悬臂方向对TLV空化抑制效果的影响及其机理

该文综合利用实验及数值模拟方法细致研究了悬臂式沟槽叶顶间隙泄漏涡(tip-leakage vortex, TLV)空化抑制器的悬臂凸出方向对抑制TLV空化效果的影响，并对其原因进行了深入讨论。研究表明:相比于原始水翼叶顶处的TLV空化，无论悬臂凸出方向指向水翼的吸力面还是压力面，悬臂式沟槽TLV空化抑制器在各个间隙大小下均能产生显著的抑制效果。相对而言，当所采用的悬臂凸出方向为压力面时，该装置对TLV空化的抑制效果更为显著，且可更有效地抑制TLV空化体积脉动。测量结果表明:悬臂凸出方向对水翼升、阻力系数影响均很小。数值结果则进一步表明:当采用悬臂凸出方向为指向压力面时，悬臂式沟槽TLV空化抑制器能更好地抑制流体从压力面流向吸力面，干扰TLV的生长，进而可以更加有效地抑制TLV空化的发展。

THE INFLUENCE OF THE DIRECTION OF OVERHANGING GROOVES ON THE SUPPRESSION OF TLV CAVITATION AND ITS MECHANISMS

The influence of the direction of overhanging grooves on the suppression of tip-leakage vortex (TLV) cavitation is investigated experimentally and numerically, and the mechanisms behind it are discussed in detail. The results indicate that both the overhanging grooves (OHGs) with the overhanging at the suction and pressure sides show a significant suppression on TLV cavitation for a large range of gap sizes. Compared with the OHGs with overhanging at the suction side, a better suppression effect can be obtained by the OHGs with overhanging at the pressure side. Moreover, the OHGs with overhanging at the pressure side can provide a more satisfying suppression on the fluctuation of the cavity volume of TLV cavity. The experimental measurements indicate that the influence of the direction of overhanging grooves on the lift and drag coefficients of the hydrofoil is quite slight. The numerical results further indicate that the OHGs with overhanging at the pressure side can impede the flow from the pressure side to the suction side more effectively and disturb the development of TLV, which is helpful for the suppression of TLV cavitation.