A numerical investigation on head losses and flow qualities for a large cavitation tunnel without impeller

Abstract

In this study, a numerical investigation of the flow quality and total head loss of a large cavitation tunnel is conducted. Excluding the impeller, the entire tunnel is modeled, and calculations are conducted for the test section's maximum speed of 15 m/s. The numerical study showed that an edge chamfer eliminates the pressure drop in the test section, resulting in a constant cavitation number downstream, and that a diverging top diffuser, as opposed to a flat top, induces upward flow at the exit of the test section. Also, the effectiveness of the flow straightener and honeycomb in reducing turbulence has been validated. In the test section, the turbulence intensity is 0.10% and the uniformity is 0.20%. The 2nd corner has the highest head loss due to the shaft. Due to the relatively high speed, significant head losses are observed in the test section, diffuser, and first corner.