International OPEN ACCESS Journal Of Modern Engineering Research (IJMER) | IJMER | ISSN: 2249–6645 | www.ijmer.com | Vol. 4 | Iss.11| Nov. 2014 | 47| The Effect of insertion of different geometries on heat transfer performance in circular pipe- A review Amol P. Yadav 1 , Pranit M. Patil 2, Dr. P. A. Patil 3 1 P.G. Student, M.E. Heat Power, J.S.C.O.E, Hadapsar, Pune(M.S.) India 2 Assistant Professor, Department of Mechanical Engineering, G.I.T, Lavel, Khed (M.S.) India 3 Professor, Department of Mechanical Engineering, J.S.C.O.E, Hadapsar, Pune (M.S.) India I. INTRODUCTION When turbulent flow is considered, many techniques were investigated for augmentation of heat transfer rates inside circular tubes using wide range of inserts. The inserts studied included coil wire inserts, brush inserts, mesh inserts, strip inserts, twisted tape inserts etc. Heat exchangers have many industrial applications for example, heat recovery processes, air conditioning and refrigeration systems, chemical reactors, and food and dairy processes. For better performance and economic aspects of the equipment, the design of heat exchanger needs exact analysis of heat transfer rate and pressure drop. Garc et al. [1] investigated the laminar –transition–turbulent heat transfer enhancement and flow patterns in the tube with wire coil inserts. Hsieh et al. [2] experimentally studied the turbulent heat transfer and flow characteristics in a horizontal circular tube with strip-type inserts. Bhuiya et al. [3] studied the heat transfer performance and friction factor characteristics in a circular tube fitted with twisted wire brush inserts were investigated experimentally. Halit bas [4] Flow friction and heat transfer behavior in a twisted tape swirl generator inserted tube are investigated experimentally Bhuiya et al. [5] have done the experimental investigation on Nusselt number, friction factor and thermal performance factor in a circular tube equipped with perforated twisted tape inserts with four different porosities of Rp = 1.6, 4.5, 8.9 and 14.7%. M.M.K. Bhuiya [6] explored the effects of the double counter twisted tapes on heat transfer and fluid friction characteristics in a heat exchanger tube. The double counter twisted tapes used as counter-swirl flow generators in the test section. Pankaj N. Shrirao et.al [7] Experimental investigation of heat transfer and friction factor characteristics of horizontal circular pipe using internal threads of pitch 100mm, 120mm and 160mm with air as the working fluid. Bodius Salam et.al [8] have carried an experimental investigation for measuring tube-side heat transfer coefficient, friction factor, heat transfer enhancement efficiency of water for turbulent flow in a circular tube fitted with rectangular-cut twisted tape insert. In the above literature review, the numerous research articles were reported on heat transfer enhancement and pressure drop characteristics in tubes with various geometrical configurations of turbulence creator. Hence this study gives the overview of different techniques to enhance the heat transfer characteristics by producing turbulent flow in circular pipe with insertions of different types of inserts or geometries. 1. Twisted wire brush inserts 2. Twisted tape 3. Perforated twisted tapes 4. Double counter twisted tapes 5. Pipe with internal threads. Abstract: Under turbulent flow conditions, the increase in heat transfer rate is more significant than that under laminar flow conditions. The turbulent effects become a dominant factor over secondary flow at higher Reynolds number. The turbulent flow can be produced by inserting different geometries in the circular pipe. This study focuses on the various methods or geometries used to produce turbulent geometries and its effect on the heat transfer. The turbulent generators with different geometrical configurations have been used as one of the passive heat transfer enhancement techniques and are the most widely used in tubes in several heat transfer applications. Insertion of such geometries may lead to increase the friction factor and pressure drop which directly enhances the heat transfer characteristics. Keywords: Heat transfer characteristics, Turbulent flow, Reynolds number, Friction factor.