阅读说明：本技术 一种高速泵用开式叶轮结构 (A kind of express pump unshrouded impeller structure ) 是由 李晓俊 刘遥遥 陈晖� 杨宝锋 朱祖超 于 2019-08-27 设计创作，主要内容包括：本发明涉及一种工程机械。目的是提供一种开式叶轮结构的改进,该叶轮应具有减弱或消除驼峰曲线、平衡轴向力,减轻排挤现象、降低进口流速、减小泵的水力损失的特点。技术方案是：一种高速泵用开式叶轮结构,包括轮毂、与轮毂连为一体且以轮毂轴线为中心放射状布置的若干叶片承载板以及一一布置在叶片承载板上的若干叶片；其特征在于：每个叶片承载板由靠近轮毂且倾斜于轮毂轴线的倾斜段与垂直于轮毂轴线的直线段组成；所述叶片的一部分穿嵌在叶片承载板倾斜段上预设的通槽中并且在叶轮背面露出部分叶片形成辅助叶片,另一部分作为正面叶片固定在叶片承载板直线段的正面且与直线段平面垂直。(The present invention relates to a kind of engineering machinery.Purpose is to provide a kind of improvement of unshrouded impeller structure, which should have decrease or eliminate camel-back curve, balancing axial thrust, mitigates exclusion phenomenon, reduces inlet velocity, reduces the characteristics of hydraulic loss of pump.Technical solution is: a kind of express pump unshrouded impeller structure, including wheel hub, several blades for being linked together and being arranged in using hub axis as several blade loading plates of center radial arrangement and one by one on blade loading plate with wheel hub；It is characterized by: each blade loading plate is by close to wheel hub and favouring the tilting section of hub axis and the straightway perpendicular to hub axis forms；A part of the blade wears in preset through slot on blade loading plate tilting section and forms auxiliary blade in wheel backface exposed portion blade, and another part is fixed on the front of blade loading plate straightway and vertical with straightway plane as positive blade.)

1. a kind of express pump unshrouded impeller structure, including wheel hub (2), it is linked together with wheel hub and is put centered on hub axis Several blades (5) penetrating several blade loading plates (1) of shape arrangement and being arranged on blade loading plate one by one；Its feature exists In: each blade loading plate by close to wheel hub and favour the tilting section of hub axis with perpendicular to the straightway group of hub axis At；A part of the blade is worn in preset through slot on blade loading plate tilting section and in wheel backface exposed portion Blade forms auxiliary blade (3), and another part is fixed on front and and the straight line of blade loading plate straightway as positive blade Section plane is vertical；The tilting section of the blade loading plate and the radical length ratio of straightway are 1:1.1-1.2；

The partial blade in blade loading plate through slot is worn, is opened when also being stretched from the middle part in length of blade direction toward wheel hub direction Beginning distortion and the diameter line for deviateing wheel hub, so that the diameter line with wheel hub forms import placement angle It can be by following formula It obtains:

In formula: Q-- flow

F₁-- flow channel of axial plane discharge section area

η_v-- the volumetric efficiency of pump

D₁-- impeller inlet diameter

δ₁-- the thickness of blade

λ₁-- the angle of axial plane transversal and meridian streamline is taken as 75o here

The lobe numbers of Z-- pump；

β₁-- vane inlet laying angle；

M-- empirical coefficient, general value are 0.055~0.08

Wherein: F₁=2 π R_Ch

In formula: R_C-- the radius of curvature of curve.

2. express pump according to claim 1 unshrouded impeller structure, it is characterised in that the positive blade width b₁With it is auxiliary Help width of blade b₂Ratio be 2:0.8-1.5；

Wherein:

In formula: h-- blade overall width.

Technical field

The present invention relates to a kind of engineering machinery, and in particular to a kind of express pump unshrouded impeller structure.

Background technique

Representative of the centrifugal pump as field of hydraulic machinery, there is important role in the industrial production, but in centrifugal pump Design, manufacture, production, always there are some the problem of being difficult to avoid that in operational process.

(1) camel-back curve generated in centrifugal pump operational process, the reason is that when flow is more than or less than design discharge, liquid stream Direction is inconsistent with direction blade, leads to the actual performance curve deviation theory curve of pump.When at small flow, impact loss and Whirlpool loss is bigger than normal, less than normal along journey friction loss, more unfavorable to the stability of performance curve, easily generation hump；Express pump Performance becomes apparent.The performance of the generation pump of hump generates very big negative effect, it is necessary to eliminate or weaken hump.For This, is usually designed to symmetrical spiral case at present in engineering；And such method is more apparent the disadvantage is that when pump works in big flow area When, lift is affected, and working efficiency reduces；It is then that diffusion is installed in pump case there are also some methods for eliminating express pump hump Device, this is conducive to weaken hump phenomenon, but this method is very high to the installation accuracy requirement of diffuser, and manufacture processing is all compared It is difficult.

