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To predict the temperature distribution of an alternator in an automobile engine, a computational fluid dynamics (CFD) analysis was applied to a complicated alternator geometry. This analysis revealed the complicated flow patterns and temperature distributions in the alternator. Moreover, an algorithm for predicting the frequency of the noise generated by the alternator’s cooling fan was devised. Then, the pitch angle was optimized by commercial software in order to improve the tone quality, therefore, unpleasant noise of the fan could be reduced by making the noise level for each order equal. It is concluded that these computational tools (i.e., the algorithm and software optimization) can effectively improve the tone quality of the fan noise and, when combined with CFD analysis, they can significantly reduce both the time and cost of developing an alternator.

In order to develop a high-performance turbocharger turbine, compressible turbulent flow analysis is applied to the complicated flow around the nozzle vanes and the spacers. The flow analysis indicates that a combination of a curved nozzle vane and a round spacer causes a low-velocity region at the inner side of the nozzle vane even when the turbine efficiency is highest. As a result of the loss analysis, a teardrop-shaped spacer, which suppresses the low-velocity region and flow separation, is developed, and shown to improve the turbine efficiency. The easiness of the nozzle vane control is also important as well as the high efficiency. The fluid force on the nozzle vane depends on the flow pattern; therefore, the torque about the pivot of the nozzle vane is also numerically calculated.