Raynal Glises

Transient thermal computation of a PEM fuel cell by a nodal modeling

In this paper, the authors propose a thermal modeling of a fuel cell. It has been validated on a 150 W power PEMFC. The thermal modeling uses a network of 172 nodes. It takes into account conduction and convection heat fluxes but also mass transfers due to electrochemical reaction. This thermal model is reduced to a global model describing electrical behavior and takes into account temperature regulation of the water cooling system. Matlab-Simulink software has been used. Dirichlet boundary conditions are obtained thanks to an SW infrared camera.

Thermal modelling for electrical machines fed with low voltage

Permanent magnet electrical motors are more and more currently used in car manufacture. A very constraining utilization reduces their life duration. Authors of this paper propose a new way to define reliability criterions of these low power machines. Most of internal fragility locations are winding insulations, ball bearings so that the system collector and brushes. Nowadays, statistical determination methods of the reliability criterions are very costly. For this reason, authors propose a new method consisting in the development of thermal models for different surrounding temperatures. It will also take into account degradation laws of constituting materials as functions of reached temperatures and life duration. This article will detail the initial validation of the thermal models for surrounding temperatures of 25 and 85^oC.

Heat Modeling of the Catenary’s Contact Wire During the Electrical Power Supply of Trains in Station

The overheating problem of the railroad catenary at the contact with the pantograph when the train is stopped and electrically fed is responsible of many incidents. This paper describes an experimental study and a numerical model of a catenary/pantograph system used during the preconditioning of the train. Several incidents of wire breakage have highlighted the importance of the catenary/pantograph heating problem, in those incidents the contact wire had melted and broke itself. The experimental setups consists of estimating the contact’s thermal resistance and area in order to calculate which part of the interface heat flux go throught the catenary’s contact wire and which part go throught the pantograph’s collector strip. The numerical model is based on several phenomena as heat conduction into the wires, heat exchange with ambiance through convection, Joule effects and heat flux from the interface.Copyright