CN103016398A - Centrifugal impeller flow passage design method for controlling curvature distribution - Google Patents

Abstract

The invention belongs to a fluid mechanical design modeling method and particularly relates to a centrifugal impeller flow passage design method for controlling the curvature distribution. A meridional flow passage of a centrifugal impeller comprises the following design steps that the parametric forming is realized through controlling the axial distribution of the curvature of a wheel cover line and a wheel hub line; and then, an obtained wheel cover and an obtained wheel hub curve rotate for 360 degrees around a rotating shaft, and a wheel cover surface and a wheel hub surface are obtained. The design method has the advantages that the proper curvature distribution rule can be flexibly selected according to the flowing work applying condition of the centrifugal impeller through controlling the curvature of the flow passage curves, the work apply efficiency and the stable work boundary of the centrifugal impeller are improved, and the design method can be widely applied to various kinds of centrifugal and inclined flow type impeller mechanical flowing designs.

Description

A Design Method of Centrifugal Impeller Flow Channel by Controlling Curvature Distribution

technical field

The invention belongs to a fluid machine design modeling method, in particular to a centrifugal impeller flow path design method for controlling curvature distribution.

Background technique

Centrifugal impeller machinery is a core component of jet aeroengines, and is widely used in the field of functional conversion of various fluid compressions or fluid expansions. The design of the meridian channel of the centrifugal impeller machinery has a great influence on the performance of the centrifugal impeller machinery. However, there is no clear design criterion for the design of the meridian flow channel, which generally depends on the experience of the designer, and the design is relatively subjective and arbitrary. At present, the conventional design method of the wheel cover line and the wheel hub line is generally formed by connecting arcs and straight lines. This design method is easy to cause flow loss and reduce the work efficiency of centrifugal impeller machinery.

Contents of the invention

The purpose of the present invention is to provide a centrifugal impeller channel design method that controls the curvature distribution, has good flow performance, and can improve the functional work efficiency of centrifugal impeller machinery.

The technical scheme adopted in the present invention is:

The meridian channel of the centrifugal impeller is enveloped by the wheel cover line, hub line, inlet line, and outlet line. The design steps are:

(1) Parametrically formed by controlling the curvature distribution of the wheel cover line and the hub line in the axial direction; the curvature distribution law of the wheel cover line and the hub line is determined by the following formula: ,

，其中R₂是离心叶轮的出口半径；Among them, C(m) is the curvature of the wheel cover line or the hub line, m is the dimensionless length of the wheel cover line or the wheel hub line; μ is the dimensionless position of the maximum curvature, and the optimal value of μ is 0.4~0.6; A is the dimensionless magnitude of the curvature of the crown line or hub line, and

, where R ₂ is the outlet radius of the centrifugal impeller;

The specific steps to determine the wheel cover line and hub line are:

(101) According to the one-dimensional flow calculation method, respectively determine the positions of the four endpoints of the wheel cover line and the hub line;

(102) Divide the wheel cover line into n (50≤n≤200) segments, determine the axial coordinates of n-1 points except the two ends, according to the curvature k of the first point and the coordinates of the point ( Z ₁ , R ₁ ), determine the coordinates of the second point (Z ₂ , R ₂ ); then use the curvature k of the second point and the coordinates of this point to determine the coordinates of the third point (Z ₃ , R ₃ ); By analogy, the coordinates of all points of the wheel cover line are obtained;

(103) Fit n+1 points on the obtained wheel cover line with a smooth curve to obtain a smooth wheel cover curve;

(104) Obtain the hub curve by adopting the methods of steps (102) and (103);

(2) The wheel cover curve and hub curve obtained in step (1) are rotated 360° around the rotation axis to obtain the wheel cover surface and hub surface.

The maximum curvature radius amplitude A of the hub line is 0.3-0.8 times of the maximum curvature of the wheel cover line.

The present invention has following beneficial effect:

By controlling the curvature of the flow path curve, the appropriate curvature distribution law can be flexibly selected according to the flow and work of the centrifugal impeller, and the distribution of the flow load of the centrifugal impeller in the axial direction can be controlled, which improves the work efficiency and the stable working boundary of the centrifugal impeller, and can be widely used It is applied to the flow design of various centrifugal and oblique flow impeller machines.

