Multi-objective design optimization of topology and performance of branching networks of cooling passages

The objective of this study was to develop an automatic, self-sufficient, preliminary design algorithm for optimization of topologies of branching networks of internal cooling passages. Optimization with four levels of fractal branching channel networks was tested. The number of branches per level was optimized in order to minimize coolant mass flow rate, total pressure drop, and maximize total heat removed. The software package includes a random branches generator, a quasi 1-D thermo-fluid analysis code, and a multi-objective hybrid optimizer. The heat transfer/flow-field analysis software has been verified against a similar analysis code used by Pratt & Whitney Company. The hybrid multi-objective optimization code was verified against classical test cases involving multiple objectives. In this work the total number of Pareto-optimal designs was 100. After finding the Pareto optimized configurations, the user has to decide which optimized cooling network configuration is the best for the desired application. It was demonstrated that this can be accomplished by utilizing Pareto-optimal solutions to create a curve representing pumping power vs. total heat removed and by observing which designs provide favorable break-even energy transfer.