CN104443335A - Rectification assembly for pump water-jet propeller - Google Patents

Abstract

The invention discloses a rectification assembly for a pump water-jet propeller. The rectification assembly is installed on the downstream of an impeller of the pump water-jet propeller and the upstream of a spraying nozzle or is integrally cast along with the spraying nozzle and a shell outside of the impeller of the pump water-jet propeller. The rectification assembly is formed by integrally casting or welding an inner shell, an outer shell, a separation sleeve and a rib plate, wherein the separation sleeve is an annular shell with a wing-shaped section and located between the inner shell and the outer shell. The annular shell with the wing-shaped section is additionally arranged between the inner shell and the outer shell and divides a runner on the downstream of the impeller into two annular runners, the flow speed of the outlets of the two annular runners are required to be identical in design, the flow speed difference of the downstream of the impeller of the pump water-jet propeller can be adjusted to reduce the internal flow loss of the pump water-jet propeller, and the propelling force of the pump water-jet propeller under the same input power is improved. By means of the rectification assembly for the pump water-jet propeller, the core component of the whole pump water-jet propeller is easy to machine and higher in efficiency and power density.

Description

A kind of pump waterjet propulsor rectification part

Technical field

The present invention relates to a kind of flow passage components for marine pump hydraulic efficiency jet propulsion system, be specifically related to a kind of pump waterjet propulsor rectification part.

Background technology

Pump waterjet propulsor is a kind of novel propelling unit being applicable to high-performance ship, and higher specific speed axial wheel is the principal mode of its impeller.As an important hydraulic part of pump waterjet propulsor, the design of rectification part is associated with Impeller Design.The design theory of current axial wheel mainly contains three kinds: the arc method based on airfoil theory, the lift method based on cascade theory and the streamline method based on unitary design theory.Wherein streamline method adopts a kind of many methods in recent years, and in specific design, this method is divided into again free vortex method and forced vortex method, and the lift that two kinds of methods obtain and velocity flow profile are as shown in Figure 1.Under normal circumstances, the design objective of axial-flow pump requires in all radial location, and the pace of change that the change stagnation pressure with axial location increases (or reduction) is identical, and therefore stagnation pressure does not change in the radial direction, namely free vortex design method.

Specific to the impeller of pump waterjet propulsor, usual requirement is higher specific speed (low lift) impeller, therefore the circumferential components exporting absolute velocitye is very little, in fact no longer there is for the cascade type rectification part (blower inlet casing) in general irrigation and drainage axial-flow pump the effect of transformation of energy, and due to the rectifying section of pump waterjet propulsor be shrink, general blower inlet casing also can increase its contraction losses due to exclusion effect further, and therefore traditional cascade type rectification part is not suitable for the requirement of pump waterjet propulsor.

On the other hand, although its outlet lift of the aforementioned axial wheel obtained according to free vortex method and flow rate on axial surface even in the radial direction, but compare with forced vortex method, it is larger at the blade angle of hub side that free vortex design obtains blade, the blade angle of wheel rim side is less, and whole blade twist is very large.Moreover, identical with wheel hub at wheel rim place according to the lift that free vortex method obtains, the advantage that wheel rim acting ability is strong could not be utilized completely.That is, compared with forced vortex method, its power density is less than normal.The axial wheel distortion that obtains of forced vortex method is little conversely speaking, power density is high, more meets efficient design requirement.But its deficiency is outlet, and flow rate on axial surface is uneven in the radial direction, therefore need the rectification part developing a kind of axial wheel obtained for the design of forced vortex method.

Summary of the invention

Goal of the invention: in order to overcome the deficiencies in the prior art, the invention provides a kind of pump waterjet propulsor rectification part, for adjusting the flow velocity difference in pump waterjet propulsor impeller downstream, to reduce the internal flow loss of pump waterjet propulsor, improve the thrust of pump waterjet propulsor under identical horsepower input.

