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+--- Thread: Numerical Study of Aeroacoustic Sound on Performance of Bladeless Fan (/showthread.php?tid=336)
Numerical Study of Aeroacoustic Sound on Performance of Bladeless Fan - fftty120 - 08-24-2021
Aeroacoustic performance of fans is essential due to their widespread application. Therefore, the original aim of this paper is to evaluate the generated noise owing to different geometric parameters. In current study, effect of five geometric parameters was investigated on well performance of a Bladeless fan. Airflow through this fan was analyzed simulating a Bladeless fan within a 2 m×2 m×4 m room. Analysis of the flow field inside the fan and evaluating its performance were obtained by solving conservations of mass and momentum equations for aerodynamic investigations and FW-H noise equations for aeroacoustic analysis. In order to design table bladeless fan Eppler 473 airfoil profile was used as the cross section of this fan. Five distinct parameters, namely height of cross section of the fan, outlet angle of the flow relative to the fan axis, thickness of airflow outlet slit, hydraulic diameter and aspect ratio for circular and quadratic cross sections were considered. Validating acoustic code results, we compared numerical solution of FW-H noise equations for NACA0012 with experimental results. FW-H model was selected to predict the noise generated by the Bladeless fan as the numerical results indicated a good agreement with experimental ones for NACA0012. To validate 3-D numerical results, the experimental results of a round jet showed good agreement with those simulation data. In order to indicate the effect of each mentioned parameter on the fan performance, SPL and OASPL diagrams were illustrated.
There are two typical fans widely used: axial and radial types, however Bladeless fans are completely distinct from those fans in mechanism aspect. Bladeless fan is similar to centrifugal fans in terms of radial impellers for intake air and also it is similar to axial fans in terms of preparing higher rate of outlet airflow. Although studies about wall and table bladeless fan are rare in the literature, numerous experimental and numerical studies have been performed on the axial and centrifugal fans. Lin, et al [2], designed a Forward–Curved (FC) centrifugal fan by numerical simulation and
to calculate the noise propagation of smart bladeless fan. Firstly, the generated noise of a NACA 0012 airfoil is computed to validate aeroacoustic results by experimental data [17]. The obtained numerical results and the experimental data are in the reasonable agreement, so the FW-H model is employed to measure the tonal noise of Bladeless fan. To validate 3-D numerical simulations, the experimental results of a round jet [18] are compared with numerical simulation behind and surrounding air toward front of fan. Therefore, a smart tower bladeless fan amplifies the intake air by drawing the air behind and around the fan. Thereby the inventor of this fan claims that [1] this fan multiplies intake air at about 15 times at distance 3D front of fan (around 1000-1200 mm) [1, 19]. All of described stages are shown in Fig.