Numerical research on the flow and heat transfer characteristics in the immersion jet cooling for servers

Abstract

Immersion cooling and jet impingement liquid cooling, as two of the significant emerging direct contact liquid cooling methods, have promising prospects for development and application. The two cooling methods are combined and numerical simulation is applied to study the heat transfer performance of the immersion jet-cooled server. The orthogonal method is employed to determine the optimal structural parameters of the immersion jet, and the flow and heat transfer characteristics under different inlet and outlet layouts are investigated. The study shows that the optimal heat dissipation effect and moderate pressure are achieved when the ratio of jet distance (L) to jet pipe diameter (D) is 1.2, and the ratio of jet hole spacing to jet orifice diameter is 11.1. When the inlet and outlet of the cabinet are arranged in a Z-shaped layout, the pressure on the server surface is reduced by 17.1 %–31.6 % compared to a U-shaped layout. When the inlet and outlet of the cabinet are arranged in a Z-shaped manner with the inlet at the bottom and the outlet at the top, the highest heat transfer coefficient is over 24000 W/(m2 · K), which is approximately 1.5 times higher than that of other layouts. Through dimensional analysis, a quadratic function was selected to fit the relationship between heat transfer coefficient h, server pressure P and jet ratio (D/L), opening area A; In addition, the criterion relationship of Nu = f (Re, Eu) is fitted according to the simulation data, which provides a theoretical basis for energy saving and consumption reduction in data centers.

Keywords

• Immersion jet cooling
• Orthogonal analysis
• Flow and heat transfer characteristics
• Temperature uniformity
• Dimensional analysis
• Dimensionless criterion relation