CN104005983B - A kind of higher specific speed axial-flow pump impeller three operating point method for designing - Google Patents

Abstract

The invention provides a kind of higher specific speed axial-flow pump impeller three operating point method for designing, this impeller is applicable to the occasions such as field irrigation, power plant's cooling circulation and city water.It is characterized in that when designing axial-flow pump impeller, to connect by relational expression between geometric parameter and the performance parameter of the operating point for design of pump, low flow rate condition point and big flow rate working conditions point of impeller, make pump all can meet design requirement in the performance parameter of above three operating point, designed by the performance parameter of three operating points and realize the control to pump performance curvilinear characteristic and adjustment, meet, to obtain, the axial-flow pump performance curve that design requires.The design performance requirement of multiple operating point can not only be met with the higher specific speed axial-flow pump of present invention design, also there is efficiency district high, efficient width and stable feature.

Description

A kind of higher specific speed axial-flow pump impeller three operating point method for designing

Technical field

Patent of the present invention relates to a kind of higher specific speed axial-flow pump impeller three operating point method for designing, specifically, relates to one Plant and be applicable to meet the high-efficiency axial-flow pump impeller method for designing that the design of multiple operating point requires.

Background technology

At present, axial-flow pump impeller design generally individually use either simplex condition design method of points, the determination of its impeller geometric parameter and Calculate the performance parameter being all based on operating point for design.Along with the increase of axial-flow pump specific speed, its performance curve presents an allusion quotation The saddle-shape change of type, the head curve of axial-flow pump first drops and rises afterwards, is consequently formed the operation conditions of instability.Meanwhile, at big stream In the case of amount, the most easily there is significantly reduced phenomenon, performance curve dramatic decrease in axial flow pump lift, efficiency curve, thus lead There is the hydraulic efficiency feature that district is narrow and stable operation scope is little low, efficient in the higher specific speed axial-flow pump causing conventional design.At height In the actual moving process of specific speed axial-flow pump, the actual operating mode point of pump assembly and operating point for design are the most misaligned, in fact The flow of border running operating point typically can change between low flow rate condition point and big flow rate working conditions point.Therefore, for height than turning For the axial-flow pump of speed, in order to improve the efficient sector width of hydraulic performance curve, improve impeller internal flowing and operation stability, Tackle its performance curve between low flow rate condition point to big flow rate working conditions point and carry out certain control and optimization.

No. 200810235506.5 patents of the patented technology first having " the multi-state point design method of centrifugal pump impeller ", mainly A kind of multi-state method for designing proposed for middle low specific-speed centrifugal pump, the method is by impeller outer circular diameter and width two Individual parameter carries out multi-state design.No. 201010520561.6 patents of patented technology " a kind of centrifugal pump multi-state water based on CFD Power optimization method " it is by mean of initial hydraulic model data base, iterating and calculating by CFD numerical simulation technology, Progressively matching is with the method obtaining ideal performance curve.201010520494.8 " a kind of centrifugal pump based on loss is many for number patent Operating mode hydraulic optimization method " it is equally based on initial hydraulic loss formula and external characteristics result of the test, soft by design Iterating of part, the method finally converging to ideal curve.Existing patented technology yet suffers from following two problem: 1. existing The relevant patented technology having is all the design method for centrifugal pump impeller about radial blade structure, there is presently no and is suitable for high ratio The multi-state design method of points of performance of axial flow pump impeller of pump；2. prior art is not pointed out to make with the performance parameter of how many operating points The most suitable for design parameter, simply propose a scope substantially, and too much or very few design parameter the most easily causes The inefficacy of design process and design result inaccurate.

Summary of the invention

In order to overcome the deficiency of existing higher specific speed axial-flow pump impeller method for designing, the invention provides a kind of new height ratio Performance of axial flow pump impeller of pump three operating point method for designing, uses the axial-flow pump of present invention design can not only meet operating point for design Hydraulic performance requirement, additionally it is possible to impeller is controlled at the hydraulic performance of low flow rate condition point and big flow rate working conditions point.Use The airfoil geometry parameter of impeller and three stream interfaces of radial direction can be adjusted by the axial-flow pump impeller of present invention design, is finally reached The purpose that the predicted performance curves of axial-flow pump and the performance curve of requirement essentially coincide, and effectively increase the efficient district of axial-flow pump Width and stable operation scope.

