CN102352862A - Design method of double helix mixed flow pump impeller - Google Patents

Abstract

The invention provides a design method of a double helix mixed flow pump impeller. The method is characterized by providing the design formulas of such main geometric parameters of the impeller as impeller inlet diameter D1, impeller hub diameter dh, maximum impeller outer diameter D20, outlet edge slant angle alpha 2, minimum impeller outer diameter D2h, outlet edge width b2 and impeller axial length L. The design method has the following beneficial effects: not only does the impeller designed by the method meet the requirement of sewage treatment, but also the impeller balance effect can be improved, the vibration and noises during pump operation can be reduced, and the flow capacity and non-destruction and non-winding properties of the mixed flow pump are improved; and therefore the helix mixed flow pump applying the impeller is especially suitable for the sewage treatment industry.

Description

A kind of double helix mixed-flow pump impeller design method

Technical field

The present invention relates to a kind of design method of mixed-flow pump impeller, particularly a kind of double helix mixed-flow pump impeller design method.

Background technique

Mixed flow pump structure and performance are a kind of absorption centrifugal pump and axial-flow pump advantage between axial-flow pump and centrifugal pump, compensate the idealized pump type of two aspect shortcomings.At present, characteristic of centrifugal pump design method, i.e. velocity coefficient method are adopted in the design of the waterpower of mixed flow pump mostly; Adopt cylinder blade or twisted blade, have stronger conveyance capacity, but if use the blowdown pumping plant; Water quality is complicated, and silt is many, and foreign material are many; Cause impeller blade to twine foreign material easily, stop up, cause outer end mechanical seal distortion; Cause mechanical seal to be lost efficacy, the motor water inlet, pump is frequently reported to the police; Increase maintenance frequency, even burn out motor.Thereby, adopt the mixed flow pump of cylinder blade or twisted blade can not satisfy the condition of under complex environment, moving.

Do not take place to twine and stop up for mixed flow pump can be moved under the operating mode of complicacy, need to adopt the screw type blade, and for guaranteeing its conveyance capacity, the number of blade can not be too much.Because its structural feature of mixed flow pump of single-screw blade has determined the nonsymmetry of its shape, its non-uniform mass.When wheel rotation, just produce unbalanced centrifugal inertia force, thereby make the pump housing produce vibration and noise, the not stationarity when having increased pump operation.The impeller that this just requires us to design can improve mobility status, and good static balancing effect is arranged again.

Summary of the invention

For solving the deficiency of existing mixed-flow pump impeller performance, the invention provides a kind of double helix mixed-flow pump impeller design method.Utilize following relation to confirm the main geometric parameters of impeller, mainly comprise: inlet diameter D ₁, the impeller hub diameter d _h, impeller maximum outside diameter D ₂₀, outlet limit inclined angle alpha ₂, impeller minimum outer diameter D _2h, outlet hem width degree b ₂With the impeller axial length L.Not only satisfy the needs of sewage treatment with the impeller of the present invention design, have good static balancing effect, improved conveyance capacity and the non-destructive of mixed flow pump, no winding performance simultaneously again.Therefore, the spiral mixed flow pump of using this kind impeller is particularly suitable for sewage treatment industry.Realize that above-mentioned purpose adopted technological scheme:

1, the inlet diameter D of impeller ₁

Its formula $D_1=K_0\sqrt[3]{Q/n};$

In the formula: D ₁-impeller inlet diameter, rice;

The flow of Q-design conditions, cube meter per second;

The n-wheel speed, rev/min;

K ₀-correction factor, K ₀=(4～6.5).

2, hub diameter d _h

Its formula: d _h=14..41+0.08n _s

In the formula: d _h-impeller hub diameter, rice;

n _s-specific speed, rev/min.

3, impeller maximum outside diameter D ₂₀

Its formula: $D_{20}=K_1{\left(\frac{n_s}{100}\right)}^{-0.225}\sqrt[3]{Q/n};$

In the formula: D ₂₀-impeller maximum outside diameter, rice;

K ₁-correction factor, K ₁=(6.5～10.5);

n _s-specific speed, rev/min;

The flow of Q-design conditions, cube meter per second;

The n-wheel speed, rev/min.

4, impeller outlet width b ₂

Its formula: $b_2=K_2{\left(\frac{n_s}{100}\right)}^{0.61}\sqrt[3]{Q/n};$

In the formula: b ₂-impeller outlet width, rice;

K ₂-correction factor, K ₂=(6～8.5);

The flow of Q-design conditions, cube meter per second;

n _s-specific speed, rev/min;

The n-wheel speed, rev/min.

