CN104791294A - Double-wave-structure hub modeling method for single-stage fan/air compressor - Google Patents

Abstract

The invention relates to a double-wave-structure hub modeling method for a single-stage fan/air compressor. The metal blockage effect of a rotor blade row and a stator blade row of the single-stage fan/air compressor is considered in the design process of a hub. The control parameters such as the blade tip weighting function, the blade root weighting function, the maximum concave position forward movement amount, the front end magnification ratio, the rear end magnification ratio and the smoothness parameter are introduced. A double-wave structure hub shape is formed after modeling. The control parameters are adjusted through an overall optimization algorithm in the modeling process. The hub curve when the heat insulation efficiency is highest is the optimized hub curve. The end area flow of the hub after optimization is improved. The flow capacity is increased. The work range of the fan/air compressor is widened. The overall performance of the fan/air compressor is improved.

Description

Single-stage fan/compressor double wave wave structural hub formative method

Technical field

What the present invention relates to is a kind of single-stage fan/compressor double wave wave structural hub formative method, belongs to the field of aero-gas turbine compression system end wall optimal design.

Background technique

The raising of engine thrust-weight ratio is the outstanding feature that engine technology level promotes, and mainly realizes by following two kinds of technological approaches: one is ensureing to increase motor power under the prerequisite that gross weight is constant; Two is ensureing to reduce engine weight under the prerequisite that gross thrust is constant.No matter adopt which kind of mode, the airload of compression system all can be made after all unprecedented soaring.And along with the raising of compressor stage load, under higher adverse pressure gradient, flow separation and petiolarea blocking phenomenon can be more outstanding, cause the efficiency of motor to reduce, and may bring out the rotating stall phenomenon of compression system.For the flowing in wheel hub district, because denseness is inherently larger, metal blocking is serious; Under higher airload condition, the flowing blocking in wheel hub district can be aggravated further.Now, traditional design method is faced with new challenges.

For separation and the aerodynamic loss of compression system petiolarea, Chinese scholars proposes multiple solution route: such as, by boundary layer suction technology, low energy stream is detached control separation and blocking; Delayed the generation be separated to low energy stream increase energy by synthesizing jet-flow and acoustically-driven.In addition, also have scholar novel geometrical construction form to be introduced in turbine hub design, and obtain great success, be now applied in aeroengine is commercially produced.And for compression system, due to the existence of high adverse pressure gradient, petiolarea blocking is more serious, still there is many limitations in the hub design method based on empirical parameter optimization, still locates the what exploratory stage at present.Researcher both domestic and external attempts coming in different ways to carry out moulding to the shape of compressor blade petiolarea, such as, designed boss shape by tectonic axis to function, control by regulating in passage the boss shape etc. that dot matrix regulates passage.Two kinds of methods are all pure starts with from mathematical method for this, the boss shape of tectonic implication design may not necessarily reach optimal effectiveness, the optimization method of regulable control dot matrix then needs to consume a large amount of computational resources and time, all cannot start with from physical essence and set up rational design method.In recent years, the people such as Li Qiushi, based on the thought of " area ratio ", propose the wheel hub shaping method that a class improves petiolarea blocking, and complete the optimal design of wheel hub for single-rotor compressor, achieve good effect.

This invention is mainly for the hub design of single-stage high-loaded fan/gas compressor, by introducing " double wave wave " structure can considering fan/compressor wheel hub rotor blade, stator blade metal blockage effect respectively, the high-loaded fan/gas compressor wheel hub Optimization Design of Development of Novel.

Summary of the invention

Target of the present invention improves the flowing of high load single-stage fan/compressor hub area, reduces blocking and be separated, and improves the aeroperformance of single-stage fan/compressor.Invent using traditional single stage fan/compressor blade and runner geometrical construction as benchmark, consider the impact of blade metal blocking on runner negotiability, the blocking of the metal of axially different position, different radial height upper blade is amounted to according to certain rule, and it is supplementary to carry out correspondence by wheel hub shaping to runner flow area.After amounting to rule parametrization to this, extract the multiple regulating parameter controlling the distribution of single-stage compressor hub type space of lines, by global optimization method, combination optimizing is carried out to controling parameters, then can obtain the novel hub design method that one take " double wave wave " structure as feature.Specific design thinking is as follows:

(1) the radial position computational methods of wheel hub wall molded line

In order to count the affecting laws of blade metal blockage effect to runner negotiability, in axially different position, blade being cut respectively with certain axial spacing, obtaining the shape of cross section of blade as shown in Figure 1.Cross section is divided into several foursquare unit, less than ignoring of 0.5 cellar area, is more than or equal to that 0.5 cellar area is then approximate is designated as a cellar area.Square shaped cells to the distance of wheel hub with unit center radial height for benchmark (the size round of distance), allly be the cross-section area of blade under this radial height apart from identical cellar area sum, different radial height d and metal blocked area A under then can obtaining axially different position respectively thus _dbetween the regularity of distribution.

