Computational study of cavitation around modified hydrofoils including thermodynamic effect

Cavitation around hydrofoils is a complex multiphase flow problem, which causes damage to turbomachines, such as pumps and/or hydro reaction turbines. Literature findings suggest that the addition of a small rectangular obstacle on the top surface of a hydrofoil can be a simple and effective strategy in reducing the cavitation damage. However, it remains uncertain whether such a technique would still work at elevated temperatures where the absorption and release of latent heat (i.e., thermodynamic effect) may significantly affect the vaporization and condensation processes. This computational study examines the combined influence of surface modification and thermodynamic effect on cavitation behavior of water flowing over a two-dimensional NACA0015 hydrofoil. The modified Zwart–Gerber–Belamri cavitation model is adopted in the temperature range of T = 298.15–343.15 K (25–70 °C). Multiple cavitation numbers are considered, namely, σ = 1.5, 0.8, and 0.5 reminiscing sheet, cloud, and supercavitation regimes, respectively. The results suggest that the placement of an obstacle may reduce the cavitation extent over hydrofoil surface for the cases with σ = 0.8 and 0.5 across different temperature regimes. However, when σ = 1.5, the obstacle's presence leads to the formation of additional vapor cavities downstream of the hydrofoil. The findings of this research can pave the way for resilient design of hot water pumps and/or hydro reaction turbine systems.