Numerical investigation on the impact of injection rates on cooling performance in a rotor-stator cavity with liquid nitrogen spraying

This paper presents a numerical investigation of the steady-state cooling performance in a rotor-stator cavity with liquid nitrogen spraying under dimensionless mass flow rate ( C ω ) ranging from 1760 to 7040. The disc temperatures are set at 100°C, 200°C, and 300°C, respectively. For all the cases, the rotational speed of the rotor is consistently set at 1000 revolutions per minute. A validated numerical method based on the Volume of Fluid (VOF) technique for simulating two-phase flows, incorporating evaporation-condensation effects, is established and verified using transient test data. The study investigated the influence of injection rates and heating temperatures on heat transfer coefficient distributions. It was found that the peak heat transfer can reach up to 4015.1 W/(m 2 ·K). Higher injection rates lead to an increase in the spray cone angle, aiding in enhancing temperature uniformity. A comparison of liquid nitrogen discharge coefficients under superheated and subcooled conditions highlights the significant impact of flash evaporation within the nozzle on the spray cone angle and flow rate stability. In instances where liquid nitrogen is highly subcooled, the discharge coefficient closely resembles that of water. Furthermore, a new correlation for the local Nusselt number is established as a function of [Formula: see text] [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] using an exponential relationship, with a relative error not exceeding ±10%.