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In many industrial applications, heat must be transferred in the form of either an energy input into the system or removal of energy produced in the system. In this study, heat transfer and flow characteristics of hexagonal finned heat sinks which optimized according to the Taguchi experimental L 18 (2 1 *3 7) design method in channel flow was analyzed numerically. Ansys-Fluent Icepak module was used in CFD analysis. The analysis carried out for two hexagonal finned optimized heat sinks in 3 different fin heights and 5 different flow velocities. Nusselt number increased with increasing Reynolds number for OH-1 and OH-2 heat sinks with all fin heights. Also, results showed that the friction factor decreased with increasing Reynolds number for all fin heights. According to CFD results, Nu-Re and f-Re variations were obtained and compared with experimental results. The experimental results and the numerical results were quite consistent.

Spray cooling process has many parameters such as extended surface, angle of inclination, effect of gravity, diameter of nozzle, angle of spray, mass flux, geometry of cooled surface, thermal performance and critical heat flux of spray etc. Many effective parameters to carry out the experiments with conventional test methods are both expensive and time consuming. As a solution in these circumstances, Taguchi method, which is one of the modern experimental design and optimization methods and very effective in solving such problems, was used in this study. Taguchi method, as well as being in effective to improve the quality of products, also gives the opportunity to achieve better results with much less experiment. Using Taguchi method, as well as to reach the target value exactly, the sensitivity of the design against uncontrollable factors is reduced to a minimum. Thus, the optimum tolerance range in cost and quality factors is determined. When compared to conventional experimental design methods, Taguchi method has many advantages. In these experiments with using rectangular pin fin heat sinks, the effects of the longitudinal and lateral distances of the consecutively arranged nozzle or diffuser-like fin pairs, widths of the fins, angle of fins, heights of fins, spraying time, air flow rate, liquid flow rate (ALR, the ratio of air-liquid flow rate) and the ratio of the nozzle-heat sink distance to the nozzle diameter (h/d) on heat and flow characteristics have been investigated by using Taguchi experimental design method. For this reason, characteristics of flow and heat transfer are considered separately. Nusselt number considered as performance statistic, L27(3 11 ) orthogonal array has been selected as an experimental design plan for the eleven parameters mentioned above. The Nusselt number was calculated by taking into account the characteristic length of heat sink and the optimized results were found to be fin width of 45 mm, fin angle of 45 IntroductionAtomization is used to transfer energy from wide surface areas in low temperatures throughout cooling applications. From the outlet of an atomizer, an unsteady liquid mass performs a fragmentation process respectively in the order of layer formation, ligament formation, and droplet formation. The velocity and diameter rates of the droplets to compose spray are important. When the droplets with a certain speed and diameter range are grouped, the droplet speed and diameter range occur, and these two ranges are fundamental to characterizing the spray. Effective energy transfer is ensured with spray cooling, a technology characterized by high heat transfer, heat convection homogeneity, and a low droplet impact speed, which are explored for engineering applications today. Having gained momentum especially in the last 20 years, studies on the atomization of liquids have been used widely in industry. The cooling of metal surfaces and electronic components, drying operations, humidification, washing, watering and fire extinguishing operations, pulverized f...

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Thanks to the rapid advancement in technology, especially for the systems having high temperatures and high heat fluxes, the interest in studies on impingement jets to improve the cooling efficiency increased in recent years. The current study focuses on determining the optimization of the inclined multijet array to reduce the temperature of electronic devices. In this study, the cooling was performed on the inclined surfaces by making use of impingement multijets via heat sinks consisting of rectangular fins modeled in different geometries and optimum cooling conditions were achieved. In achieving the optimum cooling conditions, the Taguchi method was used since it was thought to offer a reduction in time and costs in industrial applications. In this study, 11 different parameters were examined at three different levels in order to determine the optimum conditions for impingement multijet applications. The Nusselt number was set as the performance characteristic and the L₂₇(3¹¹) orthogonal sequence was used as the experiment plan for 11 parameters that were determined. When calculating the Nusselt number by using nozzle diameter, the optimum results were achieved using the following parameters: 40 mm of nozzle diameter, 9 m/s of air velocity, 20 mm of vertical distance between slices, 4444 W/m² of heat flux, 20 mm of vertical distance between fins, 15 mm of fin width, 30° of fin angle, 15 mm of horizontal distance between slices, 10° of heat sink angle, 20 mm of horizontal distance between fins, and 8 of nozzle diameter/heat sink dimensionless distance ratio. The flat plate and optimum heat sink established using the data obtained were compared under the optimum conditions obtained from the analysis and to the optimum conditions obtained using the finned optimum heat sink and it was determined that, under the optimum conditions, the finned heat sink improved the heat transfer by 28.61% when compared to the flat plate.