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The rotor airfoil design has the characteristics of multi-point, multi-objective and strong constraints. Based on the evolutionary multi-objective optimization method, Kriging method and B-splines airfoil shape parameterization method, combined with the concept of Pareto optimality and constraint-handling mechanism, a rotor airfoil design and optimization system is built. In Kriging model the sample points are selected by using the uniform design, and the accuracy of the model is adjusted by the Expected Improvement criterion during the optimization procedure. The airfoil is parameterized by using the B-spline definition which has good flexibility. The airfoil performance is evaluated using Navier-Stokes code, and the transition model was added into the code to improve the computation accuracy of drag. The rotor airfoil design is studied using the design system, and the optimized airfoil was tested in a tunnel. The results show that the aerodynamic performance of optimized airfoil has been improved significantly, and the feasibility if the optimization method is validated. [ABSTRACT FROM AUTHOR]

Taking the total average friction work of crankshaft bearings and the mass of crankshaft as objectives, a multi-objective integrated optimization is conducted on the crankshaft bearings of a four-cylinder engine by using particle swarm optimization (PSO) algorithm with exponent decreasing inertia weight strategy. The results are compared with original engine and the results of single objective optimization, and it is shown that after multi-objective integrated optimization, the total average friction work of crankshaft bearings decreases by 26.2 % and the mass of crankshaft reduces by 5.3% compared with original engine, and it has also a slight improvement over the results of single-objective optimization. [ABSTRACT FROM AUTHOR]