Because the metal blocking of different heights lower blade is different on the impact of endwall flow, for simplifying the analysis, the present invention supposes that this impact linearly distributes, and the mode of Line Weight Function then can be adopted thus to amount to, and introduces blade tip weighted value W respectively _twith blade root weighted value W _rtwo controling parameters (regularity of distribution as shown in Figure 2).For rotor and the stator blade of fan/compressor level, devise different weighting functions respectively, weighting function representation is:

$f_{\mathrm{wv}}\left(d\right)=W_r-\frac{d}{R_i-r_i}\×(W_r-W_t)---\left(1\right)$

In formula, R _ifor the radius of casing under this cross section, r _ifor the radius of this cross section lower hub, d is the radial height of blocked area, f _wvd () is weighted value when radial height is d.Total blocked area under this cross section is:

S _i＝N _·ΣA _df _wv(d) (2)

Wherein, N is the number of this section blade, A _dfor radial height is the blocked area of d, S _ifor the total blocked area under this cross section.New hub radius is:

$R_{\mathrm{Ni}}=\sqrt{R_{\mathrm{Oi}}^2-S_i/\mathrm{\π}}---\left(3\right)$

In formula, R _oifor the original hub radius of this section, R _nifor the radius size that this section is new.

(2) the axial position computational methods of wheel hub wall molded line

By step (1), " double wave wave " structural design result of single-stage fan/compressor wheel hub molded line tentatively can be obtained, as shown in phantom in Figure 3.But, be not difficult to find out from figure, if only consider, rotor and the blocking of stator blade metal are to the local influence of wheel hub flowing, will inevitably cause the larger change along wheel hub wall molded line local curvature before and after blade, thus easily cause root of blade inlet air flow angle off-design operating mode.In order to optimize the curvature distribution of wheel hub wall molded line, introduce the maximum recess leading D of molded line respectively _m, front end magnification S _f, rear end magnification S _rdeng three controling parameters, particular location relation as shown in Figure 3.As can see from Figure 3, maximum recess leading D _mbe that the maximum recessed position that moulding produces is carried out axial adjustment, specify to move to channel entrance direction into just; Front end magnification be by maximum recess to wall molded line first moulding point between distance carry out stretching or compressing, S _f=d _fN/ d _f; Rear end magnification be then by maximum for wall molded line recess to last moulding point between distance carry out stretching or compressing, S _r=d _rN/ d _r.Magnification represents elongation when being greater than 1, represents shortening when magnification is less than 1.What figure chain lines showed expression is the new wall molded line obtained after the rotor hub depression section (1) step obtained stretches.By adding this three controling parameters, radial coordinate remains unchanged, and can obtain axial coordinate variation relation such as formula shown in (4):

Z _mN＝Z _m-D _m(4)

In formula, Z _mfor the initial axial coordinate of maximum recess is amounted in blade metal blocking; Z _mNthen represent the axial coordinate of maximum recess after axial adjustment.The computational methods of maximum recess front end moulding point and rear end moulding point axial coordinate can be obtained equally, see shown in formula (5), formula (6):

Z _fNi＝Z _mN-(Z _m-Z _fi)×S _f(5)

Z _rNi＝Z _mN-(Z _m-Z _ri)×S _r(6)

In formula, Z _fiand Z _ribe respectively the initial axial coordinate of maximum recess front end moulding point and rear end moulding point, Z _fNiand Z _rNithen represent the axial coordinate after maximum recess front end moulding point and the adjustment of rear end moulding point axial position respectively.

(3) optimal design of wheel hub wall molded line

The new radial coordinate of axially different position wheel hub section type line modelling point and axial coordinate is obtained by step (1) and step (2), point on wheel hub molded line outside sculpted zone remains unchanged, and then forms a series of new hub type line coordinates point after reconfiguring.In order to ensure the smooth of runner, adopt smoothing spline spline function to carry out spline-fit to it, wall molded line smooth degree controls by smoothing parameter SP.

Be optimized in the process of design to wheel hub, should ensure single-stage fan/compressor blade and casing geometric parameter constant.Blade tip weighted value, blade root weighted value, maximum recess leading, front end magnification and rear end magnification 5 controling parameters all can be introduced for each row's blade, choose different parameter values, according to the computational methods of above-mentioned (1) step and (2) step, one group of hub design result all can be obtained.And for fan/compressor level, rotor and stator two groups of leaf rows then corresponding 10 controling parameters, add the smoothing parameter SP of wheel hub, one has 11 controling parameters (W _t1, W _r1, D _m1, S _f1, S _r1, W _t2, W _r2, D _m2, S _f2, S _r2, SP).Thus, the optional adiabatic efficiency η drawing fan/compressor under flow setting type is as objective function, set " double wave wave " structure interface point position as constraint conditio simultaneously, global optimization approach is adopted to carry out combination optimizing to controling parameters, work as predetermined optimizing target parameter---the maximized controling parameters value of adiabatic efficiency η, can obtain optimum " double wave wave " hub design result.