The technical scheme is that

When designing impeller, according to the flow under axial-flow pump operating point for design, low flow rate condition point and big flow rate working conditions point, Lift parameter Q_opt、H_opt、Q₁、H₁、Q₂、H₂Requirement, design corresponding axial-flow pump impeller geometric parameter values.Its method be by The geometric parameter of axial-flow pump impeller has contacted with the performance parameter of its operating point for design, low flow rate condition point and big flow rate working conditions point Come so that between physical dimension parameter and the performance parameter of above three operating point of impeller, be suitable for the pass of following equation System:

$D=\frac{{(Q_1^{1.5}+Q_{opt}^{15}+Q_2^{1.5})}^{0.33}}{n{\left({\mathrm{tan\β}}_b\right)}^{0.5}{Q}_{opt}^{0.66}}\sqrt{\frac{H_1^2+H_{opt}^2+H_2^2}{1-14.1{n_s}^{-0.53}}}$

D_j=(1.86-0.22In (n_s))D

$R_a=\frac{1+k_a}{2}D-\frac{D_j}{2}$

$R_b=\frac{1+k_b}{2}D-\frac{D_j}{2}$

$R_c=\frac{1+k_c}{2}D-\frac{D_j}{2}$

${\mathrm{tan\β}}_a=16.93\sqrt{\frac{0.76\sqrt{2{\mathrm{gH}}_1}}{1+z}{\left(\frac{n_s}{100}\right)}^{1.65}}\frac{(H_1-H_2)}{{\left(Q_{opt}{n}^2\right)}^{2/3}}$

${\mathrm{tan\β}}_b=16.93\sqrt{\frac{0.76\sqrt{2{\mathrm{gH}}_{opt}}}{1+z}{\left(\frac{n_s}{100}\right)}^{1.65}}\frac{(H_1-H_{opt})}{{\left(Q_{opt}{n}^2\right)}^{2/3}}$

${\mathrm{tan\β}}_c=16.93\sqrt{\frac{0.76\sqrt{2{\mathrm{gH}}_2}}{1+z}{\left(\frac{n_s}{100}\right)}^{1.65}}\frac{(H_{opt}-H_2)}{{\left(Q_{opt}{n}^2\right)}^{2/3}}$

In formula: D impeller outer diameter, rice；N wheel speed, rev/min；

Q_optOperating point for design flow, cube meter per second；H_optOperating point for design lift, rice；

Q₁Low flow rate condition point flow, cube meter per second；H₁Low flow rate condition point lift, rice；

Q₂Big flow rate working conditions point flow, cube meter per second；H₂Big flow rate working conditions point lift, rice；

D_jImpeller hub diameter, rice；n_sImpeller specific speed；

R_aThe radius of stream interface A, rice；R_bThe radius of stream interface B, rice；

R_cThe radius of stream interface C, rice；k_aCorrection factor, k_a=0.85～0.90；

k_bCorrection factor, k_b=0.45～0.50；k_cCorrection factor, k_c=0.1～0.15；

β_aThe aerofoil profile laying angle of stream interface A, degree；β_bThe aerofoil profile laying angle of stream interface B, degree；

β_cThe aerofoil profile laying angle of stream interface C, degree；G acceleration of gravity, rice/square second；

Z impeller blade number, sheet.

In above-mentioned relation formula, the shape facilities such as the length of impeller stream interface aerofoil profile, thickness are not claimed, therefore exist Can select freely during design, NACA aviation aerofoil profile or the circular arc airfoil of application more maturation is selected in general recommendations, has It is beneficial to die modeling and the casting processing of impeller.Stream interface A refers to around radius of central line R_aThe face of cylinder determined.Stream interface B refers to Around radius of central line R_bThe face of cylinder determined.Stream interface C refers to around radius of central line R_cThe face of cylinder determined.

