CN101718347A - Design method of multi-orifice sleeve-type flow control valve and sleeve-type flow control valve - Google Patents

Abstract

The invention relates to a design method of a multi-orifice sleeve-type flow control valve and a sleeve-type flow control valve, in particular to design method of a sleeve-type flow control valve and a multi-orifice sleeve-type flow-adjusting valve designed by the design method of a sleeve-type flow control valve. The method comprises the following steps: calculating water head loss; calculating the sectional area of a cylindrical inner sluice of the flow control valve; calculating a resistance coefficient; calculating a corresponding relation between the dimensionless flow coefficient tau of an adjusting valve and the valve opening coefficient y of the adjusting valve; and calculating and confirming the parameters of orifices on the cylindrical inner sluice. The invention dents the characteristic curve of the dimensionless valve flow coefficient tau and the opening coefficient y to form an ideal flow control valve and can simply design the flow control valve to be designed in practice by adjusting the nominal diameter of the cylindrical inner sluice of the flow control valve and the distribution and the sizes of the orifices on the cylindrical inner sluice, thereby lightening the manufacture of the flow control valve by applying the prior process.

Description

Telescopic flow-adjustable valve design method of many spray orifices and telescopic flow-adjustable valve

Technical field

The present invention relates to telescopic flow-adjustable valve design method of a kind of many spray orifices and telescopic flow-adjustable valve, being design method and the equipment that is used for a kind of valve of water delivery engineering, is a kind of design method of telescopic flow-adjustable valve and the telescopic flow-adjustable valve of many spray orifices that uses described design method design.

Background technique

The birth of many spray orifice cover skeleton symbol flow-adjustable valves has had history (Miller, 1969 in 40 years; Burgi, 1977), in water delivery engineering, obtain extensive use at present.Many spray orifice cover skeleton symbol flow-adjustable valves have following advantage: 1. can be under the High Pressure Difference environment, and long-term nothing cavitation erosion operation; 2. can be omnidistance (by standard-sized sheet to complete shut-down) current-regulating voltage-regulating, transfer and flow the precision height, be generally inflow-rate of water turbine ± 0.5%; 3. do not have harmfulness noise and vibration, when being used for clear water, failure-free operation for a long time reaches 30-50 working life; 4. can adopt multiple modes such as electric power, hydraulic pressure to drive.Both can execute-in-place, also can distant place control; 5. energy dissipating, pressure relief ranges are wide, can adapt to the continuous variation of upstream head.Spray orifice on the sleeve of the existing telescopic flow-adjustable valve of many spray orifices is even distribution, and the diameter of all spray orifices is identical.This spray orifice evenly distributes and the dimensionless valve flow coefficient τ and the aperture y characteristic curve of the telescopic flow-adjustable valve that injection diameter is identical are linear, perhaps epirelief.Up-to-date studies show that, centering high head, long distance, large flow pipe road water delivery engineering, there is the problem of water attack process control difficulty in the design of existing flow-adjustable valve characteristic, its reason is when big aperture, flow reduces to change not quite with aperture y's, make the change of flow concentrate on little aperture, cause surge pressure excessive, perhaps the shut-in time is oversize and can't implement.

Summary of the invention

For overcoming the prior art problem, the present invention proposes telescopic flow-adjustable valve design method of a kind of many spray orifices and telescopic flow-adjustable valve, the conscious modification dimensionless of described design method valve flow coefficient τ and aperture y characteristic curve, with this characteristic curve to recessed, form desirable flow-adjustable valve, its characteristic is to make flow with aperture y linear change, and at this moment the hydraulic pressure during throttle down was directly proportional with the shut-in time, in the identical linear shut-in time, the surge pressure that flow-adjustable valve causes raises minimum.It is bigger that hole on the sleeve of the telescopic flow-adjustable valve of specific design is designed to the hole of upper cartridge, and the hole of lower cartridge is less.

