Volute molded line generation method of centrifugal fan

A centrifugal fan and volute technology, which is applied in the field of volute profile generation of centrifugal fans, can solve the problems of generating irregular noises, having little guiding significance for the actual design of the volute, and unsmooth flow field at the multi-section splicing splicing. The effect of reducing noise and smooth flow field

Active Publication Date: 2020-07-28
NINGBO FOTILE KITCHEN WARE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The above volute profile is obtained by using multi-segment splicing or using the three-point method to draw a smooth curve, but the flow field at the multi-segment splicing joint is not smoot...

Method used

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  • Volute molded line generation method of centrifugal fan
  • Volute molded line generation method of centrifugal fan
  • Volute molded line generation method of centrifugal fan

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] The above formula (1) is improved as:

[0047]

[0048] Where C is a constant: 02 ,D 2 is the diameter of the base circle of the volute.

[0049] Thus, see figure 1 , the profile equation of the basic profile L1 is r=117*exp(0.077*θ / 180*π), and through the method of this embodiment, the outer circle of the volute profile is overall increased, and its profile equation is: R =(117+3)*exp(0.077*θ / 180*π).

Embodiment 2

[0051] The method in the above-mentioned embodiment 1, when the size is limited and the flow rate variation range is large, will cause obvious attenuation at low flow rates.

[0052] Therefore, in this embodiment, the C in the first embodiment is changed so that it is no longer an invariable constant, but is changed to a variable that gradually decreases from the starting point to the end point of the profile line. While the gap at the cochlear tongue is large, the overall width is not increased, and the impact on small flow attenuation is reduced.

[0053] One way is to make C vary linearly. At the start point (θ=0°) of the volute profile, C=3, and at the end point (θ=360°), C=0. In this embodiment, C changes linearly from the starting point to the ending point. Specifically, it can be expressed as:

[0054]

[0055] see figure 2 , the innermost one is the base profile L1, the outermost one is the volute profile L2 obtained in Example 1, and the middle one is the volute ...

Embodiment 3

[0064] In the actual optimization design process, refer to the above formula (2): The value range of m is generally larger. In order to adapt to such a wider range of changes in the value of m, in this embodiment, this is further optimized. The radius of the base circle remains unchanged, and only the value of m is changed. From the perspective of noise reduction, m adopts the method of gradually decreasing from the starting point to the ending point, that is, the gap at the cochlear tongue increases.

[0065] Taking a certain type of range hood currently on the market as an example, the maximum efficiency point m is 0.065, and the maximum air volume point m is 0.095. m gradually decreases from the start point to the end point of the volute profile. One way is to make m vary linearly. At the start point (θ=0°) of the volute profile, m=0.095, and at the end point (θ=360°), m=0.065. Another method is to make m change nonlinearly, and the nonlinear change can also be divided...

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Abstract

The invention discloses a volute molded line generation method of a centrifugal fan. The method comprises the following steps that 1, a basic molded line is obtained according to a logarithm spiral line equation, wherein Q is the design flow of a volute, R2 is the radius of a volute base circle, c '< 2 > u is the tangential component velocity of a limited blade under the actual condition, and theta is the polar angle; the method is characterized by further comprising the following steps that (2) a basic molded line R = R2emtheta is obtained; and 3) increasing the radius of the base circle and/or changing m so as to increase the volute tongue gap of the volute to obtain the volute molded line. Compared with the prior art, the method has the advantages that by increasing the radius of the base circle of the volute molded line or changing m, the overall width can be kept unchanged to guarantee flow while the volute tongue gap is increased and noise is reduced, a section of smooth transition curve is generated on the basis of an original spiral line by combining fluid mechanics knowledge and a volute design theory and tightly combining with reality, and a flow field is smooth.

Description

technical field [0001] The invention relates to a power device, in particular to a method for generating a volute profile line of a centrifugal fan. Background technique [0002] The role of the centrifugal fan volute includes two points, one is to collect the fluid flowing out of the impeller, and the other is to convert the kinetic energy of the high-speed fluid flowing out of the impeller into the required potential energy. The volute profile is the boundary that constrains the fluid movement inside the volute, and it also determines the position of the volute tongue and the size of the volute tongue gap, which has a great impact on the diffusion performance of the volute. [0003] The volute tongue is a key part that affects the noise and backflow of the entire fan system. There is only one recommended clearance value in the general design method: For household appliances, the commonly used volute base circle diameter D 2 The size of the worm tongue is between 50 and 50...

Claims

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Application Information

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IPC IPC(8): G06F30/17F04D29/42
CPCF04D29/4226
Inventor 宁国立
Owner NINGBO FOTILE KITCHEN WARE CO LTD
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