电浆体激励下水翼间隙空化特性数值研究

Numerical Research on Influence of Plasma Actuation on Cavitation Characteristics of Hydrofoil Gap

摘要:

为探究水翼间隙空化的主动控制方法，采用数值模拟方法，耦合LES模型、Schnerr-Sauer空化模型及电浆体唯象学模型，在激励电压15kV、水翼攻角8°、来流速度10m/s条件下，分析了电浆体激励对NACA66(MOD)水翼间隙空化特性的影响。结果表明：未激励条件下，小间隙时，剧烈的片空化和剪切流抑制了尖端泄漏涡空泡的发展，使其只蔓延至水翼侧壁中下游，随着间隙的增大，片空化和剪切流减弱，对尖端泄漏涡的抑制作用降低，尖端泄漏涡空化发展得更远；电浆体激励使小间隙水翼的片空化和云空化强度减弱，但剧烈和不稳定的涡系结构使尖端泄漏涡空化未得到有效抑制；电浆体激励通过提高大间隙水翼的侧壁压力，破坏空化发展条件，抑制了分离涡的发展和诱导涡的产生，增强了尖端泄漏涡的稳定性，实现对水翼间隙空化的显著抑制，一定程度改善了水翼的水动力特性。

Abstract:

Aiming to investigate the active control methods for cavitation in the gap between hydrofoils, numerical simulations were conducted by using a coupled LES model, Schnerr-Sauer cavitation model, and phenomenological plasma model. Under the conditions of an actuation voltage of 15kV, a hydrofoil angle of attack of 8°, and an incoming flow velocity of 10m/s, the effects of plasma actuation on the gap cavitation characteristics of an NACA66(MOD) hydrofoil were analyzed. The results showed that without plasma actuation, in the case of small gaps, intense sheet cavitation and shear flow suppressed the development of tip leakage vortex cavitation, limiting its propagation to the mid and lower part of the hydrofoil sidewall. As the gap increased, sheet cavitation and shear flow were weakened, reducing the suppression effect on the tip leakage vortex, allowing the cavitation to develop further. Plasma actuation weakened sheet cavitation and cloud cavitation for small-gap hydrofoils, but the intense and unstable vortex structures hindered effective suppression of tip leakage vortex cavitation. For large-gap hydrofoils, plasma actuation increased the pressure on hydrofoil sidewall, disrupting the conditions for cavitation development, suppressing the development of separation vortices and the generation of induced vortices, and enhancing the stability of the tip leakage vortex, and achieving significant suppression of gap cavitation. This led to significant suppression of cavitation in the hydrofoil gap and improves, to some extent, the hydrodynamic performance of the hydrofoil.