Configuration optimization of the tandem cooling-compression system for a novel precooled hypersonic airbreathing engine

The tandem cooling-compression (TCC) system possesses the potential to reduce the compression work and cooling fuel consumption in fuel indirect precooled engines. Selecting of system branch number and allocating the working fluid flow are key factors to achieve the optimum system performance. On account of this, configuration optimization for the system is carried out from the perspective of compression work minimization, with the optimum system design strategies are proposed, and the necessity of using the multi-segment precooler for efficient air precooling is clarified as well. The strategies reveal that only when the branch number and the total heat capacity ratio of the system are equal, the usual uniform flow distribution (UFD) strategy is meanwhile an optimum design choice. Based on the numerical models developed, the correctness of the proposed strategies is verified by Differential-Evolution algorithm, with the potential advantages of which are evaluated also at both the component and system levels. Compared with the UFD strategy, the results indicate that generally, the compression work and cooling fuel consumption can be further reduced, and also the operational range can be remarkably extended for the system designed with the proposed optimum strategies. Moreover, assisted with the multi-segment precooling scheme, the schemes can bring about even larger extent of fuel savings and air precooling depth, higher working fluid and air side pressure ratios, and ultimately considerable gains in engine performance.