Visual Experimental Study on Two Phase Flow Patterns of the Evaporative Cooling System

The flow pattern is of great significance for calculating boiling heat transfer and two phase flow pressure drop, and there is no uniform flow pattern diagram for the evaporative cooling system. This paper has carried out experimental research on the flow pattern in the liquid box of the surface-mounted evaporative cooling system and establish a mathematical prediction model of flow pattern transition. The experimental results show that the flow patterns are mainly bubble flow, churn flow, and misty flow in the liquid box of the surface-mounted evaporative cooling system under different thermal loads. By comparing observed flow patterns with existing flow pattern diagrams, it can be found that the existing flow pattern diagrams are not suitable for the flow pattern division of surface-mounted evaporative cooling system. A new flow pattern diagram is proposed based on the change of interfacial area concentration in the liquid box. The prediction results of the new flow pattern diagram are in good agreement with the experimental data, which provides valuable insights into the flow pattern and paves the way for further boiling heat transfer calculation of surface-mounted evaporative cooling system.