Experimental Analysis of Fluid Flow and Heat Transfer in a Finned Tube Thermosyphon System

摘要

Flat Plate Collectors (FPC) working on natural circulation or closed loop thermosyphon systems are widely used for heating water. The useful heat absorbed by the liquid medium is estimated by calculating the difference between the energy absorbed by the collector and the losses from it. The useful heat content in the liquid can be calculated directly, if the mass flow rate is known. In the present work the mass flow rate under different heat flux conditions is estimated under steady state condition. Experiments are conducted on a single fin tube assembly made of standard 12.5 mm copper rube of about 2 m length to which two copper fins are attached 180° apart to act as an absorber surface. It is observed that the flow of water lies in the mixed convection regime at low heat flux and transforms to developing region under higher heat flux conditions. A regression equation is developed to estimate the mass flow rate of water under different heat flux conditions applicable in the solar insolation range.