EVALUATION OF HEAT TRANSFER INCREASE ACCORDING TO THE DISTANCE OF THE FIN FROM THE IMPINGING JET INLET IN COMBINED JET FLOW CHANNELS USING TIO2-WATER NANOFLUID
Özet
Today, when the transition of world countries to green energy is discussed, the method of obtaining energy and reducing the amount of use in all kinds of sectors are among the most important and crucial issues. The increase in the cost of energy affects the production costs, especially in the heat-intensive industry. However, the increase in the amount of heat production per unit volume in electronic devices whose dimensions have decreased with the development of technology; this is undesirable for the progress process in the sector. The cross-flow cooling method, which is used to increase heat transfer from electronic elements, is one of the most widely used methods. This method is based on the principle of sending the cold fluid over all the components with a fan, thereby cooling the entire electronic components. Another method of heat transfer is impinging jet cooling where cold fluid is locally sprayed onto an element with a high temperature with a nozzle. For this reason, it is difficult to reach the conditions that can keep the whole circuit safely with a single type of cooling method. Implementing the impinging jet and cross flow cooling method together can create a beneficial situation with high cooling capacity. When the literature is evaluated, it is seen that the number of combined jet flow studies in which impinging jet and cross flow are applied together using TiO2-Water nanofluid, which exhibits high heat transfer performance, is quite low. In this study, heat transfer and flow structures in channels, which are cube and cavity models, were numerically investigated using water and TiO2-Water nanofluids in H=3D height channels with combined jet flow with 30o and 60o angled fins. The fins are located at N=D and N=2D positions from the impinging jet inlet. Numerical analysis was carried out by solving the energy and Navier-Stokes equations with the k-
using the Ansys-Fluent program in a three-dimensional and steady. While the upper and lower surfaces of the fin and channel are adiabatic; a constant heat flux of 1000 W/m2 was applied to the model surfaces. The Reynolds number range studied for fluids is 5000-9000. Thermophysical properties of 2% volumetric concentration TiO2-Water nanofluid were obtained with the help of equations found in the literature. The results of the study were compared with the correlation obtained as a result of the experimental study in the literature and the results were found to be compatible. The results were analyzed as changes in the mean Nu number for each cube and cavity model surface in the channels.