螺旋桨空化初生的判定和空化斗的数值分析

摘要：
为了实现空化多相流模拟在螺旋桨空化初生和空化斗预报中的应用，采用改进Sauer空化模型和修正剪切应力输运(SST)湍流模型，对NSRDC4381桨的叶背和叶面片空化初生、梢涡空化初生和空化斗底线特征进行了模拟、校验和分析，提出了“当σ>σi时，叶梢截面压力系数分布不再改变”的空化初生判定准则，并分析了其适用范围. 同时，将空化斗由传统的三区细分为五区，以更准确地描述不同工况点的桨叶空化状态. 结果表明，在设计和非设计进速系数下，预报桨叶叶背和叶面不同叶截面的初生空化数均与实验值吻合较好；模拟梢涡空化初生再现了局部梢涡空化和导边梢涡空化同时存在的现象，证明了分别用叶背07 R截面和叶面04 R截面的片空化初生曲线来表征叶背和叶面可视梢涡空化初生的合理性. 空化初生判定准则适用于空化斗底线上方的叶背和叶面片空化区. 将空化斗底线下方区域进一步细分为叶背03 R至叶梢的片空化区以及叶背与叶面同时片空化区，以更好地在工程中应用空化斗来描述桨叶空化形态和求取空化航态的航速.

Determination of Propeller Cavitation Initial Inception and Numerical Analysis of the Inception Bucket

To apply the cavitation multiphase simulation for propeller cavitation inception and inception bucket prediction,the improved Sauer cavitation model and modified shear stress transport turbulence model were used to predict the NSRDC 4381 propeller’s back and face sheet cavitation inception,tip vortex cavitation inception and inception bucket bottom line characteristics.A rule to determine the cavitation inception was presented printed as ’when σ>σi,the pressure coefficient of the tip blade section is unchangeable’ and its application region on the bucket was limited also.Based on it,the inception bucket was partitioned more nicely from traditional three regions to five at last so to depict the blade cavitation stage under different conditions more precisely.The results show that,under design and non-design conditions,the predicted inception cavitation indexes of the back and face’s blade section all agree well with the experiment.The simulated tip vortex cavitation inception represents the phenomenon of local tip vortex and leading edge tip vortex combination,and verifies the reasonableness of using the sheet cavitation inception curves of 0.7 R section on the back and 0.4 R section on the face to stand for the back and face’s visual tip vortex inception respectively.The determination rule is valid for both back and face sheet cavitation region up the bottom line on the bucket.The region under the bottom line on the bucket can be partitioned as back sheet cavitation lying 0.3 R to tip on the blade surface and back and face sheet cavitation existing simultaneously in addition,so to sever the engineering better for using the five regions to depict the propeller cavitation and calculate the cavitation ship speed.