(2) axial force generated in centrifugal pump operational process, the pressure for unshrouded impeller, on rear side of blade loading plate Greater than front side pressure, the axial force on front side of a biggish direction is thus generated.When impeller does work to liquid, though in impeller outlet Place, liquid momentum axial direction has acted on the dynamical reaction for being directed toward rear side, however this dynamical reaction cannot balance pressure difference generation Axial force, therefore, it is necessary to which him is taken to carry out balancing axial thrust in the method.For express pump, in order to eliminate and weaken cavitation, induction Wheel is widely used at impeller inlet, and the axial force that the presence of inducer generates pump at work further increases.For The design of the structures such as balance hole, balancing frame is usually taken in axial force problem at present；Though it is effective, since very big flow-disturbing acts on, Increase loss.And the blade of express pump is relatively thin, and balance hole is arranged on blade and is not suitable for.The method of selection addition back blade is then It will increase cavity gap after impeller.

Summary of the invention

The purpose of the present invention is overcoming the shortcomings of above-mentioned background technique, a kind of improvement of unshrouded impeller structure, the leaf are provided Wheel should have decrease or eliminate camel-back curve, balancing axial thrust, the waterpower for mitigating exclusion phenomenon, reducing inlet velocity, reducing pump The characteristics of loss.

This blade wheel structure adopts the following technical scheme that

A kind of express pump unshrouded impeller structure, including wheel hub, be linked together with wheel hub and put centered on hub axis Several blades penetrating several blade loading plates of shape arrangement and being arranged on blade loading plate one by one；

It is characterized by: each blade loading plate by close to wheel hub and favour the tilting section of hub axis with perpendicular to wheel The straightway of hub axle line forms；A part of the blade wear in preset through slot on blade loading plate tilting section and Wheel backface exposed portion blade forms auxiliary blade, and another part is fixed on blade loading plate straightway as positive blade It is positive and vertical with straightway plane；The tilting section of the blade loading plate and the radical length ratio of straightway are 1:1.1- 1.2。

The partial blade in blade loading plate through slot is worn, is also stretched from the middle part in length of blade direction toward wheel hub direction When start to distort and deviate the diameter line of wheel hub, so that forming import with the diameter line of wheel hub places angle It can be by following Formula obtains:

In formula: Q-- flow

F₁-- flow channel of axial plane discharge section area

η_v-- the volumetric efficiency of pump

D₁-- impeller inlet diameter

δ₁-- the thickness of blade

λ₁-- the angle of axial plane transversal and meridian streamline is taken as 75 ° here

The lobe numbers of Z-- pump；

β₁-- vane inlet laying angle；

M-- empirical coefficient, general value are 0.055~0.08

Wherein: F₁=2 π R_Ch

In formula: R_C-- the radius of curvature (as shown in Figure 7) of curve；

Q、η_v、β₁It can be chosen from design manual.

The positive blade width b₁With auxiliary blade width b₂Ratio be 2:0.8 to 2:1；

Wherein:

In formula: h-- blade overall width.

The beneficial effects of the present invention are: blade carries out distortion processing, widen vane inlet runner after increasing high incidence, arranges It squeezes phenomenon to mitigate, runner becomes more gentle, thus reduces inlet velocity, reduces the hydraulic loss of pump；Designed is auxiliary It helps blade that can also do work to wheel backface side liquid, pushes the speed to be thrown away, to reduce wheel backface side liquid Pressure balances axial force well, reduces except camel-back curve.

Detailed description of the invention

Fig. 1 is the schematic perspective view of the embodiment of the present invention.

Fig. 2 is the structure schematic diagram of the embodiment of the present invention.

Fig. 3 is the overlook direction cross-sectional view of the embodiment of the present invention.

Fig. 4 is the cross-sectional view of blade loading plate in Fig. 3.

Fig. 5 is the positive structure schematic of the embodiment of the present invention.

Fig. 6 is the shaft section structural schematic diagram of the embodiment of the present invention.

Fig. 7 is the Analysis of Axial schematic diagram of the embodiment of the present invention.

Wherein: 1, blade loading plate；2, wheel hub；3, auxiliary blade；4, balance hole (balance bore dia is d)；5, blade.

Specific embodiment

Illustrated embodiment with reference to the accompanying drawing, the present invention is described in further detail.