The object of the present invention is achieved like this: the design method of the telescopic flow-adjustable valve of a kind of many spray orifices is characterized in that the step of described method is as follows:

The step of calculated water head loss: be used for according to specified criteria: flow-adjustable valve design discharge Q _r, upstream and downstream pond water surface design altitude difference Δ Z, piping design resistance coefficient S passes through formula:

ΔH _r＝ΔZ-SQ _r ²

Loss of head Δ H when calculating the flow-adjustable valve standard-sized sheet _r

Calculate the step of the drum type inner brake sectional area of flow-adjustable valve: be used to select the drum type inner brake nominal diameter D of flow-adjustable valve, and calculate drum type inner brake sectional area A by drum type inner brake nominal diameter D;

Calculate the step of resistance coefficient: be used for by flow-adjustable valve design discharge Q _r, the loss of head Δ H during the flow-adjustable valve standard-sized sheet _r, drum type inner brake sectional area A and formula:

${\mathrm{\ζ}}_r=\frac{2g{A}^2\mathrm{\Δ}{H}_r}{{Q_r}^2}$

Valve resistance coefficient ζ when calculating the flow-adjustable valve standard-sized sheet _r

Corresponding relation and calculate the step of determining the spray orifice parameter on the drum type inner brake between the immeasurable firm flow coefficient τ that calculates modulating valve and the valve opening coefficient y of modulating valve: be used to set up immeasurable firm flow coefficient τ and valve opening coefficient y corresponding relation or approximate corresponding relation curve, and calculate the size of the spray orifice on definite drum type inner brake and spray orifice distributed parameter along circumferential and axial according to described relation curve.

A kind of telescopic flow-adjustable valve of many spray orifices according to the said method design, comprise: the valve body that is provided with water outlet, the middle part of described valve body is equipped with valve seat, drum type inner brake with a plurality of spray orifices is installed on the described valve seat, the top of inner brake connects valve cage, described valve cage connects water intake, transmission and power plant also are installed on the described valve cage, the injection diameter of described drum type inner brake is different with the variation of position, the injection diameter of the drum type inner brake first half is bigger, and the injection diameter of Lower Half is less.

The beneficial effect that the present invention produces is: by with dimensionless valve flow coefficient τ and aperture y characteristic curve, this characteristic curve to recessed, is formed desirable flow-adjustable valve.Can simply realize that by the nominal diameter of adjusting flow-adjustable valve drum type inner brake, the distribution and the size of the spray orifice on the drum type inner brake flow-adjustable valve of manufacturing carry out to(for) the existing technology of application does not increase too many difficulty during the specific design flow-adjustable valve.The diameter of spray orifice can achieve the goal about only changing on the drum type inner brake in actual production.The flow-adjustable valve that designs according to the method for the invention adapts to the Water Hammer Control of growing distance, large flow pipe road water-carriage system, and effect is obvious.

Description of drawings

The invention will be further described below in conjunction with drawings and Examples.

Fig. 1 is the water delivery engineering schematic representation;

Fig. 2 is the dimensionless valve flow coefficient τ and the aperture y characteristic curve of traditional flow-adjustable valve;

Fig. 3 is the dimensionless valve flow coefficient τ and the aperture y characteristic curve of the desirable flow-adjustable valve of the embodiment of the invention one described method design;

Fig. 4 is the dimensionless valve flow coefficient τ and the aperture y characteristic curve of the flow-adjustable valve of the embodiment of the invention three described method designs;

Fig. 5 is the embodiment of the invention four described flow-adjustable valve structural representations.

Embodiment

Embodiment one:

The water level of water delivery engineering and the position of flow-adjustable valve are as shown in Figure 1.Z wherein ₁And Z ₂Be respectively the level of tail water of the upper pool elevation and the flow-adjustable valve of flow-adjustable valve 1.Flow-adjustable valve is imported and exported loss of head and be can be described as

$\mathrm{\ΔH}=\mathrm{\ζ}\frac{V^2}{2g}---\left(1\right)$

In the formula: the loss of head of Δ H-flow-adjustable valve; V-is by the flow rate of water flow of flow-adjustable valve, ζ-valve resistance coefficient, g-gravity accleration.