Knowable to above-mentioned method for designing, the radial position of three stream interfaces determines the shape of impeller blade, in order to obtain conjunction The stream interface radial dimension of reason, should consider the aerofoil profile size characteristic on stream interface.Accordingly, it is determined that the method for stream interface radius is: The relation of applicable below equation between radius and its aerofoil profile length of radially distributed tri-stream interfaces of A, B, C:

$\frac{2{\mathrm{\πR}}_a}{l_{a}z}=1.39~1.67$

$\frac{R_b}{l_{b}z}=0.91\frac{R_a}{l_{a}z}$

$\frac{R_c}{l_{c}z}=0.82\frac{R_a}{l_{a}z}$

In formula: R_aThe radius of stream interface A, rice；R_bThe radius of stream interface B, rice；

R_cThe radius of stream interface C, rice；l_aThe aerofoil profile length of stream interface A, rice；

l_bThe aerofoil profile length of stream interface B, rice；l_cThe aerofoil profile length of stream interface C, rice；

Z impeller blade number, sheet.

In above-mentioned method for designing, the low flow rate condition point of impeller and the flow parameter of big flow rate working conditions point select have one Fixed restriction scope, flow selects more than design limit scope can produce impact to the predicted performance curves of impeller.Determine rill The method of amount operating point and big flow rate working conditions point selection scope is: low flow rate condition point and the flow Q of big flow rate working conditions point₁、Q₂With The flow Q of its operating point for design_optBetween should be suitable for the relation of below equation:

$\frac{Q_1}{Q_{opt}}=0.65~0.85$

$\frac{Q_2}{Q_{opt}}=1.15~1.35$

Size according to axial-flow pump specific speed determines impeller blade number z, and it is generally 3-5 sheet, when impeller specific speed is bigger Time, select the less number of blade.

The invention has the beneficial effects as follows: use the higher specific speed axial-flow pump impeller of the method design can not only meet design The performance parameter requirement of operating point, additionally it is possible to meet low flow rate condition point and the requirement of big flow rate working conditions point, use this impeller Axial-flow pump has efficiency district high, efficient width and the feature operated steadily.

The present invention tries out through user, and product using effect is good, and the hydraulic characteristic of this impeller is steady, and efficient district width, non- Operational reliability under design conditions effectively improves.

Accompanying drawing explanation

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

Fig. 2 is the paddle wheel plane figure of same embodiment；

Fig. 3 is the aerofoil profile figure of the impeller stream interface A of same embodiment；

Fig. 4 is the aerofoil profile figure of the impeller stream interface B of same embodiment；

Fig. 5 is the aerofoil profile figure of the impeller stream interface C of same embodiment；

In figure: 1 impeller outer diameter D, 2 impeller hub diameter D_j, 3 impeller blades, 4 impeller hubs, 5 stream interface A Radius R_a, the radius R of 6 stream interface B_b, the radius R of 7 stream interface C_c, the aerofoil profile of 8 stream interface A lays angle beta_a, the wing of 9 stream interface A Type length l_a, the aerofoil profile of 10 stream interface B lays angle beta_b, aerofoil profile length l of 11 stream interface B_b, the aerofoil profile laying angle of 12 stream interface C β_c, aerofoil profile length l of 13 stream interface C_c。

Detailed description of the invention

Fig. 1 to Fig. 5 combination defines impeller shape and the physical dimension of this embodiment.This is the height of a kind of open architecture Specific speed axial-flow pump impeller, the outer rim of impeller blade (3) is circular arc type, is evenly distributed on impeller hub (4), impeller blade (3) shape is determined by stream interface A, B, C and aerofoil profile thereof.Impeller blade (3) is generally 3-5 sheet, when impeller specific speed is bigger, and choosing Select the less number of blade.The present invention determines impeller outer diameter D (1), impeller hub diameter D by following relational expression_j(2)、 The radius R of stream interface A_a(5), the radius R of stream interface B_b(6), the radius R of stream interface C_c(7), the aerofoil profile of stream interface A lays angle beta_a(8), stream interface The aerofoil profile of B lays angle beta_bAnd the aerofoil profile of stream interface C lays angle beta (10)_c(12)。

