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A Review of Surface Coating Technology to Increase the Heat Transfer International Journal of Mechanical Engineering and Robotics Research Vol. 7, No. 5, September 2018 A Review of Surface Coating Technology to Increase the Heat Transfer S. Pungaiya Department of Mechanical Engineering, Valliammai Engineering College, Chennai, Tamilnadu, India. Email: [email protected] C. Kailasanathan Department of Mechanical Engineering, Sethu Institute of Technology, Virudhunagar, Tamilnadu, India. Abstract---Heat dissipation is one of the paramount application because of the need for external power in considerations in IC engine design. Loss of heat is many practical applications. Augmentation of heat encouraged only in an automobile to keep the engine transfer by this method can be achieved by Mechanical safe. In this paper, a review of the current status of avails, surface vibration, fluid vibration, electrostatic the research and technological development in the fields, injection, suction and jet impingement. [4]. field of thermal spray coating process by utilization of Passive techniques generally use surface or Nanomaterials. Generally, the thermal spray concept geometrical modifications to the flow channel by is used for improving wear resistance, corrosion incorporating inserts or adscititious contrivances They resistance, and thermal barrier properties of metals. promote higher heat transfer coefficients by perturbing or However, no significant attempts have been made to altering the subsisting flow demeanor like treated improve thermal conductivity by thermal spray surfaces, rough surfaces, elongated surfaces, displaced technology. This paper is focused on the limitation of enhancement contrivances, swirl flow contrivances, existing heat transfer in Automobile radiator and how coiled tubes, surface tension contrivances, additives for the thermal spray Nano coating will improve the heat liquids and additives for gases. In these techniques, transfer in an Automobile radiator. passive techniques are more considerable because active Index Terms—Nano coating, thermal spray, heat transfer, techniques are more intricate from the design perspective. surface coating In recent trends, it has been found that a paramount heat transfer enhancement may be achieved while utilizing I. INTRODUCTION Nanofluids (passive technique-additives for liquids) [4]. Nanoparticles (<100nm) suspension in conventional An Internal Combustion engine engenders enough heat fluids is called as Nanofluids which have higher thermal to ravage itself. Without an efficient cooling system, we conductivity when compared to conventional base fluids would not have the conveyances today. The abstraction because of suspended solid particles. It conducts more of extortionate heat from IC engine is essential to eschew heat from IC engine, but the deficient rate of heat overheating or burning. An automotive cooling system dissipation in automobile radiator it may fail to achieve must perform several functions.. a) Remove excess heat the desired rate of heat dissipation[5,6,7]. In thermal from the engine. b) Maintain a consistent engine perspective, if we opted to increment the heat transfer, temperature. c) Help a cold engine warm up quickly. then we require incrementing the heat transfer area. So Generally, the heat transfer from surfaces may be we require an immense size radiator to dissipate more enhanced by increasing the heat transfer coefficient heat but the current trends we require a more puissant between a surface and its surroundings, by increasing the engine in a minuscule hood space. This review shows heat transfer area of the surface, or by both. There are that the present status of the research and technological several ways to enhance the heat transfer characteristics, development in the field of Nano coating of thermal which can be mainly divided into active and passive spray technology for ameliorating the heat dissipation in techniques. [1-3]. automobile radiator are discussed. Active techniques are more compact to utilize and design aspect. As the method requires some external II. THERMAL SPRAY TECHNOLOGY power input to cause the desired flow modification and improvement in the rate of heat transfer. It finds finite The invention of the first thermal spray process is generally attributed to M.U. Schoop of Switzerland in 1910[8] and is now kenned as flame spraying. Other Manuscript received July 6, 2018; revised August 9, 2018. © 2018 Int. J. Mech. Eng. Rob. Res 458 doi: 10.18178/ijmerr.7.5.458-465 International Journal of Mechanical Engineering and Robotics Research Vol. 7, No. 5, September 2018 thermal spray processes include wire spraying, they are heated above their melting point[9]. Thermal detonation gun deposition invented by R.M. Poorman, spraying techniques are