小型軸流ファンの効率改善に関する研究 : 第2報,翼端漏れ渦の静圧と静圧効率への影響(流体工学,流体機械)

概要

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In our previous study, a high efficiency small axial-flow fan was designed by using the design tool based on computational fluid dynamics (CFD) and numerical optimization. The optimized fan efficiency was increased by 17% compared to the initial fan. In this study, a detailed CFD simulation of the initial and optimized fans was carried out to investigate the dominant factors for designing a high efficiency fan. The detailed CFD simulation was conducted to capture the tip leakage vortex. Breakdown of the tip leakage vortex occurred in the initial fan, and the tip leakage vortex interacted with an adjacent blade. Therefore, a reverse flow region was expanded around the vortex core in the initial fan. On the contrary, the breakdown of the tip leakage vortex did not occur in the optimized fan. Therefore, a reverse flow region was not expanded around the vortex core in the optimized fan. The breakdown of the tip leakage vortex significantly affected static pressure and fan efficiency because it caused an increase in total pressure loss. As a result, suppressing the breakdown of the tip leakage vortex was found to improve static pressure and fan efficiency. Increasing the outlet angle at tip, increasing solidity at tip, and decreasing the number of blades were effective in suppressing the breakdown of the tip leakage vortex.
2009-09-25