Fan Airflow
Ideen Sadrehaghighi2023, CFD Open Series
https://doi.org/10.1017/cbo9780511800955AI-generated Abstract
This paper focuses on the principles and distinctions between fans, blowers, and compressors in the context of their operational mechanics and applications. It defines key terms and pressure ratios associated with each device, elucidating the specific conditions under which they operate and the role of pressure rise in their functionality. Additionally, the paper highlights the significance of these distinctions for practical applications in industrial and everyday contexts.
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Figures (58)
![reiterated into momentum theory. If a feasible propeller geometry is used this method rapidly converges to a solution. The induced flow speed can be obtained by reiteration of the thrust and torque determined from the 2D section into momentum theory. Convergence of the solver can be tested by different variables with common choices: the angle of attack, angle ~ or the induction factor. The method described below solves for axial and tangential induction factors via and vi. a and B are Angle of attack and geometric airfoil section pitch angle, respectively. U. denotes free stream velocity. For more details, please consult the chapter 3 of [Teeuwen ]¢.](https://figures.academia-assets.com/104006058/figure_006.jpg)
![A combination of anisotropic and isotropic triangles were used in the surface mesh discretization. Areas of high curvature - such as the leading edge, trailing edge, and the tip were resolved by utilizing Pointwise’s T-Rex algorithm. This tool grows anisotropically stretched, right-angled triangles layered in the normal direction to a boundary [5], as shown below. Using this, areas of high curvature are able to be resolved without the need to isotopically refine the area. The result is an accurate adherence to the surface and a reduction in the point count. The interior of the surface mesh was resolved with isotropic triangles created using a modified Delaunay algorithm. (Figure 3.3.2).](https://figures.academia-assets.com/104006058/figure_034.jpg)
![ee a resulting in an additional source term qcae besides the continuity source term q., the momentum source term qm, and the energy source term qe. Note that the APE are formulated in a rotating frame of reference. The time-dependent rotation of the reference frame is only accounted for by adding the Coriolis acceleration term in the momentum equation [20]. Because of the extension to a non- uniform mean flow field, convection and refraction effects are taken into account by the left-hand side operator. The results from the large-eddy simulation determine the mean ow quantities and the sources To accurately resolve the acoustic wave propagation described by the APE-4 formulation, the acoustic perturbation equations are discretized in space using the 9-point 6 order dispersion- relation preserving (DRP) scheme proposed by Tam & Webb [21] in the interior domain of integration and a special formulation of the DRP summation by parts scheme (SBP-DRP)[22] on the boundaries. A 4 order alternating 5-6 stage low-dissipation and low-dispersion Runge-Kutta method originally proposed by Hu et al.,[23] and modified by Stanescu and Habashi [24] is applied for the temporal integration. A detailed description of the two-step method and the discretization of the Navier-Stokes equations and the acoustic perturbation equations is given by Ewert and Schroder [25].](https://figures.academia-assets.com/104006058/figure_039.jpg)
![Figure 3.4.3 illustrates the performance curve of the axial fan showing the pressure coefficient P= Ap/[(t2/2) pD2.n2] versus the flow rate coefficient = 4V/(m2D3,n) for the tip-gap width s/D, = 0.001, s/Do = 0.005, and s/Do =0.01, where Ap = Pstatout- Po,in is the difference of the static pressure at the outlet pstatourand the stagnation pressure at the inlet pojn.](https://figures.academia-assets.com/104006058/figure_041.jpg)
