Steady State Performance of a Single Phase Natural Circulation Loop With End Heat Exchangers

2008 ◽  
Vol 130 (8) ◽  
Author(s):  
N. M. Rao ◽  
B. Maiti ◽  
P. K. Das
Keyword(s):  
Steady State ◽  
Heat Exchangers ◽  
Iterative Procedure ◽  
Single Phase ◽  
Natural Circulation ◽  
Circulation Loop ◽  
Circulation Rate ◽  
Natural Circulation Loop ◽  
Analytical Expressions ◽  
Steady State Performance

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.

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 ◽  
...  
Keyword(s):  
Steady State ◽  
Ambient Temperature ◽  
Single Phase ◽  
Numerical Models ◽  
Natural Circulation ◽  
Circulation Loop ◽  
Periodic Oscillations ◽  
Heater Power ◽  
Natural Circulation Loop ◽  
Moderate Power

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.

Effect of heater and condenser orientations on fluid flow behaviour in a two-phase natural circulation loop

2021 ◽  
pp. 095440892110158
Author(s):  
S Venkata Sai Sudheer ◽  
K Kiran Kumar ◽  
Karthik Balasubramanian
Keyword(s):  
Steady State ◽  
Natural Circulation ◽  
Circulation Loop ◽  
Systems Of Equations ◽  
Two Phase ◽  
Natural Circulation Loop ◽  
Vapour Quality ◽  
Position And Orientation ◽  
Developed Pressure ◽  
Steady State Performance

A Numerical investigation on the influence of heater and condenser orientation and its location on steady state performance of a Two Phase Natural Circulation Loop (TPNCL) is presented. In the present study, four possible orientations are considered in TPNCL namely, Vertical Heater and Vertical Condenser (VHVC), Vertical Heater and Horizontal Condenser (VHHC), Horizontal Heater and Horizontal Condenser (HHHC) and Horizontal Heater and Vertical Condenser (HHVC). An in house MATLAB code is developed to solve the systems of equations. Homogeneous equilibrium model (HEM) is used in two phase regions. It is observed that steady state mass flow rate of the loop is significantly influenced by the developed pressure gradient in the riser and downcomer sections, as well as available vapour quality in the riser section. Moreover, it is also noticed that condenser position and orientation significantly effects the thermo-hydraulic characteristic of loop compared with heater orientation.

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