Forward-curved multi-wing type centrifugal fan

Abstract

The invention discloses a forward-curved multi-wing type centrifugal fan. The forward-curved multi-wing type centrifugal fan comprises a volute casing and an impeller, wherein the volute casing comprises a volute tongue as well as a first curved surface, a second curved surface and a third curved surface which are sequentially tangential and are smoothly connected, wherein the impeller and the volute casing are arranged in an eccentric manner for increasing the diameter of the impeller. According to the forward-curved multi-wing type centrifugal fan, the impeller is mounted in the eccentric manner relative to the volute casing, so that the diameter of the impeller is increased, parameters such as air quantity, air pressure and the like are obviously improved, noises are reduced, fan surge is avoided, and the performances of the fan are improved; and meanwhile, three sections of cambered surfaces form the volute casting, so that the profile of the volute casting is simplified, the space volume is saved, the structural form is simple, a welding process is avoided and the processing cost is low, and therefore, the volute casting is more convenient to manufacture.

Description

technical field [0001] The invention relates to the field of air conditioning and ventilation, in particular to a forward-curved multi-blade centrifugal fan, especially suitable for small forward-curved multi-blade double-suction centrifugal fans. Background technique [0002] The multi-blade centrifugal fan has the advantages of large flow coefficient, high pressure coefficient, small size coefficient and relatively low noise, and is widely used in the air-conditioning industry. The forward curved multi-blade centrifugal fan is a kind of centrifugal fan and belongs to the blade fan. The main feature of this fan impeller is the use of forward curved blades with a large wheel diameter ratio (0.8~0.95), relatively large width (about 0.4 times the outer diameter of the impeller), and a large number of blades (32~64). The air inlet of the volute is fitted with the impeller in a gap type, and the axial gap value is generally 0.02~0.025 times the outer diameter of the impeller. ...

AI Technical Summary

Problems solved by technology

Its work efficiency is relatively low, which limits its scope of use to a certain extent

In order to improve the efficiency of the multi-blade centrifugal fan, the traditional equal-thickness single-arc straight blades are changed into airfoil blades, trapezoidal blades or twisted blades, but it is not easy to determine a reasonable optimization scheme, and it causes complex structure, difficult processing, The cost is too high and the practical value is not great

[0004] The volute design of the multi-blade centrifugal fan for air conditioning cannot fully refer to the design methods and empirical data of industrial fans. The coincidence of the impeller and the geometric center of the volute may not be the best installation position, and the traditional volute profile may not be the most reasonable.

However, the two-dimensional design theory of the inner wall of the volute and the variable helix angle design theory proposed by some researchers based on this are too complicated and poor in operability

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