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Yayın Effect of the computational domain selection on the calculation of axial fan performance(International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016, 2019) İlikan, Ayhan Nazmi; Ayder, ErkanIn this study, the aerodynamic performance of a jet fan (considered as a free-inlet free-outlet axial fan which does not contain any duct at the upstream or downstream) is obtained by using CFD (Computational Fluid Dynamics) method. The numerical calculations are performed by using the commercial software ANSYS CFX. Three different inlet and outlet computational domain shapes that are widely used for simulations of axial flow fans are evaluated. In the first method, the fan is modeled inside a circular pipe. The second approach does not contain the domain of a pipe at the inlet and the outlet but large inlet and outlet domains connected instead directly to the fan casing. The third method is similar to the second approach except a bellmouth located at the inlet of the fan that is not present in the second approach. The aerodynamic performance of the fan at atmospheric conditions is obtained by three approaches and the results are compared to each other and to the ones obtained experimentally. The results show that the simulation of a jetfan as if it works in a pipe brings an error of 45 % in flowrate which can be decreased to 25 % by placing a bellmouth at the intake of the fan casing.Yayın A quasi-one-dimensional bubbly cavitating flow model and comparison with experiments(European Turbomachinery Soc-Euroturbo, 2011) Delale, Can Fuat; Başkaya, Zafer; Pasinlioğlu, Şenay; Şen, Mete; Ayder, ErkanA bubbly cavitating flow model is constructed for unsteady quasi-one-dimensional and two-dimensional nozzle flows. In each case, the system of model equations is reduced to evolution equations for the flow velocity and bubble radius and the initial and boundary value problems of the evolution equations are formulated. The rest of the flow variables are then related to the solution of the evolution equations. Nozzle flow experiments are also carried out using water. The static wall pressures are measured at different locations of the nozzle and the partial cavitation cloud cycle is recorded using a high speed camera. Results of the numerical simulations obtained for quasi-one-dimensional nozzle flows, seem to capture the measured pressure losses due to cavitation, but they turn out to be insufficient in describing the two-dimensional cavitation cloud structures, suggesting the need for two-dimensional numerical solution of the model equations.
