by the models requires many assumptions. This case study focuses on a 10 wire configuration with the following assumptions: stationary state, identical wires, axial heat fluxes and neglected heat convection. Comparative studies between the two nodal methods and a Finite Volumes Method (FVM) are also presented and discussed. From a physical point of view, the results are more interesting. Further investigations, depending on the different parameters, should lead us to make more realistic nodal methods.