$D=\frac{{(Q_1^{1.5}+Q_{opt}^{15}+Q_2^{1.5})}^{0.33}}{n{\left({\mathrm{tan\β}}_b\right)}^{0.5}{Q}_{opt}^{0.66}}\sqrt{\frac{H_1^2+H_{opt}^2+H_2^2}{1-14.1{n_s}^{-0.53}}}$

D_j=(1.86-0.22In (n_s))D

$R_a=\frac{1+k_a}{2}D-\frac{D_j}{2}$

$R_b=\frac{1+k_b}{2}D-\frac{D_j}{2}$

$R_c=\frac{1+k_c}{2}D-\frac{D_j}{2}$

${\mathrm{tan\β}}_a=16.93\sqrt{\frac{0.76\sqrt{2{\mathrm{gH}}_1}}{1+z}{\left(\frac{n_s}{100}\right)}^{1.65}}\frac{(H_1-H_2)}{{\left(Q_{opt}{n}^2\right)}^{2/3}}$

${\mathrm{tan\β}}_b=16.93\sqrt{\frac{0.76\sqrt{2{\mathrm{gH}}_{opt}}}{1+z}{\left(\frac{n_s}{100}\right)}^{1.65}}\frac{(H_1-H_{opt})}{{\left(Q_{opt}{n}^2\right)}^{2/3}}$

${\mathrm{tan\β}}_c=16.93\sqrt{\frac{0.76\sqrt{2{\mathrm{gH}}_2}}{1+z}{\left(\frac{n_s}{100}\right)}^{1.65}}\frac{(H_{opt}-H_2)}{{\left(Q_{opt}{n}^2\right)}^{2/3}}$

The design of impeller stream interface aerofoil profile can select freely, it is proposed that selects NACA aviation aerofoil profile or circular arc airfoil, Be conducive to die modeling and the casting processing of impeller.

In the drawings, the radius (5) of stream interface A, B, C, (6), (7) are designed, along footpath according to respective aerofoil profile size characteristic The relation of applicable below equation between radius and its aerofoil profile length of tri-stream interfaces of A, B, C of distribution:

$\frac{2{\mathrm{\πR}}_a}{l_{a}z}=1.39~1.67$

$\frac{R_b}{l_{b}z}=0.91\frac{R_a}{l_{a}z}$

$\frac{R_c}{l_{c}z}=0.82\frac{R_a}{l_{a}z}$

During design impeller, low flow rate condition point and the flow Q of big flow rate working conditions point₁、Q₂With its operating point for design Flow Q_optBetween should be suitable for the relation of below equation:

$\frac{Q_1}{Q_{opt}}=0.65~0.85$

$\frac{Q_2}{Q_{opt}}=1.15~1.35$

The selection of impeller blade number z is relevant with its specific speed, and it is generally 3-5 sheet, when impeller specific speed is bigger, selects The less number of blade.

So higher specific speed axial-flow pump impeller of design just can meet operating point for design, low flow rate condition point simultaneously and flow greatly The performance parameter requirement of amount operating point, and by controlling the performance parameter value of different operating point, it is achieved to axial flow pump performance curve Adjustment and optimization so that the predicted performance curves of axial-flow pump essentially coincides with the performance curve of requirement, meets performance curve Design requirement.

Claims (4)

1. a higher specific speed axial-flow pump impeller three operating point method for designing, according to axial-flow pump in operating point for design, low discharge work Flow under condition point and big flow rate working conditions point, lift parameter Q_opt、H_opt、Q₁、H₁、Q₂、H₂Design requirement, design high than turning The geometric parameter of speed axial-flow pump impeller, it is characterised in that: by the geometric parameter of axial-flow pump impeller and its operating point for design, low discharge The performance parameter of operating point and big flow rate working conditions point connects so that axial-flow pump performance curve meets above three operating mode simultaneously The performance parameter requirement of point, is i.e. suitable for following several between physical dimension parameter and the performance parameter of above three operating point of impeller The relation of individual equation:

$D=\frac{{(Q_1^{1.5}+Q_{opt}^{1.5}+Q_2^{1.5})}^{0.33}}{n{\left({\mathrm{tan\β}}_b\right)}^{0.5}{Q}_{opt}^{0.66}}\sqrt{\frac{H_1^2+H_{opt}^2+H_2^2}{1-14.1n_s^{-0.53}}}$