Formula (1) can be rewritten as

$\mathrm{\ΔH}=\mathrm{\Δ}{H}_r\frac{\left|q\right|q}{{\mathrm{\τ}}^2}---\left(2\right)$

In the formula: Δ H _r-flow-adjustable valve standard-sized sheet, i.e. the loss of head of the flow-adjustable valve during y=1.0, wherein subscript r represents the flow-adjustable valve standard-sized sheet; Q=Q/Q _r $\mathrm{\τ}=\sqrt{{\mathrm{\ζ}}_r/\mathrm{\ζ}}$ Dimensionless valve flow coefficient.

Flow-adjustable valve producer usually provides ζ-y discrete data to represent the flow-adjustable valve characteristic, or employing formula (2) relation can get the relation curve of dimensionless valve flow coefficient τ shown in Figure 2 and valve opening coefficient y.

From Fig. 2 as seen, traditional dimensionless valve flow coefficient τ and valve opening coefficient y characteristic curve are linear, perhaps epirelief, and this helps allowing accurate flow control in the whole stroke of valve, but is unfavorable for the Water Hammer Control of long pipeline.

Present embodiment is the design method of the telescopic flow-adjustable valve of a kind of many spray orifices.Present embodiment obtains the formula of desirable modulating valve τ and y by dimensionless flow coefficient τ is combined with valve opening coefficient y and pepeline characteristic, and then according to the actual conditions needs, design adapts to many spray orifice cover skeleton symbol flow-adjustable valves of Water Hammer Control.

In order to realize above-mentioned target, at first set up analytical model:

The loss of head of valve can be described as

$\mathrm{\ΔH}=\mathrm{\ζ}\frac{Q^2}{2g{A}^2}---\left(3\right)$

In the formula: the loss of head of Δ H-flow-adjustable valve, Q-flow-adjustable valve flow, A-flow-adjustable valve sectional area, ζ-valve resistance coefficient, g-gravity accleration.

Formula (3) can be rewritten as

$\mathrm{\ΔH}=\frac{\mathrm{\Δ}{H}_r}{Q_r^2}\frac{Q^2}{{\mathrm{\τ}}^2}---\left(4\right)$

In the formula: Δ H _r-flow-adjustable valve standard-sized sheet, promptly during y=1.0, i.e. the loss of head of the flow-adjustable valve during valve wide open, wherein subscript r represents the flow-adjustable valve standard-sized sheet; Q=Q/Q _r $\mathrm{\τ}=\sqrt{{\mathrm{\ζ}}_r/\mathrm{\ζ}}$ The dimensionless flow coefficient.

As shown in Figure 1, Bernoulli's energy equation of pond, pipeline upstream and lower reservoir is

z ₁＝z ₂+ΔH+SQ ² (5)

In the formula: Z ₁Pond ,-upstream water level elevation; Z ₂Pond ,-downstream water level elevation; S-pipeline resistance coefficient.The loss of head of the 3rd expression in formula (5) the right pipeline.

Formula (4) substitution formula (5) is got

$\mathrm{\Δz}=\frac{\mathrm{\Δ}{H}_r}{Q_r^2}\frac{Q^2}{{\mathrm{\τ}}^2}+S{Q}^2---\left(6\right)$

In the formula: Δ z=z ₁-z ₂

Because τ=1 and Q=Q during valve wide open _r, can get from formula (6)

$S=\frac{\mathrm{\Δz}-\mathrm{\Δ}{H}_r}{Q_r^2}---\left(7\right)$

If flow Q is during with valve opening y linear change, promptly

Q＝Q _ry (8)

At this moment flow-adjustable valve will have best hydraulic performance, and the flow-adjustable valve that satisfies this condition just is called desirable flow-adjustable valve.

