CN102562654A - Blade profile design method for impeller of radial-flow air compressor - Google Patents

Abstract

The invention discloses a blade profile design method for an impeller of a radial-flow air compressor. A framed blade forming method utilizing the Lame ellipse as the trunk is used for designing the blade profile of the impeller and includes steps of determining a Lame blade profile curve equation as the twisting foundation according four constraint conditions including the front rake gamma or back rake gamma of the impeller, the blade mounting angle beta, the blade envelop angle phi b and the blade axial height Zm, and then determining the maximum twist amount Snm and the axial position proportion Kf of the maximum twist point, wherein the Kf=Zf/Zm, and the maximum twist amount Snm=Knq X (Sm-S0). On the premise of guaranteeing the gamma, the beta, the phi b and the Zm constant, the twist Lame curve equation can be obtained by building a twist amount displacement equation of ds=f(Z) to determine twist displacements of different Z-positions. The twist Lame ellipse is used as the blade profile curve in the design for the impeller of the radial-flow air compressor, and accordingly the method is a simple, adaptable and visual math processing method.

Description

A kind of radial-flow type compressor propeller Blade Design Method

Technical field

The invention belongs to the variable capacity field of mechanical technique, be specifically related to a kind of radial-flow type compressor propeller Blade Design Method.

Background technique

Along with improving constantly of turbosupercharged engine reinforcing degree, also harsh day by day to the reliability and the performance demands of turbosupercharger.Radial-flow type compressor propeller is the important component part in the turbosupercharger member, and its quality is most important to the turbosupercharged engine Effect on Performance.In order to obtain high performance compressor impeller, in design process, need do ternary aerodynamic flow field analysis and calculate it, calculate in order to cooperate three-dimensional flow, just must create the strong impeller design mould-forming method of plasticity so that impeller is optimized design.

Summary of the invention

The present invention will solve in order to obtain high performance compressor impeller exactly, and needs to adopt ternary aerodynamic flow field analysis to calculate, and must create the strong impeller design mould-forming method of plasticity impeller is optimized the problem of design.

The present invention realizes through following technological scheme:

1. radial-flow type compressor propeller Blade Design Method, this method be a kind of be the skeleton blade forming method of trunk with the Lame ellipse, promptly according to the impeller top rake γ that sets or back rake angle γ, blade angle β, blade envelope angle θ _bWith blade axial height Z _mFour big constraint conditios, confirm a Lame blade profile curve equation (1):

$S_l=c-d{[1-{\left(\frac{z+a}{b}\right)}^p]}^{\frac{1}{q}}---\left(1\right)$

The design of said Lame blade profile curve equation (1) may further comprise the steps:

A. given equation index p, q (p=q=2～3);

B. calculating place undetermined coefficient a, b, c, d;

C. with the Lame elliptic curve as the trunk in the blade framework, pass the impeller center line and the Lame blade profile curve is drawn straight line or the curve of series of parallel in the x-y plane along the z axle;

D. make these straight lines or envelope of curves face, constituted cambered surface in the blade;

E. enclose vane thickness at these straight lines or curve both sides according to certain rules, the envelope surface of its relative contour has just formed the pressure side and the suction surface of blade.

The oval blade profile curve of a kind of distortion Lame is according to impeller top rake γ or back rake angle γ, blade angle β, blade envelope angle θ _bWith blade axial height Z _mFour constraint conditios, create following distortion Lame curvilinear equation (2) and (3):

1)Z＝Z ₀～Z _f

$S_{\mathrm{nl}}=S_l-K_{\mathrm{nq}}(S_m-S_0){\left(\frac{Z-Z_0}{Z_f-Z_0}\right)}^{m_1{(Z_f-Z)}^{n_1}}---\left(2\right)$

In the formula:

$m_1=0.005\&times;{\left(\frac{Z_f-{\mathrm{<figure-callout\; id="0"\; label="Z"\; filenames="HDA0000128471660000011.png,HDA0000128471660000012.png"\; state="\{\{state\}\}">Z</figure-callout>}}_0}{8.25}\right)}^{1.638}$ $n_1=0.75\&times;{\left(\frac{51.5}{Z_f-Z_0}\right)}^{0.758}$

2)Z＝Z _f～Z _m

$S_{\mathrm{nl}}=S_l-K_{\mathrm{nq}}(S_m-S_0)[1-{\left(\frac{Z-Z_f}{Z_m-Z_f}\right)}^{m_2{(Z_m-Z)}^{n_2}}]---\left(3\right)$

In the formula:

$m_1=\frac{1.13}{{Z_m}^{0.5}}$ n ₁＝1.2

In the formula of (2) (3):

S _NlBe the arc length of distortion Lame blade profile curve, (mm);

S _lBe the arc length of original (benchmark) Lame blade profile curve, (mm);

K _NqBe twist angle coefficient, K _Nq=0～0.10;

S _mFor pressing blade envelope angle θ _bThe arc length of amounting to, (mm);

S ₀Be initial arc length (top rake γ is the shared arc length of definite value section), (mm);

Z ₀For γ is the axial length of definite value section (blade profile curve straightway), (mm);

Z _mBe the blade profile curve greatest axial length, (mm);

Z _fBe the axial position of maximum twist angle many places, (mm).

