Volume 6 Issue 2 (2018) 122-129 ISSN 2347 - 3258 International Journal of Advance Research and Innovation 122 IJARI Heat Transfer Enhancement Of Radiators Using Various Approaches: Review Zakariya Ahmed * , Akanksha Mishra Department of Mechanical Engineering, Sharda University, G-Noida (UP), India Abstract This paper reviews heat transfer enhancement of radiators using different approaches. It has been found that different method of heat transfer augmentation has been employed in different radiator design. These methods ranging from fin design modification, increasing core depth of radiator, change of tubes type, increasing surface area of radiator core, change of fin material, change of flow arrangement and changing the different types of fluid and mixture concentration. The performance of a radiator depends on its thermal and hydrodynamic performance. Certain parameters are of importance to the radiator performance such as; convective heat transfer co-efficient, pressure drop, inlet and outlet coolant temperature, air and coolant mass flow-rates, fin type, fin dimension and material. The various approaches are considered, depending on the application requirement and utilizing range. Radiator design modification such as increase in number of fins and tubes, material substitution have their limitations with certain negative consequences like added cost and weight with low efficient thermal performance compare to utilization of Nano-fluid approach. The engine life and its performance depend on coolant temperature. The application of nano-fluid in automobile radiator as coolant greatly affects the performance of the engine which in turn enhances its life span and fuel consumption. This paper attempts to review literature related to various heat transfer enhancement methods in vehicle radiator with different design, and compares the most effective approach amongst the methods taking into consideration cost, weight and thermal efficiency. 1. Introduction Radiators are heat exchangers used to transfer thermal energy (heat) from coolant liquid medium to atmosphere for the purpose of cooling the engine. The radiator comprises of core, top and bottom tank. Core is formed with two sets of passageway, one set of tube and also fins. Liquid coolant is flow inside the tubes at the moment’s air gets flow through the fins. The heat at that moment in the engine is absorbing by the liquid coolant and conveying in to the radiator, heat transfer takes place between solid body fins and atmospheric air [1]. High amount of heat is generated while engine is running; this can cause the temperature to a very high level, and capable of damaging the engine components. Therefore, for the components of the engine to be secure, the engine should run at minimum required temperature, which is called engine working temperature. The cooling system of an engine, maintains the working temperature by removing excess heat while engine is running. Additives such as coolant, a mixture of water and antifreeze flows through the engine cooling system and take in the excess heat and dissipate it though radiator [1]. Generally radiators are used to cool down automotive engine; radiator failure can result to so many problems like cylinder and piston deformation etc. which can further result to engine failure. A properly function radiator help cooling system work properly which in turn enhance engine performance. Various types of radiators are now in use, in which air is employed as heat transfer medium because of its availability [2]. Automobile engine performance can be enhanced by effective removal of heat transfer from the engine. There are different techniques for heat transfer improvement employed; these are by increasing surface area, efficient geometry, increase of coolant flow rate, enhancing the properties of heat transfer fluid, change of fins material etc. Automobile radiators with flat tubes are characterized with enhanced heat transfer. Flat tube radiators are widely used due their higher heat transfer area and lower air side pressure drop compared to round tube radiators of the same capacity [3]. 2 The Improved Heat Exchanger The performance of HE is defined by its thermal performance, by improvement in convective heat transfer co-efficient, h, and by its hydraulic performance, amount of power consumed in pumping fluid. 2.1 Method of Heat Transfer Techniques There are various techniques on how to enhance heat transfer in *Corresponding Author, E-mail-address: 2016006428.ahmed@pg.sharda.ac.in All rights reserved: http://www.ijari.org Fig.1: Schematic of Radiator [3] thermal devices; the following are active approach, passive approach and compound approach of improving heat transfer. The acceptable method is the one that does not require or consume large amount of pumping power with larger heat transfer enhancement. 2.2 Active Method Active heat transfer enhancement approaches require external power input, it is done with help of mechanical devices, such as fans, blowers. 2.3 Passive Method The passive method of heat transfer improvement does not require any external power input. This approach of heat transfer enhancement can be achieved by increasing the effective surface area and resistance time of the heat transfer fluid. 2.4 Compound method When both active technique and passive technique are used simultaneously for increasing heat transfer of any devices, which is greater than by using any one method at a time, then this term is known as the compound method. Uses both external power sources and geometry design changes 3 Heat Transfer Enhancements in Automotive Radiator There are various approaches to re-designed more compact (effective) radiators. These methods that can be employed to optimized heat transfer performance of new radiator design are by considering and changing the fin design, increasing the core depth of radiator, changing type of tube in the existing radiator, changing flow arrangement, changing fin material, increasing surface area of radiator core and changing the different types of fluids and mixture Article Info Article history: Received 24 January 2018 Received in revised form 10 March 2018 Accepted 20 May 2018 Available online 15 June 2018 Keywords- Heat Transfer Enhancement, Nano-fluid, Thermal Performance, Radiator, Pressure Drop, Convective Heat Transfer Co- efficient