Formula (7) and formula (8) are concerned that substitution formula (6) can get

$\mathrm{\Δz}=\mathrm{\Δ}{H}_r\frac{y^2}{{\mathrm{\τ}}^2}+(\mathrm{\Δz}-\mathrm{\Δ}{H}_r)y^2$

Put in order

$\mathrm{\τ}=y\sqrt{\frac{\mathrm{\Δ}{H}_r}{\mathrm{\Δz}-(\mathrm{\Δz}-\mathrm{\Δ}{H}_r)y^2}}---\left(9\right)$

Formula (9) is exactly the relation of desirable flow-adjustable valve τ and y.In other words, as long as satisfy formula (9) condition, flow is just with the valve opening linear change.Fig. 3 shows the relation curve of desirable flow-adjustable valve dimensionless flow coefficient τ and valve opening y.Obviously, desirable flow-adjustable valve characteristic curve is a concave shape.

By $\mathrm{\τ}=\sqrt{{\mathrm{\ζ}}_r/\mathrm{\ζ}}$ Can get

$\mathrm{\ζ}=\frac{{\mathrm{\ζ}}_r}{\mathrm{\Δ}{H}_r}\frac{\mathrm{\Δz}-(\mathrm{\Δz}-\mathrm{\Δ}{H}_r)y^2}{y^2}---\left(10\right)$

Formula (10) is exactly the valve resistance coefficient ζ of desirable flow-adjustable valve and the relation of y.

According to this theory, present embodiment is as follows to the step of the design method of the design proposition of modulating valve:

The step of calculated water head loss: be used for according to specified criteria: flow-adjustable valve design discharge Q _r, upstream and downstream pond water surface design altitude difference Δ Z, piping design resistance coefficient S passes through formula:

ΔH _r＝ΔZ-SQ _r ²

Loss of head Δ H when calculating the flow-adjustable valve standard-sized sheet _r

Calculate the step of the drum type inner brake sectional area of flow-adjustable valve: be used to select the drum type inner brake nominal diameter D of flow-adjustable valve, and calculate drum type inner brake sectional area A by drum type inner brake nominal diameter D.

Calculate the step of resistance coefficient: be used for by flow-adjustable valve design discharge Q _r, the loss of head Δ H during the flow-adjustable valve standard-sized sheet _r, drum type inner brake sectional area A and formula:

$\mathrm{\ΔH}=\mathrm{\ζ}\frac{Q^2}{2g{A}^2}$

Valve resistance coefficient ζ when calculating the flow-adjustable valve standard-sized sheet _r

Corresponding relation and calculate the step of determining the spray orifice parameter on the drum type inner brake between the immeasurable firm flow coefficient τ that calculates modulating valve and the valve opening coefficient y of modulating valve: be used to set up immeasurable firm flow coefficient τ and valve opening coefficient y corresponding relation or approximate corresponding relation curve, and calculate the size of the spray orifice on definite drum type inner brake and spray orifice distributed parameter along circumferential and axial according to described relation curve.

Calculate the mode of determining the spray orifice parameter on the drum type inner brake according to corresponding relation between the valve opening coefficient y of the immeasurable firm flow coefficient τ of modulating valve and modulating valve, can promptly determine according to desirable method by formula (10):

$\mathrm{\ζ}=\frac{{\mathrm{\ζ}}_r}{\mathrm{\Δ}{H}_r}\frac{\mathrm{\Δz}-(\mathrm{\Δz}-\mathrm{\Δ}{H}_r)y^2}{y^2}---\left(10\right)$

Bring a series of values of y between 0 and 1 into a series of ζ values that formula (10) is fallen into a trap and got it right and answer.How much that selectes numerical value between 0 and 1 determines that by permissible accuracy the required precision height is then selected more numerical value, otherwise then few.For example: with 1/10th serves as to choose numerical value at interval then to be: 0.1,0.2 ..., or one of more accurate use percentage is at interval, perhaps coarse use 1/5th at interval or the like.Pass through formula then: $\mathrm{\τ}=\sqrt{{\mathrm{\ζ}}_r/\mathrm{\ζ}}$ The value that calculates τ finally obtains the relation curve between y and the τ.Obtain to calculate the spray orifice size determined on the drum type inner brake according to this relation curve again and along the regularity of distribution of circumferential and axial.Calculate the spray orifice size on the drum type inner brake and are a kind of common computational methods according to the relation curve between y and the τ along the distribution of circumferential and axial, can in many documents, find (Burgi, P.H. " Hydraulic Tests andDevelopment of Multijet Sleeve Valves.”Bur.Reclam.Rep.RECERC77-14.Div?ofGen?Res.December?1977.)。

