An Experimental Investigation of Two Phase Natural Circulation Loop (NCL) with End Heat Exchangers

The steady state behaviour of two-phase natural circulation loop with heat exchangers at the hot and cold ends is studied experimentally. A vertical rectangular and uniform cross section Natural Circulation Loop (NCL) with end heat exchangers is designed and fabricated. Steam is used as hot fluid and tap water as cold fluid. The experimentation is carried out for various hot fluid flow rates. Four flow patterns are identified viz. Small bubbly flow, big bubbles flow, stream of small bubbles, churn flow. It is concluded that Circulation rate of the loop fluid rises with hot fluid flow rate. However heavy fluctuations in the flow rate of coupling fluid are observed the reasons of which are explored.