縦横比の異なる矩形オリフィスからのキャビテーション噴流の可視化と流量特性

抄録

This study focused on the characteristics of a cavitating jet issuing from a small rectangular orifice with different aspect ratios. The orifice size is similar to the control port in a water hydraulic spool valve. The authors conducted the flow visualization to capture the overall and cross-sectional jet images. The maximum Reynolds number based on the equivalent diameter is approximately 1.3×10⁵. The results show that cavitation bubbles generate in the jet shear layer and just downstream the jet exit. The shape of the cavitation region varies with the streamwise position except for the two-dimensional orifice having an aspect ratio (AR) of 38.3. In the square orifice, the cavitation region rotates at 45 degrees from the jet exit like an axis switching. The cavitation region in the jet of AR=6.76 deforms from the rectangular shape. On the other hand, under the large aspect ratio condition, the shape of the cavitation region is maintained relatively downstream.