Make that desirable flow-adjustable valve is technical can be accomplished, but may make that flow-adjustable valve nominal diameter D is excessive, the flow-adjustable valve cost is too high.In this case, adopt following design method: the value of between 0 and 1, choosing 1 to 3 y, calculate corresponding τ value by formula (9), make a broken line type y and a τ relation curve that is similar to the relation curve between desirable y and the τ according to these several τ values, again by this broken line type y and τ relation curve, calculate and determine the big or small of spray orifice on the valve body and along the regularity of distribution of circumferential and axial.(special-purpose software is arranged).How much being determined by precision of selected element if select a point, then obtains one two sections broken line as y=0.5, if select two points, is exactly a tri linear, and so on.

Embodiment two:

Present embodiment is embodiment one improvement, be embodiment one about the corresponding relation between the valve opening coefficient y of the immeasurable firm flow coefficient τ that calculates modulating valve and modulating valve and the refinement of calculating the step of the spray orifice parameter on definite drum type inner brake.The step of the spray orifice parameter on the drum type inner brake is determined in corresponding relation and calculating between the immeasurable firm flow coefficient τ of the described calculating modulating valve of present embodiment and the valve opening coefficient y of modulating valve:

With Δ Z, Δ H _r, a plurality of numerical value of equaling between the 0-1 of A and y bring formula into:

$\mathrm{\ζ}=\frac{{\mathrm{\ζ}}_r}{\mathrm{\Δ}{H}_r}\frac{\mathrm{\Δz}-(\mathrm{\Δz}-\mathrm{\Δ}{H}_r)y^2}{y^2}$ Obtain a plurality of and valve opening coefficient y value corresponding valve resistance coefficient ζ value;

By $\mathrm{\τ}=\sqrt{{\mathrm{\ζ}}_r/\mathrm{\ζ}}$ Obtain a plurality of immeasurable firm flow coefficient τ values corresponding, form corresponding relation curve between the valve opening coefficient y of immeasurable firm flow coefficient τ and modulating valve with valve opening coefficient y value;

Determine spray orifice parameter on the drum type inner brake according to corresponding relation curve calculation between the valve opening coefficient y of immeasurable firm flow coefficient τ and modulating valve.

Present embodiment is a kind of design of desirable flow-adjustable valve.

Embodiment three:

Present embodiment is embodiment one improvement, be embodiment one about the corresponding relation between the valve opening coefficient y of the immeasurable firm flow coefficient τ that calculates modulating valve and modulating valve and the refinement of calculating the step of the spray orifice parameter on definite drum type inner brake.The step of the spray orifice parameter on the drum type inner brake is determined in corresponding relation and calculating between the immeasurable firm flow coefficient τ of the described calculating modulating valve of present embodiment and the valve opening coefficient y of modulating valve:

With parameter Δ Z, Δ H _r, y=0.5 brings formula into:

$\mathrm{\τ}=y\sqrt{\frac{\mathrm{\Δ}{H}_r}{\mathrm{\Δz}-(\mathrm{\Δz}-\mathrm{\Δ}{H}_r)y^2}}$

Calculate the value τ of τ when y=0.5 _0.5

Corresponding relation curve between the valve opening coefficient y of immeasurable firm flow coefficient τ and modulating valve is made as two sections, as shown in Figure 4:

τ＝τ _0.5y，0≤y≤0.5

τ＝τ _0.5+2(1-τ _0.5)(y-0.5)，0.5＜y≤1

According to $\mathrm{\τ}=\sqrt{{\mathrm{\ζ}}_r/\mathrm{\ζ}},$ Promptly $\mathrm{\ζ}=\frac{{\mathrm{\ζ}}_r}{{\mathrm{\τ}}^2},$ Calculate the value of different opening y corresponding valve resistance coefficient ζ;

According to the parameter of valve resistance coefficient ζ and valve opening coefficient y, calculate to determine the size of spray orifice on the valve body and along the regularity of distribution of circumferential and axial.Generally speaking, in 0≤y≤0.5 interval, spray orifice is big or small identical on the valve body; In 0.5≤y≤1 interval, the size of spray orifice is also identical on the valve body.

