CN2086816U - Combined energy-saving unit combating cavitation erosion - Google Patents

Abstract

The utility model discloses a combined energy saving device with cavitation erosion resistance which aims at overcoming the problems that induced wheel can increase the cavitation erosion resistance performance and delivery lift of a pump, but the performance can not be further improved with the limitation of the pump. Thus, the combined energy saving device with cavitation erosion resistance which comprises a passive impeller, a pump, a ventilator, a hydraulic turbine, and a screw is provided. The diameter of the passive impeller can increase according to need; thus, the cavitation erosion resistance performance and the delivery lift both increase according to need. Thus, the purpose of cavitation erosion resistance performance improvement, delivery lift increase, efficiency increase, and power consumption saving is achieved.

Description

Combined energy-saving unit combating cavitation erosion

The utility model relates to a kind of fast V of advancing _AFluid act on the passive impeller combined unit that the anti-cavitation performance of main wheel and thrust are increased.

Common way is:

1, an inducer is set in the centrifugal wheel front, be used for improving the cavitation performance of pump, its mechanism is exactly that inducer is regarded as an auxiliary suction booster, it can be worked under certain level of cavitation, and can flow through the needed flow of pump, increase enough pressure heads to fluid simultaneously, cavitation does not take place when making centrifugal wheel work.So the cavitation performance of entire pump just can decide by the cavitation performance of inducer (referring to: " pump technology " 80.2.P3 page or leaf).

2, super cavitation pump is a common centrifugal pump in essence, but installs a supercavitation level on the extension of its main shaft additional.This supercavitation level provides low cavitation allowance ability for pump, and produces enough pressure heads (lift) in case produce cavitation in centrifugal impeller; Centrifugal impeller then provides most lift increment.Being created in hole on the supercavitation blade extended to the downstream and reaches one to two blade chord length approximately before it is vanished; Before liquid entered centrifugal wheel, the hole is fine vanished.Because the relation of blade angle, the axial distance between these two impellers is very short.But super cavitation pump is a kind of low lift impeller in itself, so during higher if desired lift, just must additional first-stage centrifugal pump (referring to: " pump technology " 76.1.P67 page or leaf).

3, equidirectional prewhirling can make the axial flow lift of pump increase, and efficient improves.As shown in Figure 1.(referring to: " pump technology " 82.3.P5 page or leaf).

The model utility purpose:

Can obviously increase efficient and lift though Zhong Jinzhi goes out axial flow pump, the volute flume is bulky, and the pressure loss is big, is difficult to random installation; Though its anti-cavitation performance of inducer is good, can further bring into play and improve by driving wheel restriction cavitation-resistance; The supercavitation wheel also is can further improve by driving wheel restriction cavitation-resistance.Though prewhirl in order to overcome above-mentioned one of the impeller inlet that can give, but the contradiction that performance own can not further be brought into play, the spy provides this passive impeller and pump, ventilator, water turbine, propeller cavitation associating anti-cavitation energy saving device, and it can increase efficient, lift and anti-cavitation performance.

The content of invention:

1, brief description of drawings:

1) as Fig. 1: the Test Drawing that Zhong Jinzhi goes out.Wherein, (1) Zhong Jinzhi goes out; (2) elbow advances directly.

2) as Fig. 2: passive impeller and water pump associating anti-cavitation energy saving device figure.Wherein, (1) passive impeller; (2) pipe; (3) pump; (4) propeller boss of passive impeller; (5) aerofoil profile supports.

3) as Fig. 3: passive impeller and pump combined unit matching properties figure.Wherein, (1) passive impeller; (2) pipe; (3) pump.

2, the detailed content of invention:

(1) basic principle: referring to Fig. 2.

Passive impeller (1) is put the front of the runner (3) of what pump, the axle of passive impeller (1) is bound up by bearing and propeller boss (4), propeller boss (4) pipe (2) inwall good by support member (5) and certain geometrical shape is consolidated, and forms passive impeller (1) and pump (3) and puts combined energy-saving unit combating cavitation erosion in the what pipe (2).