Technical scheme: for achieving the above object, pump waterjet propulsor rectification part of the present invention, this rectification part is arranged on the downstream of pump waterjet propulsor impeller, the upstream of nozzle, or form with the housing integrally casting of nozzle and pump waterjet propulsor impeller outer, this rectification part comprises inner casing, shell, point spacer and gusset, the annular casing of described point of spacer to be a section be aerofoil profile, divide spacer between inner casing and shell, described gusset is in axial plane, vertical with inner casing, shell and point spacer.

Pump waterjet propulsor rectification part of the present invention, not containing blade cascade, is made up of by casting or being welded as a whole inner casing, shell, point spacer and gusset.

The axial plane cross section of described point of spacer is the aerofoil profile section meeting hydrodynamic characteristics, and annular and separation cover forms two annular overcurrent runners respectively with inner casing and shell, the lower exit flow velocity of two annular overcurrent runners is identical.

The value of the inlet diameter dm1 of described point of spacer requires that (dm1-dh)/(dt-dh) is close to 0.618 and to being worth rounding greatly, and meet golden section principle, wherein dh is the outside diameter of inner casing, and dt is the interior circular diameter of shell.

The value of the outlet diameter dm2 of described point of spacer require annular and separation cover and two that inner casing and shell are formed annular overcurrent runners to go out water speed equal.Meet the rectification requirement of rectifier, reduce rectification loss, raise the efficiency.

As preferably, the inlet diameter dm1 of described point of spacer is 1515mm, and the outlet diameter dm2 of described point of spacer is 1451.5mm; Or the inlet diameter dm1 of described point of spacer is 1215mm, the outlet diameter dm2 of described point of spacer is 1164.3mm; Or the inlet diameter dm1 of described point of spacer is 2180mm, the outlet diameter dm2 of described point of spacer is 2056mm.

Beneficial effect: pump waterjet propulsor rectification part of the present invention, by between inner casing and body skin increase a section be the annular casing of aerofoil profile, the runner in impeller downstream is divided into two annular channels by this housing, exit design requires that the exit velocity of two annular sections is identical, the flow velocity difference in pump waterjet propulsor impeller downstream can be adjusted, to reduce the internal flow loss of pump waterjet propulsor, improve the thrust of pump waterjet propulsor under identical horsepower input.The present invention is directed to the merits and demerits of the axial wheel that the design of forced vortex method obtains, its advantage is not fully exerted, shortcoming is then suppressed in the adjustment mode of parts of the present invention.Therefore the present invention the core component of whole pump waterjet propulsor can be made to process simple, efficiency and power density higher.

Accompanying drawing explanation

Fig. 1 is lift and the velocity flow profile schematic diagram of streamline method design axial wheel in prior art;

Fig. 2 is pump waterjet propulsor assembling schematic diagram;

Fig. 3 is pump waterjet propulsor rectification part schematic diagram of the present invention;

Fig. 4 is Fig. 3 left view;

In figure: 1 housing, 2 impellers, 3 rectification parts, 4 inner casings, 5 shells, 6 points of spacers, 7 gussets.

Detailed description of the invention

Below in conjunction with accompanying drawing, the present invention is further described.

As shown in Figures 2 to 4, pump waterjet propulsor rectification part 3 of the present invention is a kind of rectifying devices being arranged on pump waterjet propulsor downstream, nozzle upstream, is specifically arranged on the downstream of housing 1 and impeller 2.This rectification part 3 is made up of by casting or being welded as a whole inner casing 4, shell 5, point spacer 6 and gusset 7, the annular casing of described point of spacer 6 to be a section be aerofoil profile, divide spacer 6 between inner casing 4 and shell 5, axial gusset 7 is in axial plane, vertical with inner casing 4, shell 5 and point spacer 6.The axial plane cross section dividing spacer 6 is the aerofoil profile section meeting hydrodynamic characteristics, and a point spacer 6 comprises import and outlet, and the runner in impeller 2 downstream is divided into two annular channels by this annular casing, and exit design requires that the exit velocity of two annular channels is identical.