Present embodiment is the design of two broken lines between the valve opening coefficient y of a kind of immeasurable firm flow coefficient τ and modulating valve, adapt to industrial production, existing flow-adjustable valve production technology need not change substantially, only changes on drum type size that inner brake punches that some are just passable.

Embodiment four:

A kind of telescopic flow-adjustable valve of many spray orifices according to the described method design of the foregoing description, as scheme shown in Figure 5, comprise: the valve body 6 that is provided with water outlet, the middle part of valve body is equipped with valve seat 7, drum type inner brake 8 with a plurality of spray orifices is installed on the valve seat, the top of inner brake connects valve cage 4, valve cage connects water intake 2, transmission and power plant 3 also are installed on the valve cage, the injection diameter of drum type inner brake is difference with the variation of its position on the drum type inner brake, the injection diameter of the drum type inner brake first half is bigger, and the injection diameter of Lower Half is less.

Present embodiment adopted is the flow-adjustable valve of the design design of relation curve between the valve opening coefficient y of a kind of immeasurable firm flow coefficient τ of two broken lines and modulating valve, the injection diameter of the so-called drum type inner brake first half is bigger, the injection diameter of Lower Half is less refer at the first half of drum type inner brake different with the diameter of the spray orifice of Lower Half, the spray orifice of the first half is bigger, and the spray orifice of Lower Half is less.Initial stage water at the flow-adjustable valve opening process can only spray from less spray orifice like this, and at this moment because the spray orifice of opening is less, and the pressure of single spray orifice water is bigger, though the diameter of spray orifice is less, flow is not little.When the later stage of drum type inner brake opening process, the draining of most spray orifice, the hydraulic pressure of single spray orifice reduces, and at this moment uses the big spray orifice can enlargement discharge.According to desirable state, the drum type inner brake is to open from lower to upper, and the injection diameter that is distributed on the drum type inner brake should strengthen from lower to upper gradually.Otherwise if the drum type inner brake is to open from top to bottom, the injection diameter that is distributed on the drum type inner brake should strengthen from top to bottom gradually.In a word, the spray orifice of opening should be less earlier, and the spray orifice that open the back should be bigger.But in the manufacture process of actual flow-adjustable valve, the spray orifice of too many diameter is processed too complicated, and is unfavorable to the manufacturing process engineering.The injection diameter that only changes the drum type inner brake first half and Lower Half has been enough to the effect that reaches good, the diameter of spray orifice on the change drum type inner brake that therefore needn't be too much.

It should be noted that at last, below only unrestricted in order to technological scheme of the present invention to be described, although the present invention is had been described in detail with reference to the preferred arrangement scheme, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technological scheme of the present invention (carrying out etc.), and not break away from the spirit and scope of technical solution of the present invention such as other recessed modes of relation curve between conversion, τ and the y of formula.

Claims (4)

1. the design method of the telescopic flow-adjustable valve of spray orifice more than a kind is characterized in that the step of described method is as follows:

The step of calculated water head loss: be used for according to specified criteria: flow-adjustable valve design discharge Q _r, upstream and downstream pond water surface design altitude difference Δ Z, piping design resistance coefficient S passes through formula:

ΔH _r＝ΔZ-SQ _r ²

Loss of head Δ H when calculating the flow-adjustable valve standard-sized sheet _r

Calculate the step of the drum type inner brake sectional area of flow-adjustable valve: be used to select the drum type inner brake nominal diameter D of flow-adjustable valve, and calculate drum type inner brake sectional area A by drum type inner brake nominal diameter D;

