CN104912851A - Channel type guide valve designing method - Google Patents

Abstract

The invention discloses a channel type guide valve designing method and is mainly applied to solving the problem of low working efficiency of a pump, caused by ignorance of importance of mismatch between a conventional channel type guide valve and an impeller when the conventional channel type guide valve is designed. For the purpose of eliminating the defect, the method, based on the design of the conventional channel type guide valve, determines an inlet width b3 of the guide valve, a throat width a3 of the guide valve and a guide valve number z by use of Anderson' area ratio principle. According to the invention, on the basis of the design of the conventional channel type guide valve, by use of the Anderson' area ratio principle, the inlet width b3 of the guide valve, the throat width a3 of the guide valve and the guide valve number z are determined, and the match between the impeller and the guide valve is taken into consideration, such that the waterpower loss is reduced, the efficiency of the pump is improved, and the purposes of energy conservation and consumption reduction are realized.

Description

A kind of flow channel type guide blade design method

Technical field

The present invention relates to multistage centrifugal pump field, particularly a kind of flow channel type guide blade design method.

Background technique

Along with the development at a high speed of China's economy and the minimizing day by day of global energy, save energy and reduce the cost and become global common focus problem.Pump series products is in the one of fluid machinery series products, and domestic is in great demand, and every annual electricity generating capacity 20%--25% is wasted on pump series products.And multistage centrifugal pump is as common a kind of product.Be widely used in the fields such as industrial production, mine, urban water supply and sewerage, stator is the important component part in each element of multistage pump, is the keypoint part of loss in efficiency in pump flow passage components.The radial stator of many application and flow channel type guide blade in multistage pump, radial stator is simple because of its structure, casts, processing technology is convenient and be widely used.Flow channel type guide blade is made up of several independently closed flow, has good hydraulic characteristic, but its casting, processing technology is more loaded down with trivial details is not widely used.But along with the development of current manufacturing technology and 3-D technology, flow channel type guide blade is applied in some important multistage pumps gradually.

Design method and the radial stator of flow channel type guide blade are similar.Traditional design method first determines stator axial plane entrance width, stator throat width is estimated by stator axial plane entrance width, the number of blade is obtained again by stator throat width calculation, result of calculation is rounded up and obtains gate vane channel number, this forward design method considers that the matching of impeller and stator is less, and gate vane channel number major parameter value degrees of freedom is comparatively large, be limited to statistics and personal factor, designing quality can not ensure.Which results in the changeover portion loss of fluid between impeller and flow channel type guide blade comparatively large, the efficiency of pump is declined to some extent, does not meet the requirement that pump is energy-conservation.

Summary of the invention

For the deficiencies in the prior art, object of the present invention is intended to provide a kind of flow channel type guide blade design method, causes to reduce because impeller and stator do not mate the problem that pump energy consumption increases, and improves the efficiency of pump, meets the requirement that pump is energy-conservation.

For achieving the above object, the present invention adopts following technological scheme:

A kind of flow channel type guide blade design method, comprises the following steps:

Step one, try to achieve vane inlet width b by formula (1) ₃,

b ₃＝b ₂+(2～5)mm (1)

In formula, b ₃for vane inlet width, b ₂for impeller outlet width;

Step 2, try to achieve vane inlet laying angle α by formula (2) ₃,

tgα ₃＝(1.1～1.3)tgα ₂(2)

In formula, α ₃for vane inlet laying angle, α ₂for the absolute flow angle of impeller outlet;

Step 3, try to achieve stator base circle diameter (BCD) D by formula (3) ₃,

D ₃＝(1.02～1.05)D ₂(3)

In formula, D ₂for impeller diameter, D ₃for stator base circle diameter (BCD);

Step 4, blade inlet thickness δ ₃value is 3 ~ 7mm;

Step 5, by vane inlet laying angle α ₃, blade inlet thickness δ ₃with stator Base radius R ₃bring formula (4) into, obtain number of blade z and throat width a ₃relation,

In formula, z is the number of blade, α ₃for vane inlet laying angle, a ₃for stator throat width, δ ₃for blade inlet thickness, R ₃for stator Base radius;

Step 6, according to Anderson area ratio principle, the area ratio formula of flow channel type guide blade multistage pump is:

Y＝F ₂/F _d(5)

In formula, Y is area ratio coefficient, F ₂for the discharge area between impeller blade, F _dfor stator throat opening area;

Discharge area F between step 7, impeller blade ₂can be calculated by formula (6)

F ₂＝πD ₂b ₂tgβ ₂(6)

In formula, D ₂for impeller diameter, b ₂for impeller outlet width, β ₂for blade exit laying angle;

Step 8, determine area ratio coefficient Y by formula (7),

Y＝1/(0.036849+0.002310n _s) (7)

In formula, n _sfor the specific speed of pump;

