Experimental and Numerical Investigation of a Single-Phase Square Natural Circulation Loop

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Ritabrata Saha ◽  
Swarnendu Sen ◽  
Saikat Mookherjee ◽  
Koushik Ghosh ◽  
Achintya Mukhopadhyay ◽  
...  

Experimental and numerical analyses are carried out for a natural circulation loop (NCL) under low and moderate heater power. The effect of ambient temperature variation on the loop thermal behavior has been taken into account in present study. The effect of liquid inertia has a role in the initial transience, as revealed by the numerical and experimental observations. The steady-state results from the present analyses are validated with the reported dimensionless results for NCL. The experimental steady-state results are in fair agreement with the developed lumped numerical models. At moderate power, the numerical and experimental results indicate periodic oscillations.

2008 ◽  
Vol 130 (8) ◽  
Author(s):  
N. M. Rao ◽  
B. Maiti ◽  
P. K. Das

In the present investigation, the steady state performance of a rectangular single phase natural circulation loop (NCL) with end heat exchangers is studied. One-dimensional governing equations are considered in developing the mathematical model. Analytical expressions are derived for the circulation rate and temperature profile. However, the individual performance parameters are to be computed iteratively as the equations are strongly coupled. A suitable iterative procedure is given to evaluate the important loop parameters such as steady state flow rate, and riser and downcomer temperatures. Few special cases are discussed where analytical expressions for circulation rate and temperature distribution can be obtained directly without any iterative procedure. It is also shown that both the hot and cold end heat exchangers should have equal conductance (UA) for maximization of circulation rate. This feature of NCL is identical with heat power cycle and can be explained in light of equipartition principle.


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