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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

A NEW REDUCTION TECHNIQUE FOR NON LINEAR THERMAL MODELS WITH CONDUCTIVE AND RADIATIVE COUPLINGS

Get access (open in a dialog) DOI: 10.1615/IHTC10.3950
pages 385-390

Resumo

We present a novel technique for the reduction of non-linear thermal models described by algebraic systems such as : A [T] + B [T4] = [U ] where A, B, U are constant matrices or vector, [T] is the vector of temperatures at the model nodes, [T4] is the vector of the fourth power of temperatures and U the vector of sources or prescribed temperatures. An elimination procedure is used to build a reduced system, approximately equivalent to the original one, that remains non-linear and accounts for the sources of the eliminated nodes. After completion of the elimination process, the description of the reduced model as a thermal network is retrieved by an appropriate conditioning of the matrices of the reduced algebraic system : this ensures an easy implementation of this reduction method in any standard thermal network analyzer. Results are presented mainly in the case of an heat exchanger system involving simultaneously conduction, convection and radiation. A 67% reduction rate has been achieved in this case with an error not above IK when the results of the reduced and full models are compared..