4 th National Conference on “Recent Developments in Mechanical Engineering” (RDME-2015), Jan. 29-30, 2015. COMPUTATIONAL HEAT TRANSFER ANALYSIS OF A COUNTER-FLOW HEAT EXCHANGER WITH FINS Suvanjan Bhattacharyya 1a , Anirban Roy 1b , Ayan Bhattacharyya 2 , Krishanu Dey 2 , Dipak Seth 3 1a 1b Mechanical Engineering Department, MCKV Institute of Engineering, Liluah, Howrah, West Bengal, India. 2 Mechanical Engineering Department, Academy of Technology, Hooghly, West Bengal. India. 3 Mechanical Engineering Department, Modern Institute of Engineering & Technology, Hooghly, West Bengal. India. 1a Email id – suvanjanr@gmail.com , Ph. No: +91 9477410056 1b Email id – anirban22roy@yahoo.co.in , Ph. No: +91 9163388923 Abstract — A numerical work has been conducted to examine laminar flow and heat transfer characteristics in a two-dimensional isothermal-fluxed circular-duct fitted horizontal with finned tapes. The computations are based on the finite volume method with the SIMPLE algorithm implemented. This paper reports the Computational Fluid Dynamics (CFD) modelling studies on heat transfer, friction factor and thermal performance of a counter-flow heat exchanger equipped with two types of tube insert including fins. The principle of heat transfer enhancement in the core flow of tube has been proposed to improve the temperature uniformity and heat transfer enhancement in the boundary flow of tube. The studied the temperature profile and velocity profile was obtained by the fins inserts with an inclined angle of 90°. The results have also revealed that the difference between the heat transfer rates obtained from two models with fins and without fins. The CFD predicted results were used to explain the observed results in terms of swirl intensity. Keywords— Heat exchanger, laminar flow, Reynolds number, Fin, CFD. I. INTRODUCTION A heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. Depending on the direction of flow occurring between the two media, heat exchangers are classified as Cross-flow, Parallel flow and Counter flow. The used of heat transfer enhancement has become widespread during the last so many years. The need of heat transfer enhancement is to reduce the size and cost of heat exchanger equipment, or increase the heat duty for a given size heat exchanger. This goal can be achieve in two ways active and passive enhancement. The active enhancement is less common because it requires addition of external power (e.g., an electromagnetic field) to cause a desired flow modification. In the passive enhancement, it consists of alteration to the heat transfer surface or incorporation of a device whose presence results in a flow field modification. The most popular enhancement is the fin. Fins are the extended surfaces which are used to enhance the rate of heat transfer dissipation from heated surfaces to air. Fins can be placed on plane surfaces, tubes, or other geometries. These surfaces have been used to increase heat transfer rate by adding additional surface area and encouraging mixing. When number of fins are used to enhance heat transfer under natural convection conditions the optimum geometry of fins (corresponding to a maximum rate of heat transfer) should be used, provided this is compatible with available space and financial limitations. The common fins used extensively to increase the rates of natural convection heat transfer from systems are rectangular fins because such fins are simple and cheap, to manufacture. Effective utilization of energy is one of the most important topics relating to limited fossil-fuel resources. While much energy is consumed in industrial processes, large amounts of waste heat at low temperatures are released. To recover waste heat effectively, improvement of heat exchangers is still needed even though they have been studied for a long time. There are two main methods to improve the overall heat exchange rate, the extension of the heat transfer area and increasing the heat transfer coefficient. In the former method,