The design of said distortion Lame curvilinear equation (2) and (3) may further comprise the steps:

A. set up the foundation of an original Lame elliptic curve equation as distortion;

B. confirm a maximum twist angle S _NmAnd the residing axial position of maximum distortion point compares K _f, K _f=Z _f/ Z _m, general K _f=0.65～0.75, its maximum twist angle S _Nm=K _Nq* (S _m-S ₀), K _Nq=0～0.10;

C. guaranteeing γ, β, θ _b, Z _mUnder the constant prerequisite, create the distortion displacement amount that a ds=f (Z) twist angle displacement equation is confirmed different Z place.

The present invention compares with existing technology has following beneficial effect: adopt " distortion Lame is oval " as the blade profile curve in the radial-flow type compressor propeller design be one simple, be suitable for, mathematical processing methods intuitively.

Description of drawings

Fig. 1 is at D ₁The blade profile curve schematic representation that launches on the cylinder;

Fig. 2 is equation index p, the q schematic representation to the influence of Lame blade profile curve;

Fig. 3 is distortion Lame curve synoptic diagram;

Fig. 4 is K _f=0.70, K _NqThe different distortion Lame curves and the comparison schematic representation of original Lame curve;

Fig. 5 is K _Nq=0.06, different K _fThe schematic representation of comparison of distortion Lame curve.

Embodiment:

In impeller design, employing be " being the skeleton blade forming method of trunk with the Lame ellipse ", also promptly according to the impeller top rake γ (or back rake angle γ), blade angle β, the blade envelope angle θ that set _bWith blade axial height Z _mFour big constraint conditios are confirmed a Lame blade profile curve equation (referring to Fig. 1):

$S_l=c-d{[1-{\left(\frac{z+a}{b}\right)}^p]}^{\frac{1}{q}}---\left(1\right)$

In solution procedure, at first given equation index p, q (p=q=2～3), the undetermined coefficient of calculating place then a, b, c, d; With the Lame elliptic curve as the trunk in the blade framework; Then pass the impeller center line and the Lame blade profile curve is drawn straight line or the curve of series of parallel in the x-y plane, remake these straight lines then or the envelope of curves face has just constituted cambered surface in the blade along the z axle; Enclose vane thickness at these straight lines or curve both sides according to certain rules more afterwards, the envelope surface of its " relative contour " has just formed the pressure side and the suction surface of blade.Obviously, equation (1) is the principal element of decision blade trend.Though (1) the index p in the formula, q can select the value that solves different undetermined coefficient a, b, c, d in 2～3 scopes, the general parabolic equation Z=A * S of domestic than before extensive use decades ^0.5+ B * S has increased some flexibilities, but it is limited to be still ten minutes from the adjustable extent that blade profile curve is moved towards, and this can find out from Fig. 2.

In light of this situation, transfer to again in the world employing more flexibly " Bezier multinomial " as blade profile curve.But not only this mathematical method is very numerous and diverse, and the utmost point is not directly perceived.To this present situation, created " the oval blade profile curve of distortion Lame " again, also promptly according to above-mentioned γ, β, θ _b, Z _mFour constraint conditios are at first set up an original Lame elliptic curve equation and are then confirmed a maximum twist angle S again as the foundation of distortion _Nm, and the residing axial position of maximum distortion point compares K _f, K _f=Z _f/ Z _m, general K _f=0.65～0.75, its maximum twist angle S _Nm=K _Nq* (S _m-s ₀), K _Nq=0～0.10 (referring to Fig. 3) guaranteeing γ, β, θ _b, Z _mUnder the constant prerequisite, create the distortion displacement amount that a ds=f (Z) twist angle displacement equation is confirmed different Z place,, created following distortion Lame curvilinear equation through the repeated calculation practice:

1)Z＝Z ₀～Z _f

$S_{\mathrm{nl}}=S_l-K_{\mathrm{nq}}(S_m-S_0){\left(\frac{Z-Z_0}{Z_f-Z_0}\right)}^{m_1{(Z_f-Z)}^{n_1}}---\left(2\right)$

In the formula:

$m_1=0.005\&times;{\left(\frac{Z_f-{\mathrm{<figure-callout\; id="0"\; label="Z"\; filenames="HDA0000128471660000011.png,HDA0000128471660000012.png"\; state="\{\{state\}\}">Z</figure-callout>}}_0}{8.25}\right)}^{1.638}$ $n_1=0.75\&times;{\left(\frac{51.5}{Z_f-Z_0}\right)}^{0.758}$

