Volume No. 12 Issue No.: 3 Page No.: 312-322 January-March 2018

 

EXPERIMENTAL STUDY ON HEAT TRANSFER AUGME-NTATION IN HORIZONTAL TUBE USING COILED WIRE INSERTS

 

Emani Madhu Sruthi *, Nayak Abhik, Chowdhuri Achin Kumar and Mandal Bijan Kumar

Department of Mechanical Engineering, IIEST Shibpur, Howrah, West Bengal (INDIA)

 

Received on : September 20, 2017

 

ABSTRACT

 

The use of various enhancement techniques to augment convective heat transfer coefficient inside tubes has been investigated for many years. The high cost of energy and material has resulted in an increased research for producing more efficient heat exchange equipment. In this present work, the effects of coiled wire inserts with different cross-section, on the heat transfer enhancement and friction factor characteristics of air flow through a horizontal pipe have been experimentally studied. The experiment was conducted in a forced convection set-up using coiled wire inserts of different cross-section, pitch and helix angle. The experiment has been carried out under uniform heat flux condition for the turbulent flow, with Reynolds number (Re) = 6400 to 15200 and Prandtl number (Pr) = 0.7. The use of circular and square coiled wire inserts resulted in considerable increase in heat transfer as compared to a smooth tube at constant pumping power especially, at lower Reynolds number. The heat transfer augmentation ratio is observed to range from 1.6 to 2.9. Also, the overall enhancement efficiency using coiled wires with square cross-section is found to be around 10% more than that of coiled wires with circular cross-section for same thickness and Reynolds number.

 

Keywords : Heat transfer coefficient, Augmentation, Coiled wire, Overall enhancement efficiency

 

 

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