5.1. Orthogonal experiments and MEA-BPNNThe levels of experimental factors are shown in Table 6. Commonlyused three-level orthogonal tables include L9(q4), L18(q7),and L27(q13). Based on the selection principle for orthogonal tables[38], L18(q7) is adopted in this paper. Each experiment in theorthogonal table is simulated by Fluent and the results correspondingto qV are given in Table 7.