Below in conjunction with specific embodiment and concrete numerical value, the present invention is described in further detail.

Embodiment one: thrust T=23516N, flow Q=10m ³/ s, as shown in Figure 3 construction parameter, the inner circle diameter d t=2000mm of shell 5, the outside diameter dh=735mm of inner casing 4, lift H=1.5m.

Calculate the inlet diameter dm1=1515mm of point spacer 6.

The axial wheel 2 obtained for forced vortex design exports the energy of namely rectification part 3 import and velocity distribution is

$\frac{c_u}{r}=C_1$

$c_m=\sqrt{C_2{r}^2+C_3}$

$H=\frac{{\mathrm{uc}}_u}{g}=\frac{{\mathrm{\ωc}}_{u}r}{g}=\frac{C_1\mathrm{\ω}{r}^2}{g}$

Above-mentioned various middle c _u, c _mbe respectively circumferencial direction component and the flow rate on axial surface of the absolute velocitye shown in Fig. 1, ω is cireular frequency, and u=ω r is the circumferential velocity of radius, C ₁, C ₂, C ₃for integral constant.

Axial wheel 2 lift that forced vortex design obtains is 2 curve forms along radial direction, makes its geometric mean equal with lift, namely makes

$\mathrm{\π}(r_t^2-r_h^2)H={\∫}_{r_h}^{r_t}\frac{C_1{\mathrm{\ωr}}^2}{g}2\mathrm{\πrdr}$

In formula, subscript t and h represents wheel rim (tip) and wheel hub (hub) position of impeller 2 respectively, obtains coefficient thus

$C_1=\frac{2\mathrm{gH}}{(r_t^2+r_h^2)\mathrm{\ω}}=1.8564$

Therefore the lift at wheel hub and wheel rim place is respectively

H _h＝0.357m，H _t＝2.643m

Again according to constant C ₁and C ₂relational expression

2C ₁(ω-C ₁)＝C ₂

Obtain

C ₂＝44.94803

Because actual design result and unitary theoretical analysis have bigger difference, at flow rate on axial surface formula

$c_m=\sqrt{C_2{r}^2+C_3}$

Middle interpolation parameter κ revises

$c_m=\mathrm{\κ}\sqrt{C_2{r}^2+C_3}$

So

$Q={\∫}_{r_h}^{r_t}{c}_m\·2\mathrm{\πrdr}=2\mathrm{\κ\π}{\∫}_{r_h}^{r_t}{\∫}_{r_h}^{r_t}r\sqrt{C_2{r}^2+C_3}\mathrm{dr}=\mathrm{\κ\π}{\∫}_{r_h}^{r_t}\sqrt{C_2{r}^2+C_3}d{r}^2$

Make χ=r ², then above formula becomes

$Q=\mathrm{\κ\π}{\∫}_{{r_h}^2}^{{r_t}^2}\sqrt{C_2\mathrm{\χ}+C_3}\mathrm{d\χ}$

$Q=\frac{2\mathrm{\κ\π}}{3C_2}{\sqrt{{(C_2\mathrm{\χ}+C_3)}^3}|}_{{r_h}^2}^{{r_t}^2}$

κ is a very important corrected parameter, and get κ=0.55 (when κ=1.0 then without solution) here, numerical solution above formula obtains

C ₃＝19.9769

Thus, the two-part flow of integration is respectively

$Q_1=\frac{2\mathrm{\κ\π}}{3C_2}{\sqrt{{(C_2\mathrm{\χ}+C_3)}^3}|}_{r_h^2}^{r_{m1}^2}=4.528m^3/s$

Require that the design of point spacer 6 makes two-part outlet flow rate on axial surface identical, obtain the outlet diameter dm2=1451.5mm of point spacer 6 thus

Embodiment two: thrust T=37012N, flow Q=10m ³/ s, the inner circle diameter d t=1600mm of shell 5, the outside diameter dh=585mm of inner casing 4, lift H=3.7m

