开缝帽罩水滴撞击特性研究

Study on Water Droplet Impingement Characteristics of Slit Cap

针对吹风比对帽罩缝后区域水滴撞击特性的影响,通过计算提出水滴受气膜影响效应的相关判据。通过实验发现气膜对水滴具有吹袭作用,随着吹风比的增大,水滴撞击系数逐渐减小,吹风比为0.24、0.53和1时的最大水滴撞击系数与吹风比为0时的结果相比分别下降了6.73%、10.95%和17.11%;针对帽罩外形,计算发现在吹风比、来流速度和水滴直径3个变量任意组合下(v<70m/s),水滴受气膜影响存在有限吹除、吹向后部和完全吹除3种效应,拟合出左右临界水滴直径判据和St判据。实验结果表明:该研究有助于加深对帽罩热气防冰的理解,对开缝帽罩防冰结构设计具有一定的参考价值。

In view of the influence of blowing ratio on the impingement characteristics of water droplets in the region behind the hood gap,the relevant criteria for the influence of air film on water droplets are proposed through calculation.It is found that the air film has a blowing effect on water droplets.The water droplet impingement coefficient decreases with the increase of the blowing ratio.The maximum water droplet impingement coefficients at the blowing ratios of 0.24,0.53and 1 decrease by 6.73%,10.95% and 17.11%,respectively,compared with the results at the blowing ratio of 0.According to the shape of the cap,it is found that there are 3 kinds of effects on the water droplet under the influence of the air film,namely,limited blowing,backward blowing and complete blowing,under the arbitrary combination of the 3 variables of blowing ratio,incoming flow velocity and water droplet diameter (V70 m/s),and the left and right critical water droplet diameter criteria and St criterion are fitted.The experimental results show that the study is helpful to deepen the understanding of the hot air anti-icing of the hood,and has a certain reference value for the anti-icing structure design of the slotted hood.