The blade back of the runner (3) of the blade back of passive impeller (1) and pump is put in the same way.The β of passive impeller (1) _i, α _A, α _TDeng a timing, at the fast V that advances of pump (3) _AUnder the effect, according to (V _A)/(2 π rn)=tg β _i. (1-a _T)/(1+a _A) with rotation speed n ₁Rotate.By u _A1=2 α _A1V _ACan try to achieve the axial induced velocity u of passive impeller (1) _A1Runner (3) under the main frame effect with rotation speed n ₂Rotation is by u _A2=2 α _A2V _ACan try to achieve the axial induced velocity u of driving wheel (3) _A2Therefore, the axial induced velocity of the runner (3) of pump is u in the associating energy saving device _A=u _A1+ u _A2So the total head of pump (3) is:

H＝ (P)/(γ) ＝ (A ₁)/(g) （V _A＋ (u _A1)/2 ）u _A＝ (A ₁)/(g) （V _A＋V _A＋ (u _A1)/2 ）（u _A1＋u _A2）

The efficient of pump (3) is changed into:

$\mathrm{\η}=\frac{{\mathrm{\ρ}}^2{A_1}^2{(V_A+\frac{u_{A1}}{2})}^2(u_{A1}+u_{A2})}{102N}$

At main frame with rotation speed n ₂When making runner (3) rotation, current are with V _AEnter pipeline (2).And passive impeller (1) advances fast V at current _AUnder the effect, by (V _A)/(2 π rn)=Const knows that it is with rotation speed n ₁Rotation.Because the unusual part of passive impeller (1) is: can install in any pipeline in driving wheel (3) front (2) cross section, so the diameter of this impeller (1) can change arbitrarily.Now suppose the radius r of passive impeller (1) ₁Radius r for driving wheel (3) ₂Two times, i.e. r ₁=2r ₂Know by the flow conservation law:

Q ₁＝Q ₂＝Const

Or

πr ₁ ²V _A1＝πr ₂ ²V _A2

With r ₁=2r ₂Substitution gets:

4r ₂ ²V _A1＝r ₂ ²V _A2

Old friend: V _A1=1/4 V _A2, and substitution:

(V _A)/(2πrn) ＝tgβ _i(1-a _T)/(1+a _A) ＝Const

:

$\frac{V_{A1}}{2\mathrm{\π}{r}_1{n}_1}=\frac{\frac{1}{4}{V}_{A2}}{2\mathrm{\π}\left({2r}_2\right)n_1}=\mathrm{Const}$

So:

n ₁＝ (n2)/8

By U ₁=r ₁ω ₁=2 π r ₁n ₁=2 π (2r ₂) ((n ₂)/8)=1/4 (2 π r ₂n ₂)=(U ₂)/4 are known, the blade tip linear velocity U of passive impeller (1) ₁Obviously reduce the rotation speed n of passive impeller (1) ₁Also can increase.

By inlet flow rate coefficient φ _1t=240Q/ π ²ND ³ _1t(1-v ²) know that when the Q flow was constant, the hub diameter ratio was at D ₁Increasing diameter added-time v=d ₁/ D ₁Reduce, and D ₁, n ₁Increase, so φ _1tReduce.

The substitution cavitation is counted K=2 φ ² _1t/ (1-2 φ ² _1t) know K ₁Value reduces.

With K ₁, n ₁, D ₁, v ₁Substitution cavitation specific speed:

S _s＝C ₁［Q／nD ³ _1t] 1/2 ／｛C ₂（1＋K）［Q／nD ³ _1t（1－v ²）］ ²＋K｝ 3/4

Know S _sValue increases, so the anti-cavitation performance of passive impeller (1) obviously increases.

In like manner, the runner of pump (3) is under the effect of prewhirling of passive impeller (1), and rotating speed is by n ₂Increase to n ₂+ n ₁', all the other parameters are all constant, so S _sValue increases, and the runner of pump (3) is that the driving wheel anti-cavitation performance increases.Along with passive impeller (1) rotation speed n ₁Increase n ₂Increase thereupon.

The basic principle of Here it is this associating anti-cavitation energy saving device.

2) calculating of implementation step:

(1) the resistance coefficient ζ of driven wheel (1) blade ₁But verification certificate wing formula data determines, at current to advance fast V _AWhen flowing through impeller (1).

(2) (i) the resistance coefficient ζ of the body of revolution propeller boss (4) of driven wheel (1) ₄Can try to achieve by practical fluid resistance handbook.

The (ii) fixing resistance coefficient ζ of the aerofoil profile supporting element (5) of impeller (1) body of revolution propeller boss (4) and pipeline (2) wall ₅Can try to achieve by practical fluid resistance handbook.