Intermediate steps (substantially omitting) is with embodiment one

Calculate dm1=1215mm

$C_1=\frac{3\mathrm{gH}}{(r_t^2+r_h^2)\mathrm{\ω}}=.38206$

Therefore the lift at wheel hub and wheel rim place is respectively

H _h＝0.8726m，H _t＝6.5274m

Obtain

C ₂＝170.85218

Get κ=0.55, numerical solution obtains

C ₃＝48.7209

Thus, the two-part flow of integration is respectively

$Q_1=\frac{2\mathrm{\κ\π}}{3C_2}{\sqrt{{(C_2\mathrm{\χ}+C_3)}^3}|}_{r_h^2}^{r_{m1}^2}=4.528m^3/s$

Require that the design of point spacer 6 makes two-part outlet flow rate on axial surface identical, obtain the outlet diameter dm2=1164.3mm of point spacer 6 thus

Embodiment three: thrust T=134656N, flow Q=25m ³/ s, the inner circle diameter d t=2760mm of shell 5, the outside diameter dh=1235mm of inner casing 4, lift H=6.0m

Intermediate steps (substantially omitting) is with embodiment one

Calculate dm1=2180mm

$C_1=\frac{2\mathrm{gH}}{(r_t^2+r_h^2)\mathrm{\ω}}=3.27776$

Therefore the lift at wheel hub and wheel rim place is respectively

H _h＝2.0m，H _t＝10.0m

Obtain

C ₂＝81.48645

Get κ=0.55, numerical solution obtains

C ₃＝0.829943

Thus, the two-part flow of integration is respectively

$Q_1=\frac{2\mathrm{\κ\π}}{3C_2}{\sqrt{{(C_2\mathrm{\χ}+C_3)}^3}|}_{r_h^2}^{r_{m1}^2}=11.0925m^3/s$

Require that the design of point spacer 6 makes two-part outlet flow rate on axial surface identical, obtain the outlet diameter dm2=2056mm of point spacer 6 thus

The above is only the preferred embodiment of the present invention; be noted that for those skilled in the art; under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (7)

1. a pump waterjet propulsor rectification part, is characterized in that: this rectification part is arranged on the downstream of pump waterjet propulsor impeller, the upstream of nozzle, or forms with the housing integrally casting of nozzle and pump waterjet propulsor impeller outer; This rectification part comprises inner casing, shell, point spacer and gusset, and the annular casing of described point of spacer to be a section be aerofoil profile, point spacer is between inner casing and shell, and described gusset is in axial plane, vertical with inner casing, shell and point spacer.

2. pump waterjet propulsor rectification part according to claim 1, it is characterized in that: the axial plane cross section of described point of spacer is the aerofoil profile section meeting hydrodynamic characteristics, annular and separation cover forms two annular overcurrent runners respectively with inner casing and shell, the lower exit flow velocity of two annular overcurrent runners is identical.

3. pump waterjet propulsor rectification part according to claim 2, it is characterized in that: the value of the inlet diameter dm1 of described point of spacer requires that (dm1-dh)/(dt-dh) is close to 0.618 and to being worth rounding greatly, meet golden section principle, wherein dh is the outside diameter of inner casing, and dt is the interior circular diameter of shell.

4. pump waterjet propulsor rectification part according to claim 2, is characterized in that: the value of the outlet diameter dm2 of described point of spacer require two annular overcurrent runners to go out water speed equal.

5. pump waterjet propulsor rectification part according to claim 2, is characterized in that: the inlet diameter dm1 of described point of spacer is 1515mm, and the outlet diameter dm2 of described point of spacer is 1451.5mm.

6. pump waterjet propulsor rectification part according to claim 2, is characterized in that: the inlet diameter dm1 of described point of spacer is 1215mm, and the outlet diameter dm2 of described point of spacer is 1164.3mm.

7. pump waterjet propulsor rectification part according to claim 2, is characterized in that: the inlet diameter dm1 of described point of spacer is 2180mm, and the outlet diameter dm2 of described point of spacer is 2056mm.