1, express pump of the present invention is as depicted in figs. 1 and 2 with unshrouded impeller specific embodiment, the quick runner Blade no longer takes straight blades completely, but carries out distortion processing in import fragment position, and certain entrance angle is arranged

It can be obtained by following formula:

In formula: Q-- flow (is determined) by design requirement

F₁-- flow channel of axial plane discharge section area (is determined) by design requirement

η_v-- the volumetric efficiency (being determined by design requirement) of pump

D₁-- impeller inlet diameter

δ₁-- the thickness of blade

λ₁-- the angle of axial plane transversal and meridian streamline is taken as 75 ° here

The lobe numbers of Z-- pump；

β₁-- vane inlet laying angle can be chosen from design manual；

M-- empirical coefficient, general value are 0.055~0.08

Calculate F₁When, the reduced mechanical model of selection is as follows:

F₁=2 π R_Ch

In formula:

R_C-- the radius of curvature (as shown in Figure 6) of runner boundary curve；(being determined by design requirement)

Blade is carried out distortion processing by the present invention, it is therefore intended that is widened vane inlet runner after increasing high incidence, is squeezed Phenomenon mitigates, and runner becomes more gentle, thus reduces inlet velocity, reduces the hydraulic loss of pump.

Local losses formula are as follows:

In formula: H_f-- local losses head

ζ -- loss coefficient

W-- import peripheral speed.

From the above local losses formula: local losses head is mainly square related with inlet velocity, therefore reduces Inlet velocity is the feasible solution for reducing hydraulic loss, and lesser high incidence is in addition taken to be also beneficial to weaken cavitation.

2, the present embodiment is changed (as shown in Figure 4) blade construction, and a part in blade 5 is worn to be carried embedded in blade On plate 1 and expose in wheel backface to form auxiliary blade 3, another part is fixed on blade loading plate as positive blade The front of straightway and vertical with straightway plane.Positive blade width b₁Account for 2/3rds of blade overall width h, positive blade Width and auxiliary blade width b₂Ratio be 2:0.8-1.5.Do so is to be done using auxiliary blade to wheel backface side liquid Function is pushed the speed to be thrown away, to reduce the pressure of wheel backface side liquid, plays good balance to axial force Effect.

Its specific Calculation and Analysis of Force is as follows:

Liquid is in elevated pressures P when high speed pump work_HIt is lower to enter impeller, and in lower pressure P_LLower outflow impeller.Blade is held Fluid pressure suffered by support plate two sides is unequal, and the structure of unshrouded impeller two sides is also asymmetric, these factors to produce finger It is extremely disadvantageous to pump work to the axial force of outlet.

Act on the pressure of loading plate back side are as follows:

Act on the pressure on front side of loading plate are as follows:

Then two sides pressure difference are as follows:

Due to P_H> P_L, so Δ P is positive value, it is directed toward front side (as shown in Figure 7).

The axial force for acting on loading plate back side can be acquired by above formula:

Act on the axial force on front side of loading plate are as follows:

In addition, the dynamical reaction that inducer generates are as follows:

F_i=ρ g π D_tH_i

In formula: F_r-- loading plate back side axial force

F_l-- axial force on front side of loading plate

F_i-- the dynamical reaction that inducer generates

R₂-- impeller outlet radius

R_h-- impeller hub radius

R_m-- impeller inlet radius

R_A-- the distance at balance hole center to hub centre

The density of ρ -- fluid

G-- acceleration of gravity

H_p-- impeller outlet gesture lift

ω -- impeller angular velocity of rotation

D_t-- induction vane tip diameter

H_i-- inducer inlet head

H_m-- mechanical seal chamber hydrostatic head

The resultant force of generation is then are as follows: F=F_r-F_l-F_i

It, then can be by the pressure of blade loading plate back side by the calculation formula of axial force it is found that axial force to be made is balanced Power reduces, in conjunction with Bernoulli equation,It needs the speed of blade loading plate back side Increase, after blade is integrally through blade loading plate, blade loading plate back side auxiliary blade outstanding can be to blade loading plate The acting of back side liquid, increases its speed, so that pressure reduces, in addition also the partially liq of back side can be enable to throw away, There is good effect for balancing axial thrust, while the design of this auxiliary blade is compared to traditional back blade design side Formula, back side cavity gap are able to diminution largely.

It is assumed that pumped (conveying) medium is water, density 998.2kg/m³, when not designed using auxiliary blade, by aforementioned public affairs Formula, two sides pressure difference are as follows:

And it may be assumed that P_H1=150000Pa, P_L=100000Pa

It when being designed using auxiliary blade, does work to liquid, it is assumed that the outlet linear velocity that liquid obtains is 5m/s, then rear side pressure Power:

Then:

As can be seen from the above equation, blade loading plate back side liquid is only made to obtain relatively small muzzle velocity, Bian Keping The axial force of weighing apparatus 30% can also balance 20% or more axial direction if it is considered that the dynamical reaction of the inducer of impeller inlet acts on Power.Therefore such method has relatively good axial force balance effect.

Since express pump provided by the invention unshrouded impeller design structure is directed to the camel-back curve and axial direction that impeller occurs Power problem provides a kind of design scheme different from the past, it may have good effect.The embodiment is of the invention excellent The embodiment of choosing, but present invention is not limited to the embodiments described above, without departing from the essence of the present invention, this Field technical staff's any obvious improvements, substitutions or variations that can be made all belongs to the scope of protection of the present invention.