CN100485194C - Centrifugal impeller - Google Patents

Abstract

The centrifugal impeller suitable for operating at high rotation speed condition is one open type impeller and has one vane wheel with 7 large vanes and 7 split vanes, one inducer wheel integrated with the vane wheel, and one back bending. It has an inlet hub radius of 9.5 mm, an inlet tip radius of 31.5 mm, vane wheel outlet radius of 43.7 mm, vane wheel outlet width of 6.5 mm, an obtuse tail edge and an outlet back bending angel of 7 deg. It has a blade profile curve defined by a cubic Bezier function.

Description

A kind of centrifugal impeller

Technical field

The present invention relates to a kind of centrifugal impeller, belong to turbomachine centrifugal compressor impeller technical field.

Background technique

In recent years, microminiature unmanned plane, target drone, cruise missile and all kinds of light-duty minute vehicle, obtained utilization widely and fast-developing in the modern military field, development work at the miniature turbine motor is subjected to increasing attention both at home and abroad, and has developed into a new research field.The microminiature turbine motor has advantages such as in light weight, that power is big, thrust weight ratio is high, energy density is big, in dual-use field wide application prospect is arranged.The centrifugal compressor characteristic is mild, and the single-stage pressure ratio is higher, and processing technology is better, is mainly used in the miniature turbine motor.Research tendency to the microminiature turbine motor is to reduce fuel consumption rate when further improving thrust weight ratio, and as its critical component, design obtains high performance microminiature centrifugal compressor and will directly affect the performance of miniature turbine motor.Reliably, the design of perfect centrifugal impeller, the performance of centrifugal compressor is produced great influence, and is directly connected to the complete machine performance of motor.Job requirements such as sound are striden in high rotating speed, high pressure ratio, import, will guarantee simultaneously to obtain working efficiency preferably, have increased the design difficulty of centrifugal impeller.

Summary of the invention

The objective of the invention is to design a kind of centrifugal impeller, adopt forming method how much, obtain a microminiature centrifugal impeller, this centrifugal impeller is inducer and unshrouded impeller palintrope of band, and the impeller blade profile adopts the cubic Bezier function to carry out the parametrization definition.Through computation fluid dynamics (being CFD) numerical calculation and experimental test, verify that this impeller performance is better, impeller adiabatic efficiency reaches 79.3%.

The present invention is a kind of centrifugal impeller, and its technological scheme is: this centrifugal impeller is inducer and unshrouded impeller palintrope of band.This impeller is made up of 7 big blades and 7 splitterr vanes, and inducer (not shown) and impeller are one.The impeller inlet hub radius is 9.5mm, and the import tip radlus is 31.5mm, and the impeller outlet radius is 43.7mm, and impeller outlet width is 6.5mm, blunt trailing edge, and outlet back bent angle is 7 °.The present invention adopts the blade profile curve of cubic Bezier function definition centrifugal impeller on the cross section of coaxial different radii.

A n Bezier can be expressed as usually:

$Q\left(t\right)=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{p}_i{B}_i^n\left(t\right)$

Wherein Q (t) is the coordinate of any point on the curve, p _i(0≤i≤n) is the corresponding scale value of doing of curve control point,

Be this smooth (being Bernstein) multinomial of Bonn, provide by following relation:

$B_i^n\left(t\right)=(1-t)B_i^{n-1}\left(t\right)+t{B}_{i-1}^{n-1}\left(t\right)$

Utilize the cubic Bezier function to determine that a curve only needs four control points, wherein two is end points, the slope of two other control end points.The cubic Bezier function can be expressed as:

Q(t)＝(1-t) ³P ₁+3t(1-t) ²P ₂+3t ²(1-t)P ₃+t ³P ₄

Wherein Q is some in the three-dimensional coordinate of a point on the curve, P _iBe the coordinate at corresponding four control points, the excursion of parametric t is [0,1].

Leaf basin and blade back are selected three cross sections respectively, obtain three curves, and Fig. 1 is the blade profile schematic cross-section of big blade, and blade profile curve is described below respectively:

Molded lines and blade profile such as Fig. 2 of obtaining on the big blade I cross section:

The leaf basin:

P ₁＝(19.9，3.0)，P ₂＝(6.119，8.595)

P ₃＝(5.686，18.791)，P ₄＝(4.58，24.52)

Blade back:

P ₁＝(2.05，23.81)，P ₂＝(3.861，15.927)

P ₃＝(4.492，7.65)，P ₄＝(17.27，3.0)

Molded lines and blade profile such as Fig. 3 of obtaining on the big blade II cross section:

The leaf basin:

