Abstract

Experimental investigation has been carried out to study the effect of thermal enhancement factor, heat transfer and friction factor in a smooth tube and two different test tube having internal threads of pitch (p=1.78mm, p=3.57mm), with water as a working fluid. For experimentation purpose Reynolds number were varied in the range of 4000 to 9000. The copper tube (OD=38mm, ID=28mm, t=5mm) was subjected to constant and uniform heat flux. The experimental data obtained from test tube having different surface texture i.e. by internal threading of different pitches (p=1.78mm, p=3.57mm) were compared with smooth circular tube. The effect of different surface texture of inside tube i.e. by threading with varying pitch on thermal enhancement factor, heat transfer and friction factor were presented. The heat transfer rate for tubes having internal threads was found to be much higher than smooth circular tube for a given Reynolds number. So simply by changing the internal surface texture the performance of circular tube improved.

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