coating processes in which H.B. Sargent and H. Lamprey and patented in 1955. melted (or heated) materials are sprayed onto a surface. Plasma spray process invented by R.M. Gage, O.H. The feedstock is heated by electrical (plasma or arc) or Nestor, and D.M. Yenni patented 1962, and high-velocity chemical means (combustion flame). Thermal spraying oxyfuel is invented by G.H. Smith, J.F. Pelton and R.C. can provide thick coating (20µm to several mm Eschenbach and patented in 1958. Thermal spray is the approx.)over a sizable area at high deposition rate as generic term for a group of processes in which metallic, compared to other coating processes. The overview of the ceramic and some polymeric materials in the form of thermal spray process is shown in Fig. 1. powder, wire or rod are alimented to a gun with which, Figure 1. Thermal spray process overview. Thermal spray coatings are customarily composed by droplet is between 5µm to 100µm. When the droplets are multiple passes of a spray gun over the surface. Thermal in the air stream, they don’t have the time to cool down. spray technology consists of fusing a material in a The droplets are cooling down only when they impact the thermal spray unit and atomizing the fused droplets of substrate. At impact, they immediately bond at the material. These fused droplets of molten material are surface of the substrate. It is shown in Fig. 2. The sprayed onto the component to be coated. The size of the thermal spray process flow denoted in Fig. 3. Figure 2. Thermal spray coating © 2018 Int. J. Mech. Eng. Rob. Res 459 International Journal of Mechanical Engineering and Robotics Research Vol. 7, No. 5, September 2018 III. THERMAL SPRAY PROCESS FLOW CHART Surface Preparation Cleaning and Pre Processing Decreasing Masking Surface Roughening Thermal Spray Process Process Finishing Treatment Sealing Coating and Post Processing Finishing Coating Repair Quality Assurance Metallography Properties and Hardness Quality Checking Testing Bond Strength Testing Figure 3. Thermal spray process flow chart. © 2018 Int. J. Mech. Eng. Rob. Res 460 International Journal of Mechanical Engineering and Robotics Research Vol. 7, No. 5, September 2018 fin efficiency. Whether entrance and exit loss should be IV. LITERATURE SURVEY included. Joshua A. Gordon et al., (14) has design and simulation of both passive and active plasmonic coated Anand Kumar Dubey, (10) focused on the efficiency spherical nanoparticles. This behavior must be contrasted of the internal combustion engine cooling system with a classical laser, where lasing is maintained as the depends mainly on the performance of its units. The main gain is increased its past threshold value. It is believed unit in this system is the radiator. The aluminium radiator that the passing turns-off when the gain increases to such is able to perform same as a copper radiator with some a point that it causes a severe detuning of the structural design modification, increasing the surface area of heat resonance. Explained about on/off nature of the super transfer & it can replace the copper radiator in the respect resonance, the authors are currently investing both lossy of the performance, heat transfer, cost-competitive & passive and active CNP with a virtual mode analysis. lightweight. Painting of tubes & fins is more sensitive & Tariq Shamim et al.,(15) discussed combustion assisted required in copper radiator due to corrosion and oxidation thermal spray systems by the numerical investigation. problem, but in case of an aluminium radiator, it is not so The gas phase temperature, velocity, and pressure were serious because scaling, oxidation & corrosion is not so found to depend on a series of parameters, including effective in the performance of radiator. Due to impurity mass flow rate of the gas phase, fuel/oxygen ratio, in coolant used in radiator & continuous corrosion after reactant preheating and cooling rate. The actual effects of aging the tubes got punctured & leakage problem started those parameters are different in different parts of the in the field actual application; the reworking of these nozzle and the region outside of the nozzle. The gas tubes is easy by a brazing process in the case of phase properties have a strong influence on the particle aluminium radiator than copper radiator but changing of temperature and velocity and also concluded that a tubes is very difficult in Aluminium radiator which is a particle does not start losing temperature when the gas major drawback of an aluminium radiator. David J. et phase temperature experienced a decrease since the al., (11) Carried work on the compact heat exchangers. reduced gas temperature is still significantly higher than A visualization study was performed to inspect fouling the particle temperature. The particle
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