Accompanying drawing explanation

Fig. 1 is that axially different position leaf cross-section metal blocked area amounts to schematic diagram;

Fig. 2 is that area weight function regularity of distribution schematic diagram is amounted in the blocking of blade different leaf height metal;

Fig. 3 is the maximum recess leading of wheel hub wall molded line, front end magnification and rear end magnification schematic diagram;

Fig. 4 is comparison diagram before and after single-stage fan/compressor wheel hub wall molded line is optimized;

Fig. 5 is pressure ratio---the flow curve comparison diagram before and after single-stage fan/compressor is optimized;

Fig. 6 is efficiency---the flow curve comparison diagram before and after single-stage fan/compressor is optimized.

Embodiment

Illustrate the specific embodiment of the present invention below, adopt the shape of said method to its wheel hub to redesign for the one-level in certain gas compressor, and utilize the effect of this optimization method of method validation of numerical simulation.

Gas compressor is the first order of certain high-pressure compressor, and design speed is 14359rpm, and design discharge is 88kg/s, Design compression ratio is 1.92, and design efficiency is 0.90, and rotor blade number is 53, stator blade number is 88, and the geometrical shape of blade and flow channel shape are all known.

One, new radial coordinate is calculated according to step (1)

From rotor forward position, divide a cross section every 2mm axial spacing, obtain the shape of cross section, obtain altogether 45 independently closed cross-section profiles.The computational methods of the sectional area regularity of distribution are now described with the 22nd cross section, and its contour shape as shown in Figure 1.With the grid of 0.1mm × 0.1mm, cross section profile is divided into foursquare unit totally 14137, the hub radius of this section is 246.04mm, casing radius is 295.97mm, calculate the radial height of each unit center, the cellar area summation identical to all height, is multiplied by the area 0.01mm of each unit ², obtain the distribution of blocked area under different radial height as shown in the table:

Radial height d (mm)	1	2	3	4	5	6	7	8	9	10	11	12	13
														Blocked area A d(mm 2)	4.07	4.13	4.16	4.1	4.14	4.29	4.23	4.17	4.16	4.12	4.07	4.03	3.97
Radial height d (mm)	14	15	16	17	18	19	20	21	22	23	24	25	26
														Blocked area A d(mm 2)	3.91	3.87	3.83	3.75	3.65	3.58	3.46	3.36	3.2	3.09	2.92	2.79	2.67
Radial height d (mm)	27	28	29	30	31	32	33	34	35	36	37	38	39
														Blocked area A d(mm 2)	2.55	2.4	2.26	2.18	2.09	2.05	1.95	1.84	1.82	1.82	1.79	1.72	1.71
Radial height d (mm)	40	41	42	43	44	45	46	47	48	49	50
														Blocked area A d(mm 2)	1.63	1.62	1.62	1.62	1.61	1.67	1.69	1.72	1.71	1.75	0.73

Blade tip weighted value and blade root weighted value are two controling parameters, and in actual optimization, value all may be different each time, for the ease of setting forth, get W at this _t=0 and W _r=1, obtaining weighting function is:

$f_{\mathrm{wv}}\left(d\right)=1-\frac{d}{295.97-246.04}\×(1-0)$

Calculate the weighting function value under corresponding radial height according to sectional area distribution table obtained above, the total blocked area obtained under this cross section is:

S ₂₂＝53·ΣA _df _wv(d)＝4554.58mm2

Then new under this cross section hub radius is:

$R_{N22}=\sqrt{{246.04}^2-4554/\mathrm{\π}}=243.08\mathrm{mm}$

All axial position cross sections are arranged to single-stage fan/compressor leaf and uses the method, then can obtain the radial coordinate that all axial cross section wheel hub wall molded line moulding points are new.

Two, new axial coordinate is calculated according to step (2)

In actual optimization process, these three controling parameters of maximum recess leading, front end magnification and rear end magnification all may be different in every suboptimization, for the ease of setting forth, chooses D at this _m=3, S _f=1.2 and S _r=0.8, and be designed to example with rotor leaf skate hub and be described.Rotor leaf row vertically cutting obtains 29 axial cross sections, and what the blocked area after amounting to was maximum is the 12nd cross section, its initial axial coordinate Z _m=575mm, calculating according to step (2) axial coordinate made new advances is:

Z _mN＝575-3＝572mm

To the wall profile coordinate point in a cross section, 11 before maximum recess, new axial position can be obtained respectively according to formula (5).With first Cross-section point for example, its initial axial coordinate is Z _f1=557mm, new axial coordinate is

Z _fN1＝572-(575-557)×1.2＝550.4mm

Equally, to the moulding point in all 17 cross sections after maximum recess, its corresponding new axial position coordinate can be obtained by formula (6).With last Cross-section point for example, its initial axial coordinate is Z _r29=611mm, new axial coordinate is

Z _rN29＝572-(575-611)×0.8＝600.8mm

For stator leaf row, adopt after using the same method, then can obtain the axial coordinate that single-stage fan/compressor all axial cross sections wheel hub wall molded line moulding point is new.