2)Z＝Z _f～Z _m

$S_{\mathrm{nl}}=S_l-K_{\mathrm{nq}}(S_m-S_0)[1-{\left(\frac{Z-Z_f}{Z_m-Z_f}\right)}^{m_2{(Z_m-Z)}^{n_2}}]---\left(3\right)$

In the formula:

$m_1=\frac{1.13}{{Z_m}^{0.5}}$ n ₁＝1.2

In the formula of (2) (3):

S _NlBe the arc length of distortion Lame blade profile curve, (mm);

S _lBe the arc length of original (benchmark) Lame blade profile curve, (mm);

K _NqBe twist angle coefficient, K _Nq=0～0.10;

S _mFor pressing blade envelope angle θ _bThe arc length of amounting to, (mm);

S ₀Be initial arc length (top rake γ is the shared arc length of definite value section), (mm);

Z ₀For γ is the axial length of definite value section (blade profile curve straightway), (mm);

Z _mBe the blade profile curve greatest axial length, (mm);

Z _fBe the axial position of maximum twist angle many places, (mm).

Fig. 4 shows K _f=0.70, K _NqDo not twist the difference of Lame curve simultaneously; Fig. 5 shows K _Nq=0.06, K _fDifferent influences to the Lame curve.Can find out K _NqInfluence to the blade profile curve trend is bigger, and K _fInfluence what for little.

Claims (2)

1. a radial-flow type compressor propeller Blade Design Method is characterized in that, this method be a kind of be the skeleton blade forming method of trunk with the Lame ellipse, promptly according to the impeller top rake γ that sets or back rake angle γ, blade angle β, blade envelope angle θ _bWith blade axial height Z _mFour big constraint conditios, confirm a Lame blade profile curve equation (1):

$S_l=c-d{[1-{\left(\frac{z+a}{b}\right)}^p]}^{\frac{1}{q}}---\left(1\right)$

The design of said Lame blade profile curve equation (1) may further comprise the steps:

A. given equation index p, q (p=q=2～3);

B. calculating place undetermined coefficient a, b, c, d;

C. with the Lame elliptic curve as the trunk in the blade framework, pass the impeller center line and the Lame blade profile curve is drawn straight line or the curve of series of parallel in the x-y plane along the z axle;

D. make these straight lines or envelope of curves face, constituted cambered surface in the blade;

E. enclose vane thickness at these straight lines or curve both sides according to certain rules, the envelope surface of its relative contour has just formed the pressure side and the suction surface of blade.

2. according to the described a kind of radial-flow type compressor propeller Blade Design Method of claim 1, it is characterized in that the oval blade profile curve of a kind of distortion Lame is according to impeller top rake γ or back rake angle γ, blade angle β, blade envelope angle θ _bWith blade axial height Z _mFour constraint conditios, create following distortion Lame curvilinear equation (2) and (3):

1)Z＝Z ₀～Z _f

$S_{\mathrm{nl}}=S_l-K_{\mathrm{nq}}(S_m-S_0){\left(\frac{Z-Z_0}{Z_f-Z_0}\right)}^{m_1{(Z_f-Z)}^{n_1}}---\left(2\right)$

In the formula:

$m_1=0.005\&times;{\left(\frac{Z_f-Z_0}{8.25}\right)}^{1.638}$ $n_1=0.75\&times;{\left(\frac{51.5}{Z_f-Z_0}\right)}^{0.758}$

2)Z＝Z _f～Z _m

$S_{\mathrm{nl}}=S_l-K_{\mathrm{nq}}(S_m-S_0)[1-{\left(\frac{Z-Z_f}{Z_m-Z_f}\right)}^{m_2{(Z_m-Z)}^{n_2}}]---\left(3\right)$

In the formula:

$m_1=\frac{1.13}{{Z_m}^{0.5}}$ n ₁＝1.2

In the formula of (2) (3):

S _NlBe the arc length of distortion Lame blade profile curve, (mm);

S _lBe the arc length of original (benchmark) Lame blade profile curve, (mm);

K _NqBe twist angle coefficient, K _Nq=0～0.10;

S _mFor pressing blade envelope angle θ _bThe arc length of amounting to, (mm);

S ₀Be initial arc length (top rake γ is the shared arc length of definite value section), (mm);

Z ₀For γ is the axial length of definite value section (blade profile curve straightway), (mm);

Z _mBe the blade profile curve greatest axial length, (mm);

Z _fBe the axial position of maximum twist angle many places, (mm).

The design of said distortion Lame curvilinear equation (2) and (3) may further comprise the steps:

A. set up the foundation of an original Lame elliptic curve equation as distortion;

B. confirm a maximum twist angle S _NmAnd the residing axial position of maximum distortion point compares K _f, K _f=Z _f/ Z _m, general K _f=0.65～0.75, its maximum twist angle S _Nm=K _Nq* (S _m-S ₀), K _Nq=0～0.10;

C. guaranteeing γ, β, θ _b, Z _mUnder the constant prerequisite, create the distortion displacement amount that a ds=f (Z) twist angle displacement equation is confirmed different Z place.

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