International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 04 | Apr -2017
p-ISSN: 2395-0072
www.irjet.net
"Experimental investigation of heat transfer enhancement by u-shaped Turbulator" Pawar Shubham(1) ,Pailwan Vidyadhar (2), Kothawale Shridhar(3) , Vaibhav Sonavane (4),Akshay Londhe(5) 1,2,3,4UG
Scholar, FTC, COER, Sangola professor, FTC, COER, Sangola ---------------------------------------------------------------------***--------------------------------------------------------------------(5)Assistant
Abstract - An experimental investigation was carried out to
find the optimum U shape turbulator array pattern on flat surface. The researchers have documented theories related to U shape turbulator array pattern (i.e. staggered array,inline array etc). Protrusions like U shape turbulator are mounted on internal flow passage to augment the heat transfer. This project work is related to investigation of the forced convection heat transfer over U shape turbulator array. The objective of work is to find heat transfer rate and frictional characteristics from test surface and results are compared with flat surface. The U shape turbulator array pattern is in Vangled shape ( 120°) with pitch is 40mm & 50mm , side by side with pitch is 25 mm & 30 mm, staggered arrangement with 30mm & 40mm.The Nusselt number, friction factor and thermal performance index was measured, U shape turbultor form are rectangle in shape with 45mm in width and 15mm in height, test plate is having dimensions of 600 x 100 x 6mm. The Reynolds number based on hydraulic diameter was varied from 17509.19 to 39153.5. Key Words: Protrusion, heat transfer enhancement, turbulator array, Nusselt number, friction factor, thermal performance index. 1. INTRODUCTION The heat transfer rate in flow passage is increased by three techniques such as passive, active techniques and compound technique. Passive techniques are more preferable because of its simplicity in design and fabrication also the cost for fabrication is low in comparison with active and compound techniques.It includes the surface roughening or geometrical modifications in the flow channel which alters flow distribution and promotes more heat transfer. Another technique used is active technique, these techniques are complex to design and implement because it requires external input to disturb the flow. It includes mechanical aids, surface vibration, fluid vibration, electrostatic fields, and injection, suction and jet impingement. A number of experimental investigations have done turbulator arrays and turbulator shapes. The flow disturbance is maximum for side by side arrangement of © 2017, IRJET
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turbulators due to higher vortex generation than inline array . The oval shape turbulators are more efficient than spherical turbulator, with the peak end at upstream and round end at downstream produces more mixing of fluid which promotes the heat transfer rate. analytically analysed convective heat transfer in turbulised flow past a turbulatord surface. A parametric study is performed with k-ε turbulence model to determine the effects of Reynolds number, turbulator depth and Nusselt number on heat transfer enhancement, and have computed heat transfer coefficients in a channel with one side turbulatord surface. The Reynolds number based on the channel hydraulic diameter was varied from 200000 to 360000.They showed that more heat transfer was occurred downstream of the turbulators due to flow reattachment. Due to the flow recirculation on the upstream side in the turbulator, the heat transfer coefficient was very low. As the Reynolds number increased, the overall heat transfer coefficient was also increased. This experiment includes study of heat transfer rate from angular, side by side ,staggered turbulator array plates of angle 1200 & 30mm and 40 mm pitch.25mm&30mm pitch The Reynolds number ranges from 17509.19 to 39153.5. The heat transfer rate is given by the Nusselt number ratio i.e. ratio of practical Nusselt number and theoretical Nusselt number. The friction factor is calculated with help pressure drop across test section and compared with theoretical friction factor which is given by Dittus-Boelter equation. The obtained results are compared with flat plate results. 2. EXPERIMENTAL INVESTIGATIONS Experimental Set Up An experimental set up has been designed to obtain the heat transfer rate in rectangular duct for turbulatord surface plate. Figure 1 shows the schematic diagram of experimental setup. This apparatus is open air flow duct that consist of blower (1) supplies air with Reynolds number ranges from 12000 to 30000, flow control valve (2) which is provided to adjust and control the flow,orifice meter (3) to measure the Reynolds number, entrance section (4), flow straightener (5) to convert the flow through circular pipe into
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