Three, according to step (3), boss shape is optimized

Obtain the new radial coordinate of wheel hub wall molded line axially different position moulding point and axial coordinate by above-mentioned steps, keep the coordinate of the exterior point of sculpted zone on molded line constant, reconfigure and form new hub type line coordinates point.Adopt smoothing spline spline function to carry out spline-fit to it, the less curve obtained of smoothing parameter SP value is more smooth, and this parameter obtains optimum value as controling parameters by optimizer, has so far obtained new wheel hub curve shape.

Ensure fan/compressor blade and casing geometric parameter constant, new wheel hub curve is utilized to regenerate computing grid, the boundary conditions of setup algorithm, the rotational speed of rotor is 14359rpm, and import stagnation temperature is 524.9K, import stagnation pressure is 652330Pa, airintake direction is axial admission, and outgoing quality flow is 89kg/s, and radial pressure balances, solid-surface is without slip boundary condition, reads the adiabatic efficiency of compressor stage after calculating convergence.

Above-mentioned steps is called in optimizer, and optimized algorithm selects archipelago genetic algorithm, and the number on island is 3, population number on each island is 35, the algebraically of evolving was 15 generations, and crossing-over rate is 1.0, and aberration rate and mobility are 0.01, in 11 controling parameters, the scope of 4 weighting functions is [0,1], and the scope of 4 magnifications is [0.5,2], Dm ₁scope be [-8,12], Dm ₂scope be [-8,10], the scope of smoothing parameter SP is [0,1], and simultaneously restrict rotor leaf row molded line tail before the axial position of stator leaf row molded line forward position, solves target and maximizes for making adiabatic efficiency in position vertically.Obtain an optimal solution through 1575 step iterative computation, as shown in Figure 4, in figure, solid line is original wheel hub to the boss shape after optimization, and dot and dash line is the wheel hub after optimizing, and the wheel hub after optimization is " double wave wave " structure.

Four, to the checking of optimum results

Carry out numerical simulation analysis to the original wheel hub in Fig. 4 and the wheel hub two kinds of situations after optimizing, the performance curve before and after being optimized, pressure ratio---flow curve comparison diagram and efficiency---flow curve comparison diagram respectively as shown in Figure 5, Figure 6.As can be seen from the figure, stable operation range after optimization broadens, because blade root blocking reduces, the flow of stifled point becomes large, simultaneously to blade root flowing improvement make whole operating range internal efficiency and pressure ratio all high than original wheel hub, wherein the relatively original wheel hub best efficiency point of the efficiency of best efficiency point improves 0.7 percentage point.

Claims (3)

1. single-stage fan/compressor double wave wave structural hub formative method, is characterized in that introducing blade tip weighted value W in design process _t, blade root weighted value W _r, maximum recess leading D _m, front end magnification S _f, rear end magnification S _rand the controling parameters such as smoothing parameter SP.Can independently propose, according to the given constraint conditio of geometric relationship between leaf row for each leaf row controling parameters.

2. carry out moulding according to the controling parameters introduced in claim 1, after it is characterized in that moulding, single-stage fan/compressor moulding rear-wheel hub shape is the structure of " double wave wave ".With traditional light wall single-stage fan/compressor blade and runner geometrical construction for benchmark, the computational methods of 11 controling parameters values are amounted to according to claim 1 transfer cotyledon row, static leaf row and turn quiet handing-over constraint, obtain radial coordinate that on wheel hub wall molded line, moulding point is new and axial coordinate, adopt smoothing spline spline function to carry out spline-fit to new wheel hub coordinate points, " double wave wave " structural hub design proposal of aeroperformance excellence can be obtained when the optimum value of controling parameters.

3. the optimum sampling process of controling parameters in claim 2, it is characterized in that adopting global optimization approach to carry out combination optimizing to controling parameters, the method of numerical simulation is adopted to calculate single-stage fan/compressor during different wheel hub wall molded line, the excursion of controling parameters in restriction claim 1, the adiabatic efficiency of single-stage fan/compressor when objective function is given flow, the boss shape when fan/compressor single stage adiabatic efficiency is maximum is the wheel hub wall molded line optimized and obtain.