Experimental Study of Natural Circulation Based on Thermal Effect during Steady-State Condition

Natural circulation flow can passively transfer heat from the heat source to the heat sink without a pump mechanism. For this reason, this system can implement in many thermal engineering applications, such as nuclear power plants. Passive safety systems are one of the alternatives to reactor safety systems. The advantages of this system include simplicity and no need for external power. This study aims to determine the characteristics of temperature difference in the loop, flow velocity, and non-dimensional number correlation. The experimental method is the most relevant method to understand the passive cooling system; then, the results of this study will be compared with theoretical models and research results from previous researchers. The results showed that the higher the THTS, the more extensive the Reynolds number range. The same pattern also occurs in the Grashof number. In this experiment, the range values ​​for the Reynolds and Grashof numbers were 990 < Re < 2114 and 1.67 x 1011 < Gr < 1.22 x 1012.