Convective Heat Transfer Analysis in a Circular Tube with Different Types of Internal Threads of Constant Pitch
Pankaj N. Shrirao1, Rajeshkumar U.Sambhe2, Pradip R.Bodade3
1Pankaj N. Shrirao, Department of Mechanical Engineering, Jawaharlal Darda Institute of Engineering & Technology, Yavatmal, India.
2Dr. Rajeshkumar U. Sambhe, Department of Mechanical Engineering, Jawaharlal Darda Institute of Engineering & Technology, Yavatmal, India.
3Pradip R. Bodade, Department of Mechanical Engineering, Jawaharlal Darda Institute of Engineering & Technology, Yavatmal, India.
Manuscript received on January 22, 2013. | Revised Manuscript received on February 12, 2013. | Manuscript published on February 28, 2013. | PP: 335-340 | Volume-2 Issue-3, February 2013. | Retrieval Number: C1124022313/2013©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: This work presents an experimental study on the mean Nusselt number, friction factor and thermal enhancement factor characteristics in a circular tube with different types of internal threads of 120 mm pitch under uniform wall heat flux boundary conditions. In the experiments, measured data are taken at Reynolds number in range of 7,000 to 14,000 with air as the test fluid. The experiments were conducted on circular tube with three different types of internal threads viz. acme, buttress and knuckle threads of constant pitch. The heat transfer and friction factor data obtained is compared with the data obtained from a plain circular tube under similar geometric and flow conditions. The variations of heat transfer and pressure loss in the form of Nusselt number (Nu) and friction factor (f) respectively is determined and depicted graphically. It is observed that at all Reynolds number, the Nusselt number and thermal performance increases for a circular tube with buttress threads as compared with a circular tube with acme and knuckle threads. These are because of increase in strength and intensity of vortices ejected from the buttress threads. Subsequently an empirical correlation is also formulated to match with experimental results with ± 8% and ± 9%, variation respectively for Nusselt number and friction factor.
Keywords: Internal threads, Enhancement, heat transfer and turbulent flow.