Do you know' Automobile fan 】 Why the phenomenon of the wind?
car fans, because of its width is not restricted in theory, and the advantages of big air volume, small dimension, in the cleaning of agricultural materials and some other department has been widely used. Although car fan has quite a few scholars studied it, but there are some basic problems to be further discussed. Gas, for example, according to what is twice through the cascade flow, control flow field in the vortex in the impeller is how to form, the gas flow direction depends on what How do you determine the air inlet and air outlet) And so on. To this end, were studied. In order to facilitate observation, photography, and static pressure flow field measurements, is water simulation experiment.
for automobile fan, if the improper design, may produce the wind phenomenon, namely, the outlet of mutual exchange. Therefore, within the tank is simulated experimental study.
the boundary of the automobile fan ( The shell) , tubular fan is generally by a curve is gradually increasing with the impeller clearance GF ( After the wall) , a circular or other shape of the volute tongue BD and upper boundary of DE. The length of the volute tongue and the outlet on the boundary of DE Angle & gamma; Have great influence on the performance of the fan. Study found that, when the vortex tongue BD has certain length, vorticity in C1 point, fan can work normally, the fluid flow direction. As vortex tongue and impeller clearance & delta; Decrease of vorticity C1 to move down, reflux. The Angle & gamma; Reduced, fluid is easy to flow along the upper boundary, will also reduce reflux.
( 1) Asymmetry of external boundary ( Including asymmetric and impeller clearance) Is that car fan can make the fluid along a certain direction produces the basic conditions of steady flow.
( 2) When the impeller turns the fluid flow field only one straight line boundaries, in near the border, along the impeller rotation direction zui small gaps in the downstream, impeller form a spiral around the place. Tubular fan spiral towards the direction of rotation and impeller, same vortex strength depends largely on the running speed of the impeller and boundary conditions. The vortex impeller flow field inside and outside primary control.
( 3) If you have multiple boundary, the flow field depends on the border of the comprehensive effect. Vortex in the flow resistance is poor zui larger near the border, and only one spiral.
( 4) For car fans, in order to make its faded the normal work and not against the wind, gouge out compared with the other boundary, vortex tongue place should have a larger flow resistance is poor.
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