| 内容提要: |
The influence of guide vane of exhaust (GVE),
diameters of outer cylinder and diffuser, impeller geometric parameters, on a
novel range hood aerodynamic performance is investigated in this report by
computational fluid dynamic, which has different operation principle in
comparison with other kind of traditional range hood with centrifugal fan. The
pressure field and characteristic curves based on the dimensionless flow,
pressure and power coefficients of the novel range hood are analyzed. Results
show that the pressure and power coefficients first increase then decrease with
the increasing number of GVE. It can help to improve the flow characterizes
efficiently when the height of GVE is lower than 0.20 m, but the effect of GVE
height on flow and pressure coefficients may be negligible at the height of GVE
above 0.20 m. The pressure distribution in annular indicates that the diameters
of outer cylinder and diffuser are 0.40 m and 0.320 m, respectively, which can
effectively enhance the diffusion performance of the novel range hood. When
blade inlet and outlet angular is smaller than 65° and 175°, the suction
capacity of the novel range hood is enhanced with the increasing of inlet and
outlet angular, respectively, based on the static pressure field in impeller
and annular. As blade less than 28, the effect of blade number on coefficients
of flow and pressure is remarkably. However, when the blade number is more than
30 blades, the characteristic curves for dimensionless flow and pressure
coefficients exhibit downtrend simultaneously. In addition, the static pressure
in blade passage of the impeller increases notably with the growth of blade
height, when the blade height is lower than 0.200 m, while the improvement for
static pressure is relatively minor when the blade height is higher than 0.200
m. |