5, impeller axial length L

Its formula: L=(0.9～1.05) D ₂₀

In the formula: L-impeller axial length, rice;

D ₂₀-impeller maximum outside diameter, rice.

6, impeller cornerite φ

Impeller cornerite φ=200 °～550 °.

7, outlet limit inclined angle alpha ₂

Outlet limit inclined angle alpha ₂=10 °～40 °.

8, impeller minimum outer diameter D _2h

Its formula: D _2h=D ₂₀-b ₂Tan α ₂

In the formula: D _2h-impeller minimum outer diameter, rice;

D ₂₀-impeller maximum outside diameter, rice;

b ₂-impeller outlet width, rice;

α ₂-outlet tilt angle, limit, degree.

9, blade exit laying angle β ₂

Blade exit laying angle β ₂=5 °～25 °, specific speed gets the small value greatly.

The invention has the beneficial effects as follows: can improve the impeller counterbalance effect, vibration when reducing pump operation and noise.

The present invention is on probation through the user, and reaction effect is good.

Description of drawings

Fig. 1 is the impeller axial plane figure of one embodiment of the invention.

Fig. 2 is same embodiment's an impeller blade planimetric map.

Among Fig. 1: 1. impeller inlet diameter D ₁, 2. hub diameter d _h, 3. helical blade, 4. wheel hub, 5. axis hole, 6. impeller maximum outside diameter D ₂₀, 7. outlet limit inclined angle alpha ₂, 8. export hem width degree b ₂, 9. impeller axial length L, 10. impeller minimum outer diameter D _2h

Among Fig. 2: 4. wheel hub, 11. impeller outlet laying angle β ₂, 12. subtended angle of blade φ, 13. impeller inlet limits, 14. impeller outlet limits.

Embodiment

Fig. 1 and Fig. 2 have confirmed this embodiment's impeller shape jointly.It and common mixed-flow pump impeller are different, and impeller inlet is the spiral protrusive type, and inlet side (13) looks that just as the reaping hook shape blade (3) rises along wheel hub (4) spiral, and its blade (3) number has only two, and the blade of symmetric arrangement has good counterbalance effect.And possess very big runner, have good performance and the non-destructive of passing through.The present invention confirms impeller inlet diameter D through following relation ₁(1), impeller hub diameter d _h(2), impeller maximum outside diameter D ₂₀(6), outlet limit inclined angle alpha ₂(7), outlet hem width degree b ₂(8), impeller axial length L (9) and impeller minimum outer diameter D _2h(10).

$D_1=K_0\sqrt[3]{Q/n};$

d _h＝14..41+0.08n _s；

$D_{20}=K_1{\left(\frac{n_s}{100}\right)}^{-0.225}\sqrt[3]{Q/n};$

$b_2=K_2{\left(\frac{n_s}{100}\right)}^{0.61}\sqrt[3]{Q/n};$

L＝(0.9～1.05)D ₂₀；

φ＝200°～550°；

α ₂＝10°～40°；

D _2h＝D ₂₀-b ₂tanα ₂

β ₂＝5°～25°。

In the drawings, blade exit laying angle (11) chooses and specific speed n _sSize relevant, specific speed is big, the outlet laying angle (11) get the small value.Subtended angle of blade is according to the casting and the difficulty or ease situation and the performance requirement of sand removal, between φ=200 °～550 °, chooses.

Claims (1)

1. a single-screw mixed-flow pump impeller design method provides blade main geometric parameters inlet diameter D ₁, hub diameter d _h, maximum outside diameter D ₂₀, outlet limit inclined angle alpha ₂, impeller minimum outer diameter D _2hWith outlet hem width degree b ₂Design formula.It is characterized in that: be fit to following relation between impeller geometric parameter and the pump design conditions point performance parameter:

$D_1=K_0\sqrt[3]{Q/n};$

d _h＝14..41+0.08n _s；

$D_{20}=K_1{\left(\frac{n_s}{100}\right)}^{-0.225}\sqrt[3]{Q/n};$

$b_2=K_2{\left(\frac{n_s}{100}\right)}^{0.61}\sqrt[3]{Q/n};$

φ＝200°～550°；

α ₂＝10°～40°；

D _2h＝D ₂₀-b ₂tanα ₂

β ₂＝5°～25°。

In the formula: Q-design conditions point flow, cube meter per second;

D ₂₀-impeller maximum outside diameter, rice;

D _2h-impeller minimum outer diameter, rice;

b ₂-impeller blade exit width, rice;

β ₂-impeller blade outlet laying angle, degree.

The n-wheel speed, rev/min;

n _s-specific speed, rev/min;

φ-impeller blade cornerite, degree;

α ₂-exit edge of blade tilt angle, degree.

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