Elektronik kutular için bir eksenel akış fanının performans karakterizasyonu ve optimizasyonu

Thermal management of high power electronic components have become a challenging and critical issue for thermal engineers. Forced convection electronic enclosures comprises of fans to provide fluid flow through the system to remove heat efficiently. In this study, performance characterization of an axial fan for electronic enclosures has been performed computationally and experimentally. For this purpose, by using the three-dimensional CAD model of a fan with Computational Fluid Dynamics (CFD) are evaluated in comparision with the experimental data. An experimental system was designed and built for the validation of numerical models. All the measurements were carrried out in a wind tunnel which was designed and manufactured according to the Air Movement Control Assosciation (AMCA) standard 210-99, 1999. In order to make relevant comparisions, a detailed computational model of the wind tunnel setup along with the fan were modeled. Moving Reference Frame (MRF) technique is used for the modelling of an axial fan and the simulations were performed by utilizing realizable k–ε turbulence model with enhanced wall function to determine flow and pressure fields over a range of flow rates. Experimental investigation in the wind tunnel by measuring the pressure rise and flow rate through the fan by using multiple nozzles which was also designed and manufactured according to the Air Movement Control Assosciation (AMCA) standard 210-99, 1999. Understanding of the overall fan efficiency as a function of the volumetric flow rate and th improvement concerning with the losses occur across the fan are described. In the second phase of the study, power losses of an axial fan are investigated to determine the effect different components on the overall efficiency. Moreover, it deals with the modeling of mechanical, electrical, thermal and electromagnetic losses which focus especially on an outer rotor brushless DC motor. Efficiency of a fan depends on its electrical and mechanical designs as well as the environmental conditions that the fan is exposed to. Typically, the overall efficiency of an axial fan varies between 15 to 40 percent. Power losses may be due to electrical, aerodynamic or mechanical design components. Losses occurring in an axial fan motor have become a critical issue in which high inertial effects, low power, low cost and high efficiency are desired. In order to design an efficient motor, it is important to accurately predict the power losses which are usually dissipated in the form of heat. Reduction of these losses leads to a decrease in the motor temperature and, therefore, has a positive effect on the fan reliability. Expressions for calculating the inverter losses, motor losses and mechanical losses are derived. The power losses obtained are then used as heat sources when evaluating the thermal performance of the motor. By using a two-dimensional model, computational fluid dynamics (CFD) simulations are performed to analyze the core loss distribution across the motor. The results are utilized to determine evaluate the overall efficiency of the system.