Step 9, because of the known F of flow channel type guide blade throat opening area formula _dwith a ₃with the relation of z,

F _d＝za ₃b ₃(8)

In formula, z is the number of blade, a ₃for stator throat width, b ₃for vane inlet width;

Step 10, the F that formula (6) is determined ₂and the area ratio coefficient Y that formula (7) is determined substitutes in formula (5), thus try to achieve F _d, then the F that will try to achieve _dsubstitute into formula (8), obtain a ₃with the relation of z, owing to also obtaining number of blade z and throat width a in formula (4) ₃relation, obtain two unknown numbers according to formula (4) and formula (9) two solution of equations and draw stator throat width a ₃with number of blade z, after trying to achieve number of blade z, be taken as integer, then substitute in formula (4) and determine a ₃numerical value, finally obtain b ₃, z and a ₃parameters combination.

Beneficial effect of the present invention is:

Compared to prior art, the present invention is on the basis that conventional flow field formula stator designs, and the area ratio principle of application Anderson, to determine vane inlet width b ₃, stator throat width a ₃with stator number z, consider the matching of impeller and stator, which reduce hydraulic loss, improve the efficiency of pump, reach energy-saving and cost-reducing object.

Accompanying drawing explanation

Fig. 1 is the structural representation of stator of the present invention;

Fig. 2 is the schematic side view of Fig. 1;

Fig. 3 is the specific speed n of area ratio coefficient Y and pump _sloose point and line graph.

Embodiment

Below, by reference to the accompanying drawings and embodiment, the present invention is described further:

As shown in Figure 1 to Figure 3, flow channel type guide blade design method of the present invention is mainly used in and ignores when solving the design of existing flow channel type guide blade and the unmatched significance of impeller and cause the problem that pump work efficiency is not high.For this reason, on the basis of conventional flow field formula stator design, the area ratio principle of application Anderson, to determine vane inlet width b ₃, stator throat width a ₃with stator number z.Anderson area ratio principle thinks that impeller outlet area of passage and pump throat area ratio are the main determining factors of the performance parameters such as centrifugal pump lift, flow, air horsepower.The present invention design stator according to the known parameters for the pump housing and blade wheel structure.

This flow channel type guide blade design method comprises the following steps:

Step one, consider vane inlet width b ₃with impeller outlet width b ₂mate, so b ₃span very little, try to achieve vane inlet width b by formula (1) ₃,

b ₃＝b ₂+(2～5)mm (1)

In formula, b ₃for vane inlet width, b ₂impeller outlet width (b ₂being the parameter of impeller, is given value);

Step 2, try to achieve vane inlet laying angle α by formula (2) ₃,

tgα ₃＝(1.1～1.3)tgα ₂(2)

In formula, α ₃for vane inlet laying angle, α ₂for the absolute flow angle (α of impeller outlet ₂being the parameter of impeller, is given value);

Step 3, try to achieve stator base circle diameter (BCD) D by formula (3) ₃,

D ₃＝(1.02～1.05)D ₂(3)

In formula, D ₂for impeller diameter (D ₂being the parameter of impeller, is given value), D ₃for stator base circle diameter (BCD);

Step 4, blade inlet thickness δ ₃value is 3 ~ 7mm;

Step 5, by vane inlet laying angle α ₃, blade inlet thickness δ ₃with stator Base radius R ₃bring formula (4) into, obtain number of blade z and throat width a ₃relation,

In formula, z is the number of blade, α ₃for vane inlet laying angle, a ₃for stator throat width, δ ₃for blade inlet thickness, R ₃for stator Base radius is (due to D ₃tried to achieve by formula (2), R ₃=D ₃/ 2 is also given value);

Step 6, according to Anderson area ratio principle, the area ratio formula of flow channel type guide blade multistage pump is:

Y=F ₂/ F _d=(discharge area between impeller blade)/(stator throat opening area) (5)

In formula, Y is area ratio coefficient, F ₂for the discharge area between impeller blade, F _dfor stator throat opening area;

Particularly, when Anderson area ratio principle is applied to Ordinary Centrifugal Pumps, formula Y=F can be obtained ₂/ F ₁, in formula, Y is area ratio coefficient, F ₂for the discharge area between impeller blade, F ₁for pump throat area; When Anderson area ratio principle is applied to flow channel type guide blade multistage pump, formula Y=F can be obtained ₂/ F _d.

