Study on the Influence of Thermodynamic Effects on the Characteristics of Liquid Nitrogen Cavitating Flow around Hydrofoils

Abstract

Cryogenic cavitation exhibits complexities primarily represented by the coupled interactions of thermodynamic effects, vortices, and cavities during the cavitation process. To further investigate this coupling mechanism, this study employed the DDES turbulence model and Sauer–Schnerr cavitation model to perform unsteady numerical simulations of liquid nitrogen cavitation flow around the NACA0015 Hydrofoil. Numerical validation of the model utilized a symmetrical Hord hydrofoil. The results reveal that the upstream development of the recirculation flow under inverse pressure gradients is the fundamental cause of the detachment in the primary cavitation region. At a cavitation number of 0.616, thermodynamic effects noticeably suppress the formation of cavities and alter the range of adverse pressure gradients, consequently influencing the detachment behavior in the primary cavitation region.

Research on the Mechanism of Flow-Induced Vibration in the Cooling System of a Double Crystal Monochromator

“…The simulation covers a fluid time of 0 ∼ 3 s, with the first 2 s dedicated to excluding the initial liquid nitrogen inside the pipes and allowing the flow field to reach a stable state under actual operating conditions. Data sampling is performed only on the flow field at 3 s, with a sampling interval of 5 × 10 −4 s. During the calculation, the minimum time step is 2 × 10 −5 s, and the maximum time step is 5.5 × 10 −4 s. With the support of a 48-core 2.7 GHz high-performance workstation, the fluid calculation took 70 h. The relevant physical properties of liquid nitrogen and nitrogen gas are shown in Figure 5 [17,18]. initial liquid nitrogen inside the pipes and allowing the flow field to reach a stable state under actual operating conditions.…”