P ₁＝(17.78，7.96)，P ₂＝(5.91，14.67)

P ₃＝(4.71，22.48)，P ₄＝(4.34，33.28)

Blade back:

P ₁＝(1.2，33.08)，P ₂＝(6.1084，1.773)

P ₃＝(6.02，12.218)，P ₄＝(17.78，7.22)

Molded lines and blade profile such as Fig. 4 of obtaining on the big blade III cross section:

The leaf basin:

P ₁＝(3.62，29.41)，P ₂＝(3.42，30.6)

P ₃＝(2.306，35.552)，P ₄＝(1.87，37.44)

Blade back:

P ₁＝(0.37，37.44)，P ₂＝(1.432，34.02)

P ₃＝(1.693，33.205)，P ₄＝(2.92，29.36)

Fig. 5 is the blade profile schematic cross-section of splitterr vanes, and blade profile curve is described below respectively:

The molded lines that obtains on the splitterr vanes I cross section and blade profile such as Fig. 6:

The leaf basin:

P ₁＝(-1.15，14.0)，P ₂＝(-1.622，16.573)

P ₃＝(-2.615，21.283)，P ₄＝(-3.05，24.03)

Blade back:

P ₁＝(-4.67，24.56)，P ₂＝(-4.085，21.171)

P ₃＝(-3.3，18.6)，P ₄＝(-2.15，14.0)

The molded lines that obtains on the splitterr vanes II cross section and blade profile such as Fig. 7:

The leaf basin:

P ₁＝(-3.85，14.0)，P ₂＝(-7.005，21.772)

P ₃＝(-7.21，22.662)，P ₄＝(-8.88，33.91)

Blade back:

P ₁＝(-10.76，34.26)，P ₂＝(-6.979，20.114)

P ₃＝(-9.754，27.045)，P ₄＝(-4.82，14.0)

The molded lines that obtains on the splitterr vanes III cross section and blade profile such as Fig. 8:

The leaf basin:

P ₁＝(-12.3，27.76)，P ₂＝(-12.54，29.172)

P ₃＝(-13.44，34.2)，P ₄＝(-14.15，37.25)

Blade back:

P ₁＝(-15.8，37.38)，P ₂＝(-15.55，36.604)

P ₃＝(-14.59，33.04)，P ₄＝(-12.78，27.92)

Like this, by the curve of vane wheel profile forming on the different radii cross section, just can obtain the profile of whole impeller.

A kind of centrifugal impeller of the present invention, its advantage and effect are:

1, design method is simple, directly determines to make the blade profile data on the cross section, convenient processing;

2, this impeller is in high rotating speed (112000r/min) work down, and impeller adiabatic efficiency reaches 79.3%, and the whole level of gas compressor pressure ratio reaches 4, and efficient reaches 70%.

Description of drawings

Figure 1 shows that big vane foil schematic cross-section

Figure 2 shows that the blade profile on the big blade I cross section

Figure 3 shows that the blade profile on the big blade II cross section

Figure 4 shows that the blade profile on the big blade III cross section

Figure 5 shows that splitterr vanes blade profile schematic cross-section

Figure 6 shows that the blade profile on the splitterr vanes I cross section

Figure 7 shows that the blade profile on the splitterr vanes II cross section

Figure 8 shows that the blade profile on the splitterr vanes III cross section

Figure 9 shows that centrifugal impeller 3D solid right elevation

Concrete label is among the figure:

1, leaf basin 2, blade back 3, big blade 4, small leaf

Embodiment

The present invention is a kind of centrifugal impeller, and its technological scheme is: this centrifugal impeller is band inducer, palintrope, unshrouded impeller.This impeller is made up of 7 big blades and 7 splitterr vanes, and inducer (not shown) and impeller are one.The impeller inlet hub radius is 9.5mm, and the import tip radlus is 31.5mm, and the impeller outlet radius is 43.7mm, and impeller outlet width is 6.5mm, blunt trailing edge, and outlet back bent angle is 7 °.The present invention adopts the blade profile curve of cubic Bezier function definition centrifugal impeller on the cross section of coaxial different radii.

A n Bezier can be expressed as usually:

$Q\left(t\right)=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{p}_i{B}_i^n\left(t\right)$

Wherein Q (t) is the coordinate of any point on the curve, p _i(0≤i≤n) is the corresponding scale value of doing of curve control point,

Be this smooth (being Bernstein) multinomial of Bonn, provide by following relation:

$B_i^n\left(t\right)=(1-t)B_i^{n-1}\left(t\right)+t{B}_{i-1}^{n-1}\left(t\right)$

Utilize the cubic Bezier function to determine that a curve only needs four control points, wherein two is end points, the slope of two other control end points.The cubic Bezier function can be expressed as:

Q(t)＝(1-t) ³P ₁+3t(1-t) ²P ₂+3t ²(1-t)P ₃+t ³P ₄

Wherein Q is some in the three-dimensional coordinate of a point on the curve, P _iBe the coordinate at corresponding four control points, the excursion of parametric t is [0,1].

