Investigation on performance enhancement of micro-channel separated heat pipe in data center: A coupled heat-mass-flow characterization approach

As data center continues to expand in scale and complexity, the demand for efficient heat dissipation solutions becomes increasingly critical. The utilization of micro-channel separated heat pipe is prevalent in data center cooling due to their low energy consumption and efficient cooling. This study aims to investigate the effects of different refrigerant flow rates, different inclination angles and different inlet vapor phase fractions on the heat transfer and flow characteristics of micro-channel separated heat pipe evaporator. Firstly, a simulation model of the heat pipe evaporator was established considering the heat-mass-flow coupling characteristics, and the fins were modeled and simplified without neglecting the enhanced heat transfer. Then, the experimental data are used to verify the established simulation model, and the error is within the acceptable range. Finally, scheme design and performance optimization research are conducted. Research on the inlet flow rate of R134a shows that when the inlet flow rate is 0.005 m/s, the outlet is superheated vapor. The presence of an inclination angle (0 degrees-20 degrees) in the evaporator not only significantly reduces the pressure difference between the outlet and the inlet (more than 30 %), but also improves the heat transfer coefficient and the refrigerant velocity magnitude. In addition, increasing the inlet vapor volume fraction promotes vapor bubble nucleation and reduces the pressure drop, but leads to the presence of outlet overheating. The findings of this study contribute valuable insights for advancing thermal management strategies in data center environments.