D_j=(1.86-0.22In (n_s))D

$R_a=\frac{1+k_a}{2}D-\frac{D_j}{2}$

$R_b=\frac{1+k_b}{2}D-\frac{D_j}{2}$

$R_c=\frac{1+k_c}{2}D-\frac{D_j}{2}$

${\mathrm{tan\β}}_a=16.93\sqrt{\frac{0.76\sqrt{2{\mathrm{gH}}_1}}{1+z}{\left(\frac{n_s}{100}\right)}^{1.65}}\frac{(H_1-H_2)}{{\left(Q_{opt}{n}^2\right)}^{2/3}}$

${\mathrm{tan\β}}_b=16.93\sqrt{\frac{0.76\sqrt{2{\mathrm{gH}}_{opt}}}{1+z}{\left(\frac{n_s}{100}\right)}^{1.65}}\frac{(H_1-H_{opt})}{{\left(Q_{opt}{n}^2\right)}^{2/3}}$

${\mathrm{tan\β}}_c=16.93\sqrt{\frac{0.76\sqrt{2{\mathrm{gH}}_2}}{1+z}{\left(\frac{n_s}{100}\right)}^{1.65}}\frac{(H_{opt}-H_2)}{{\left(Q_{opt}{n}^2\right)}^{2/3}}$

In formula: D is impeller outer diameter, rice；N is wheel speed, rev/min；

Q_optIt is operating point for design flow, cube meter per second；H_optIt is operating point for design lift, rice；

Q₁It is low flow rate condition point flow, cube meter per second；H₁It is low flow rate condition point lift, rice；

Q₂It is big flow rate working conditions point flow, cube meter per second；H₂It is big flow rate working conditions point lift, rice；

D_jIt is impeller hub diameter, rice；n_sIt it is impeller specific speed；

R_aIt is the radius of stream interface A, rice；R_bIt is the radius of stream interface B, rice；

R_cIt is the radius of stream interface C, rice；k_aIt is correction factor, k_a=0.85～0.90；

k_bIt is correction factor, k_b=0.45～0.50；k_cIt is correction factor, k_c=0.1～0.15；

β_aIt is the aerofoil profile laying angle of stream interface A, degree；β_bIt is the aerofoil profile laying angle of stream interface B, degree；

β_cIt is the aerofoil profile laying angle of stream interface C, degree；G is acceleration of gravity, rice/square second；

Z is impeller blade number, sheet.

2. a kind of higher specific speed axial-flow pump impeller three operating point method for designing as claimed in claim 1, is characterized in that: impeller leaf The shape of sheet is mainly determined by the aerofoil profile of radially distributed tri-stream interfaces of A, B, C, and the radius of three stream interfaces is long with its aerofoil profile The relation of applicable below equation between degree:

$\frac{2{\mathrm{\πR}}_a}{l_{a}z}=1.39~1.67$

$\frac{R_b}{l_{b}z}=0.91\frac{R_a}{l_{a}z}$

$\frac{R_c}{l_{c}z}=0.82\frac{R_a}{l_{a}z}$

In formula: R_aIt is the radius of stream interface A, rice；R_bIt is the radius of stream interface B, rice；

R_cIt is the radius of stream interface C, rice；l_aIt is the aerofoil profile length of stream interface A, rice；

l_bIt is the aerofoil profile length of stream interface B, rice；l_cIt is the aerofoil profile length of stream interface C, rice；

Z is impeller blade number, sheet.

3. a kind of higher specific speed axial-flow pump impeller three operating point method for designing as claimed in claim 1, is characterized in that: impeller The flow of low flow rate condition point and big flow rate working conditions point is respectively Q₁、Q₂, itself and the flow Q of operating point for design_optBetween be suitable for The relation of lower equation:

$\frac{Q_1}{Q_{opt}}=0.65~0.85$

$\frac{Q_2}{Q_{\mathrm{opt}}}=1.15~1.35.$

4. a kind of higher specific speed axial-flow pump impeller three operating point method for designing as claimed in claim 1, is characterized in that: impeller leaf Sheet number z is 3-5 sheet.