International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 07 | July -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 980 Optimization of Thermal Performance of Double Pipe Heat Exchanger using Mechanical Turbulators Jashanjot Singh Cheema 1 , Sandeep Salodkar 2 , Gurjeet Singh 3 , S K Soni 4 1 M.E. Scholar, Department of Mechanical engineering, PEC University of Technology, Chandigarh 23 Assistant Professor, Department of Mechanical engineering, PEC University of Technology, Chandigarh 4 Associate Professor, Department of Mechanical engineering, PEC University of Technology, Chandigarh ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - This research work is focused on Optimization of Double Pipe Counter Flow Heat Exchanger. The Coiled Mechanical Turbulators are inserted in pipe of Heat exchanger and experiments are performed by varying Spacing between Turbulators, Mass flow rates of Hot and cold waters. Values of Overall Heat Transfer coefficient and pressure drop are obtained. Taguchi Method was used to optimize Overall Heat Transfer coefficient & Pressure drop individually and later Grey Relation Analysis (GRA) has been employed for simultaneous optimization of multi-response characteristics i.e. Overall Heat Transfer coefficient and Pressure Drop. Research provided the optimum values for individually of Overall Heat Transfer coefficient and Pressure drop and also optimum values for both simultaneously. For the Overall Heat Transfer Coefficient, it was observed that optimal combination of process parameters are mc is 1500lph, mh is 2000lph, pitch is 2cm and optimum value for Overall Heat Transfer coefficient is 7486.57 w/m 2 k and pressure drop at these parameters is 3014.78N/m 2 .For the Pressure Drop it was observed that Optimal combination of process parameters are mc is 1500lph, mh is 1500lph, pitch is 10cm and optimum value for pressure drop is 1785.17 N/m 2 and Overall Heat Transfer coefficient at these parameters is 4682.17 w/m 2 k. Using GRA, optimization of the multi response has been converted into single response called grey relation grade and the optimal combination of the process parameters for multiple performance optimization has been found to be mc is 1500lph, mh is 1700lph, pitch is 6cm and the optimal value for Overall Heat Transfer coefficient s 5803.994 w/m 2 k and Pressure drop is 2408.8N/m 2 . Key Words: Heat Enhancement, Mechanical Turbulators, Optimization, Taguchi, Grey Analysis Abbreviations and Symbols Abbreviation Description SN Signal to Noise lph Litre Per Hour HP Horse Power KW Kilowatt mc Mass flow Rate of cold water mh Mass flow rate of Hot water Symbol Description ▲P Pressure Drop U Overall Heat Transfer coefficient Q Heat m Meter cm Centimetre N SN Normalized SN ratio ξ Grey Relation Coefficient ἠ Grey Relation Grade 1. INTRODUCTION 1.1 Heat Transfer Enhancement Techniques The augmentation of heat transfer is defined as the process to increase the heat transfer rate in heat exchanger. This process also helps to redesign the heat exchanger by reducing the size of heat exchanger but also high initial investment. Broadly the devices which are used to enhance the heat transfer rate in pipe of heat exchanger are called turbulators. And these turbulators are divided into two categories Active and Passive. Active Techniques for Heat Transfer Enhancement-Active techniques of heat transfer enhancement are those which require external power ex. surface vibration, fluid vibration, injection, suction, and electric or acoustic fields. Passive Techniques for the Heat Transfer Enhancement-The passive techniques of heat transfer enhancement are those which does not require any external power for there working. These can be applied by installing the turbulence generators or turbulators, e.g. the insertion of twisted stripes