International Research Journal of Engineering and Technology (IRJET) Volume: 04 Issue: 02 | Feb -2017
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e-ISSN: 2395 -0056 p-ISSN: 2395-0072
A Review on “Investigation of Heat Transfer Enhancement of Flow over the dimples (triangular shape) using in Divergent Duct.” Sunil More1, Gaurav Khedkar 2, Prashant Patil 3, Abhay Yangal 4, Aniket Hajare 5 Keshav Kekan 6 1Assistant
Professor, Dept. of Mechanical Engineering, DY Patil college of Engineering, Pune, Maharashtra, India. Students, Dept. of Mechanical Engineering, DY Patil college of Engineering, Pune, Maharashtra, India. 3 Students, Dept. of Mechanical Engineering, DY Patil School of Engineering Academy, Pune, Maharashtra, India 2
---------------------------------------------------------------------***--------------------------------------------------------------------and improved mixing or flow swirl. These effects Abstract – The Effective fluid mixing is one of the generally result in an increase in pressure drop along requirements in food processing and chemical industry. The effect of divergent Duct is a good way to promote the flow with the increase in heat transfer. However, with mixing in Duct flow. When using divergent Duct then we get appropriate performance evaluation and concomitant flow difference means low pressure drop it is also called optimization, significant heat transfer improvement pressure recovery. By using Triangular shape as an extended relative to a smooth (untreated) heat transfer surface surface in the divergent Duct it can help us to increase the of the same nominal (base) heat transfer area can be heat transfer enhancement and Triangular surface present the achieved for a variety of applications. highest performance of the heat transfer enhancement. The Triangular surface act as extended surface (fin surface) and the main purpose of extended surface to increase the heat transfer rate. The advantages of the divergent Duct with internal Triangular surface are fluid mixing is more as compared to cylindrical pipe, pressure drop is less and boundary layer separation occurs as well as the heat transfer coefficient increases 40 to 50% as compare to plain divergent Duct .
C. Bi, G.H. Tang*, W.Q. Tao, et al.- [1] They concluded that The dimple surface presents the highest performance of the heat transfer enhancement, the performance of cylindrical groove surface is slightly lower than that of the dimple surface, and the low fin surface presents the lowest performance. The study on the independent geometry size effects of the dimple suggests that the deep dimple with large diameter can enhance heat transfer more easily . HONG Mengna**, DENG Xianhe, HUANG Kuo and LI Zhiwu, et al. - [2] They investigated that the pressure drop and compound heat transfer characteristics of converging-diverging tube with evenly spaced twisted tapes experimentally. In this paper they made comparison of experiment between smooth circular tube and converging diverging tube without carrying the twisted tapes.
Key Words: Heat transfer enhancement, Divergent Duct, Extended Surface (Triangular), Heat transfer rate, Heat transfer coefficient. INTRODUCTION
Heat transfer enhancement is the practice of modifying a heat transfer surface or the flow cross section to either increase the heat transfer coefficient between the surface and a fluid or the surface area so as to effectively sustain higher heat loads with a smaller temperature difference. Some practical examples of heat transfer enhancement. i.e fins, surface roughness, twisted tape inserts and coiled tube, which are generally referred to as passive technique. Heat transfer enhancement may also be achieved by surface or fluid vibration, electrostatic fields or mechanical stirrers. These latter methods are often referred to as active techniques because they required the application of external power. Although active techniques have received attention in the research literature their practical applications have been very limited. In this section therefore we focus on some specific example of passive techniques Increases in heat transfer due to surface treatment can be brought about by increased turbulence, increased surface area, © 2017, IRJET
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Kirti Chandra Sahu, Rama Govindarajan, et al. - [3] although the critical Reynolds number for linear instability of the laminar flow in a straight pipe is infinite. They show that the critical Reynolds number for linear instability of laminar flow is finite in case of divergent Duct and it approaches to infinity as the inverse of the divergence angle. A Dewan, P Mahanta, K Sumithra Raju and P Suresh Kumar, et al. - [4] In this paper it is shown that heat transfer can be enhanced by the use of passive techniques that is by modifying the geometrical shape of the pipe or duct and by insertion of twisted tapes, |
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