(3) at (P)/(D), (A _E)/(A _D), Z is certain, at X=0.75 place: δ, φ, α ₀, α ₀' known, then calculate α with following table _A, α _T:

［1］α ⁰［11］C _L′＝（α _g／10.4）K _CL

［2］β _i ⁰＝φ ⁰－α ⁰［12］tgβ _i

［3］b ［13］tg ²β _i

［4］2π ［14］λ _i＝Xtgβ _i

［5］r ［15］K＝f（X，λ _i）

［6］s＝zb／2πr ［16］（1＋tg ²β _i） 1/2

［7］K _α0＝f（s，β _i） ［17］ (a _T)/(1-a _T) ＝ (s)/4 . (C _L′)/(K) （1＋tg ²β _i） 1/2

［8］△α _g＝K _α0α ₀′ ［18］α _T

［9］α _g＝α＋α ₀－△α _g［19］ (a _A)/(1+a _A) ＝ (［17］)/(tg ²β _i)

［10］K _CL＝f（s，β _i） ［20］α _A

By α _A=(u _A)/(2V _A) must different α ⁰Under induced velocity u _A1:

u _A1＝2α _A1V _A

By P=ρ (V _A+ (uA)/2) u _AGet different α ⁰Under thrust (pressure) P ₁:

P ₁＝ρ（V _A＋ (u _A1)/2 ）u _A1

By Q=V _AA ₁:

Q＝πr ₁ ²V _A

The P of impeller (1) thus draws---the Q performance diagram.

When (4) current are flowed through pipeline (2), its resistance coefficient ζ ₂:

ζ ₂＝f (L)/(D) ＋∑ζ

In the formula:

F---friction factor, available f=0.020+ 0.0005/ (D) tries to achieve; Or look into handbook and try to achieve;

L---pipeline length;

D---bore;

∑ ζ---coefficient of partial resistance can be looked into handbook and get;

(5) total losses head:

$P=\mathrm{\γH}=\mathrm{\γ}{h}_f=\frac{[f\frac{L}{D}+\mathrm{\Σ\ζ}+{\mathrm{\ζ}}_4+{\mathrm{\Σ\ζ}}_5+{\mathrm{\Σ\ζ}}_1]}{2g}\·\frac{16{\mathrm{\γQ}}^2}{{\left({\mathrm{\πD}}^2\right)}_2}$

Pipeline (2) characteristic curve P thus draws---Q figure.

(6) the characteristic curve P of pump (3)---Q figure is known.

(7) as shown in Figure 3, be depicted as pipeline (2) characteristic curve of same scale and passive impeller (1) characteristic curve and move and be incorporated into being painted on the neutralization of same coordinate, revolution is fixed and is painted on P down---P of the pump in the mark of Building Q---, and the Q characteristic line gets on, and with passive impeller (1) and pump (3) P---the Q characteristic line is superposition mutually, the characteristic line of the P behind the superposition---Q characteristic line and pipeline (2) intersects, and its intersection point (operation point) is just determined this pump and impeller at this ducted pressure P and flow Q.

(8) useful horsepower of pump:

N ₃＝ ((P ₁+P ₃))/102

(9) efficient of pump:

η＝（P ₁＋P ₃）Q／102N

Surplus associating energy saving device calculates in like manner.Because all according to (V _A)/(2 π rn)=Const.

Further broadening of the present invention:

Obviously, may make many improvement and variation according to the content of narrating above.Therefore can fully understand and what infer is that within our claims scope, the present invention can be implemented with the mode that is different from clearly narration.For example, can with the pipe of certain geometrical shape they be bound up, also can use multistage passive impeller pressurization with ducted propeller similar conduit impeller and pump, ventilator, water turbine, propeller cavitation.The two-wheeled counter-rotating is with racemization.

Claims (2)

1, a kind of associating anti-cavitation energy saving device, this device has a runner (3), passive impeller (1), the pipe of handy certain geometrical shape (2) is put what wherein with them, it is characterized in that passive impeller (1) puts the front of what runner (3), the axle of passive impeller (1) is bound up by bearing and propeller boss (4), and propeller boss (4) pipe (2) inwall good by supporting element (5) and certain geometrical shape is consolidated, and passive impeller (1) rotates freely under the fluid effect.

2,, it is characterized in that the blade back of passive impeller (1) and the blade back of runner (3) put in the same way as the described device of claim (1).