Calculate the step of resistance coefficient: be used for by flow-adjustable valve design discharge Q _r, the loss of head Δ H during the flow-adjustable valve standard-sized sheet _r, drum type inner brake sectional area A and formula:

${\mathrm{\ζ}}_r=\frac{2g{A}^2\mathrm{\Δ}{H}_r}{{Q_r}^2}$

Valve resistance coefficient ζ when calculating the flow-adjustable valve standard-sized sheet _r

Corresponding relation between the immeasurable firm flow coefficient τ of calculating modulating valve and the valve opening coefficient y of modulating valve, and calculate to determine the step of the spray orifice parameter on the drum type inner brake: be used to set up immeasurable firm flow coefficient τ and valve opening coefficient y corresponding relation or approximate corresponding relation curve, and calculate the size of determining the spray orifice on the drum type inner brake and spray orifice distributed parameter along circumferential and axial according to described relation curve.

2. method according to claim 1 is characterized in that between the valve opening coefficient y of the immeasurable firm flow coefficient τ of described calculating modulating valve and modulating valve corresponding relation and calculates the step of determining the spray orifice parameter on the drum type inner brake:

With Δ Z, Δ H _r, a plurality of numerical value of equaling between the 0-1 of A and y bring formula into:

$\mathrm{\ζ}=\frac{{\mathrm{\ζ}}_r}{\mathrm{\Δ}{H}_r}\frac{\mathrm{\Δz}-(\mathrm{\Δz}-\mathrm{\Δ}{H}_r)y^2}{y^2}$ Obtain a plurality of and valve opening coefficient y value corresponding valve resistance coefficient ζ value;

By $\mathrm{\τ}=\sqrt{{\mathrm{\ζ}}_r/\mathrm{\ζ}}$ Obtain a plurality of immeasurable firm flow coefficient τ values corresponding, form corresponding relation curve between the valve opening coefficient y of immeasurable firm flow coefficient τ and modulating valve with valve opening coefficient y value;

Determine spray orifice parameter on the drum type inner brake according to corresponding relation curve calculation between the valve opening coefficient y of immeasurable firm flow coefficient τ and modulating valve.

3. method according to claim 1 is characterized in that between the valve opening coefficient y of the immeasurable firm flow coefficient τ of described calculating modulating valve and modulating valve corresponding relation and calculates the step of determining the spray orifice parameter on the drum type inner brake:

With parameter Δ Z, Δ H _r, y=0.5 brings formula into:

$\mathrm{\τ}=y\sqrt{\frac{\mathrm{\Δ}{H}_r}{\mathrm{\Δz}-(\mathrm{\Δz}-\mathrm{\Δ}{H}_r)y^2}}$

Calculate the value τ of τ when y=0.5 _0.5

Corresponding relation curve between the valve opening coefficient y of immeasurable firm flow coefficient τ and modulating valve is made as two sections:

τ＝τ _0.5y，0≤y≤0.5

τ＝τ _0.5+2(1-τ _0.5)(y-0.5)，0.5＜y≤1

According to $\mathrm{\τ}=\sqrt{{\mathrm{\ζ}}_r/\mathrm{\ζ}}$ , promptly $\mathrm{\ζ}=\frac{{\mathrm{\ζ}}_r}{{\mathrm{\τ}}^2}$ , the value of calculating different opening y corresponding valve resistance coefficient ζ;

According to the parameter of valve resistance coefficient ζ and valve opening coefficient y, calculate to determine the size of spray orifice on the valve body and along the regularity of distribution of circumferential and axial.

4. telescopic flow-adjustable valve of many spray orifices according to the design of the described method of claim 3, comprise: the valve body that is provided with water outlet, the middle part of described valve body is equipped with valve seat, drum type inner brake with a plurality of spray orifices is installed on the described valve seat, the top of inner brake connects valve cage, described valve cage connects water intake, transmission and power plant also are installed on the described valve cage, it is characterized in that, the injection diameter of described drum type inner brake is different with the variation of position, the injection diameter of the drum type inner brake first half is bigger, and the injection diameter of Lower Half is less.

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