Discharge area F between step 7, impeller blade ₂can be calculated by formula (6)

F ₂＝πD ₂b ₂tgβ ₂(6)

In formula, D ₂for impeller diameter, b ₂for impeller outlet width, β ₂for blade exit laying angle, D ₂, b ₂, β ₂are all parameters of impeller blade, are given value;

Step 8, determine area ratio coefficient Y by formula (7),

Y＝1/(0.036849+0.002310n _s) (7)

In formula, n _sfor the specific speed (n of pump _sbeing the parameter of pump, is given value);

Step 9, because of the known F of flow channel type guide blade throat opening area formula _dwith a ₃with the relation of z,

F _d＝za ₃b ₃(8)

In formula, z is the number of blade, a ₃for stator throat width, b ₃for vane inlet width, (b ₃tried to achieve by formula (1));

Step 10, the F that formula (6) is determined ₂and the area ratio coefficient Y that formula (7) is determined substitutes in formula (5), thus try to achieve F _d, then the F that will try to achieve _dsubstitute into formula (8), obtain a ₃with the relation of z, owing to also obtaining number of blade z and throat width a in formula (4) ₃relation, obtain two unknown numbers according to formula (4) and formula (9) two solution of equations and draw stator throat width a ₃with number of blade z, after trying to achieve number of blade z, be taken as integer, then substitute in formula (4) and determine a ₃numerical value, so just obtain best parameter group (b ₃, z, a ₃).

The present invention is on the basis that conventional flow field formula stator designs, and the area ratio principle of application Anderson, to determine vane inlet width b ₃, stator throat width a ₃with stator number z, consider the matching of impeller and stator, which reduce hydraulic loss, improve the efficiency of pump, reach energy-saving and cost-reducing object.

Further, as shown in Figure 3, in step 9, by the specific speed n of the lower 3 kinds of pattern pumps of sorting-out in statistics different specific speed _swith loose some graph of a relation of the inverse (1/Y) of area ratio coefficient Y, then give n by linear regression and linear fit _swith the manual line of loose point of 1/Y and the regression equation of Y, the regression equation of Y is formula (8).

To one skilled in the art, according to technological scheme described above and design, other various corresponding change and deformation can be made, and all these change and deformation all should belong within the protection domain of the claims in the present invention.

Claims (1)

1. a flow channel type guide blade design method, is characterized in that, comprises the following steps:

Step one, try to achieve vane inlet width b by formula (1) ₃,

b ₃＝b ₂+(2～5)mm (1)

In formula, b ₃for vane inlet width, b ₂for impeller outlet width;

Step 2, try to achieve vane inlet laying angle α by formula (2) ₃,

tgα ₃＝(1.1～1.3)tgα ₂(2)

In formula, α ₃for vane inlet laying angle, α ₂for the absolute flow angle of impeller outlet;

Step 3, try to achieve stator base circle diameter (BCD) D by formula (3) ₃,

D ₃＝(1.02～1.05)D ₂(3)

In formula, D ₂for impeller diameter, D ₃for stator base circle diameter (BCD);

Step 4, blade inlet thickness δ ₃value is 3 ~ 7mm;

Step 5, by vane inlet laying angle α ₃, blade inlet thickness δ ₃with stator Base radius R ₃bring formula (4) into, obtain number of blade z and throat width a ₃relation,

$z=\frac{\mathrm{\π}sin2{\mathrm{\α}}_3}{In\[(a_3+{\mathrm{\δ}}_3)\frac{{\mathrm{cos\α}}_3}{R_3}+1\]}---\left(4\right)$

In formula, z is the number of blade, α ₃for vane inlet laying angle, a ₃for stator throat width, δ ₃for blade inlet thickness, R ₃for stator Base radius;

Step 6, according to Anderson area ratio principle, the area ratio formula of flow channel type guide blade multistage pump is:

Y＝F ₂/F _d(5)

In formula, Y is area ratio coefficient, F ₂for the discharge area between impeller blade, F _dfor stator throat opening area;

Discharge area F between step 7, impeller blade ₂can be calculated by formula (6)

F ₂＝πD ₂b ₂tgβ ₂(6)

In formula, D ₂for impeller diameter, b ₂for impeller outlet width, β ₂for blade exit laying angle;

Step 8, determine area ratio coefficient Y by formula (7),

Y＝1/(0.036849+0.002310n _s) (7)

In formula, n _sfor the specific speed of pump;

Step 9, because of the known F of flow channel type guide blade throat opening area formula _dwith a ₃with the relation of z,

F _d＝za ₃b ₃(8)

In formula, z is the number of blade, a ₃for stator throat width, b ₃for vane inlet width;

Step 10, the F that formula (6) is determined ₂and the area ratio coefficient Y that formula (7) is determined substitutes in formula (5), thus try to achieve F _d, then the F that will try to achieve _dsubstitute into formula (8), obtain a ₃with the relation of z, owing to also obtaining number of blade z and throat width a in formula (4) ₃relation, obtain two unknown numbers according to formula (4) and formula (9) two solution of equations and draw stator throat width a ₃with number of blade z, after trying to achieve number of blade z, be taken as integer, then substitute in formula (4) and determine a ₃numerical value, finally obtain b ₃, z and a ₃parameters combination.