Leaf basin and blade back are selected three cross sections respectively, obtain three curves, and Fig. 1 is the blade profile schematic cross-section of big blade, and blade profile curve is described below respectively:

Molded lines and blade profile such as Fig. 2 of obtaining on the big blade I cross section:

The leaf basin:

P ₁＝(19.9，3.0)，P ₂＝(6.119，8.595)

P ₃＝(5.686，18.791)，P ₄＝(4.58，24.52)

Blade back:

P ₁＝(2.05，23.81)，P ₂＝(3.861，15.927)

P ₃＝(4.492，7.65)，P ₄＝(17.27，3.0)

Molded lines and blade profile such as Fig. 3 of obtaining on the big blade II cross section:

The leaf basin:

P ₁＝(17.78，7.96)，P ₂＝(5.91，14.67)

P ₃＝(4.71，22.48)，P ₄＝(4.34，33.28)

Blade back:

P ₁＝(1.2，33.08)，P ₂＝(6.1084，1.773)

P ₃＝(6.02，12.218)，P ₄＝(17.78，7.22)

Molded lines and blade profile such as Fig. 4 of obtaining on the big blade III cross section:

The leaf basin:

P ₁＝(3.62，29.41)，P ₂＝(3.42，30.6)

P ₃＝(2.306，35.552)，P ₄＝(1.87，37.44)

Blade back:

P ₁＝(0.37，37.44)，P ₂＝(1.432，34.02)

P ₃＝(1.693，33.205)，P ₄＝(2.92，29.36)

Fig. 5 is the blade profile schematic cross-section of splitterr vanes, and blade profile curve is described below respectively:

The molded lines that obtains on the splitterr vanes I cross section and blade profile such as Fig. 6:

The leaf basin:

P ₁＝(-1.15，14.0)，P ₂＝(-1.622，16.573)

P ₃＝(-2.615，21.283)，P ₄＝(-3.05，24.03)

Blade back:

P ₁＝(-4.67，24.56)，P ₂＝(-4.085，21.171)

P ₃＝(-3.3，18.6)，P ₄＝(-2.15，14.0)

The molded lines that obtains on the splitterr vanes II cross section and blade profile such as Fig. 7:

The leaf basin:

P ₁＝(-3.85，14.0)，P ₂＝(-7.005，21.772)

P ₃＝(-7.21，22.662)，P ₄＝(-8.88，33.91)

Blade back:

P ₁＝(-10.76，34.26)，P ₂＝(-6.979，20.114)

P ₃＝(-9.754，27.045)，P ₄＝(-4.82，14.0)

The molded lines that obtains on the splitterr vanes III cross section and blade profile such as Fig. 8:

The leaf basin:

P ₁＝(-12.3，27.76)，P ₂＝(-12.54，29.172)

P ₃＝(-13.44，34.2)，P ₄＝(-14.15，37.25)

Blade back:

P ₁＝(-15.8，37.38)，P ₂＝(-15.55，36.604)

P ₃＝(-14.59，33.04)，P ₄＝(-12.78，27.92)

Like this, by the curve of vane wheel profile forming on the different radii cross section, just can obtain the profile of whole impeller.

To sum up,, use the Bezier curvilinear equation and generate blade profile how much, respectively big blade and small leaf are become three dimendional blade according to the order in each cross section is long-pending storied then according to the control point of above-mentioned big blade and each cross section blade profile of small leaf.

Claims (2)

1, a kind of centrifugal impeller, this centrifugal impeller are applicable to that rotating speed is under the high speed conditions of 112000r/min, is characterized in that: this centrifugal impeller is inducer and unshrouded impeller palintrope of band; This impeller is made up of 7 big blades and 7 small leaf that are used to shunt, and inducer and impeller are one; The impeller inlet hub radius is 9.5mm, and the import tip radlus is 31.5mm, and the impeller outlet radius is 43.7mm, and impeller outlet width is 6.5mm, blunt trailing edge, and outlet back bent angle is 7 °; This centrifugal impeller adopts the blade profile curve of cubic Bezier function definition centrifugal impeller on the cross section of coaxial different radii.

2, a kind of centrifugal impeller according to claim 1, it is characterized in that: this centrifugal impeller is applicable to microminiature air breathing engine or gas turbine.

Images