Optimization Design In Three-fluid Heat Exchanger For Airborne System

With the development of science, technology, material, and the increasingly severe energyproblems, multi-fluid plate-fin exchanger came out at the right moment and got great developmentwith the characteristics of miniature, light-weight, compact and efficient. It has been widely used inlots of field at present.This paper devotes to enhance the comprehensive performance of multi-fluid plate-fin heatexchangers from three aspects, that is, the optimization of passage arrangement, the calculation ofheat transfer, and the optimization of structure. First of all, use Monte-Carlo Method to create thepassage arrangement, optimize the passage arrangement with the minimum mean-square deviation ofpassage accumulative total heat load as optimization objective, then check out the rationality of theoptimum principle by the numerical modeling method, discuss the applicability on variable conditions.Secondly, according to the idea of comprehensive method, comprehend the fluid that absorb or sendout heat respectively, making it to be a equivalent two-fluid heat exchanger, then derive the formula ofheat transfer of multi-fluid heat exchanger refers to the two-fluid one, in the same way, check out theaccuracy by the numerical modeling method and obtain the key factors that influence the accuracy.Thirdly, create a fin database according to the experimental result made by predecessors, usedimensionless method to obtain the objective function of the optimal structure, let the objectivefunction minimum, then a optimal arrangement, minimum volume, minimum pressure drop, andoptimal comprehensive performance multi-fluid heat exchanger can be designed. Finally, apply themulti-fluid plate-fin heat exchanger to the environment control system, design a glycol-fuel-rush airplate-fin heat exchanger and check it by the numerical modeling method, give the structure diagramand temperature graph. The result shows that, the method of optimization design of multi-fluid heatexchanger that this paper offered is effective.