Description of drawings

Fig. 1 is a schematic diagram of the structure principle of the present invention.

Fig. 2 is a schematic diagram of the meridian flow channel in Fig. 1 .

Figure 3 is a graph of a typical curvature profile for an implementation of the present invention.

Labels in the figure:

1-Wheel cover line; 2-Hub line; 3-Inlet line; 4-Exit line.

Detailed ways

The present invention provides a centrifugal impeller flow channel design method for controlling curvature distribution. The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

The axial longitudinal section of centrifugal impeller machinery is generally called meridian flow channel. The meridian flow channel is enveloped by the wheel cover line 1, the hub line 2, the inlet line 3 and the outlet line 4, as shown in Fig. 1 and Fig. 2 .

The design steps of the meridian flow channel are:

确定轮盖线曲率分布曲线，取μ=0.5，A=0.03，m在区间[0,1]内，e为自然常数2.718，因此获得C的分布曲线如图3中轮盖曲率所示。(1) According to the formula

To determine the curvature distribution curve of the wheel cover line, take μ=0.5, A=0.03, m is in the interval [0,1], and e is the natural constant 2.718, so the distribution curve of C obtained is shown in Figure 3 as shown in the wheel cover curvature.

(101) Take n=100 points on the curvature distribution line as the curvature value required for determining the curve points in the next step, as shown in the table below.

m% C m% C 1 0.011088 51 1.347303 2 0.013462 52 1.339243 3 0.016279 53 1.325917 4 0.019606 54 1.307484 5 0.02352 55 1.28416 6 0.028103 56 1.256217 7 0.033444 57 1.223976 8 0.039641 58 1.187802 9 0.046799 59 1.148096 10 0.055029 60 1.105287 11 0.064448 61 1.059826 12 0.075178 62 1.012178 13 0.087344 63 0.962814 14 0.101075 64 0.912201 15 0.116496 65 0.860798 16 0.133735 66 0.809049 17 0.152912 67 0.757376 18 0.17414 68 0.706173 19 0.197524 69 0.655803 20 0.223153 70 0.606594 twenty one 0.251102 71 0.558838 twenty two 0.281423 72 0.512787 twenty three 0.314147 73 0.468652 twenty four 0.349275 74 0.426606 25 0.386781 75 0.386781 26 0.426606 76 0.349275 27 0.468652 77 0.314147

28 0.512787 78 0.281423 29 0.558838 79 0.251102 30 0.606594 80 0.223153 31 0.655803 81 0.197524 32 0.706173 82 0.17414 33 0.757376 83 0.152912 34 0.809049 84 0.133735 35 0.860798 85 0.116496 36 0.912201 86 0.101075 37 0.962814 87 0.087344 38 1.012178 88 0.075178 39 1.059826 89 0.064448 40 1.105287 90 0.055029 41 1.148096 91 0.046799 42 1.187802 92 0.039641 43 1.223976 93 0.033444 44 1.256217 94 0.028103 45 1.28416 95 0.02352 46 1.307484 96 0.019606 47 1.325917 97 0.016279 48 1.339243 98 0.013462 49 1.347303 99 0.011088 50 1.35 100 0.009096

(102) According to the one-dimensional flow calculation method, determine the coordinates of the first and last endpoints of the wheel cover line as (-75,78.5) (-8.4,118), and the coordinates of the first and last endpoints of the hub line as (-75,30) (0,118);

(103) Divide the wheel cover line into 100 segments, determine the axial coordinates of 99 points except the two ends, and determine the first point according to the curvature C of the first point and the coordinates of this point (Z ₁ , R ₁ ). The coordinates of the second point (Z ₂ , R ₂ ); then use the curvature C of the second point and the coordinates of this point to determine the coordinates of the third point (Z ₃ , R ₃ ); and so on, to get all the wheel cover lines the coordinates of the point;

Z R -75 78.5 -73.43502035 78.49837151 -71.87004041 78.49723887 -70.30506015 78.49660208 -68.81463966 78.4964566 -67.36149893 78.49674775 -65.90835897 78.49794052 -64.49041769 78.50043056 -63.1428718 78.50401094

-61.79532991 78.50902705 -60.4478 78.5163 -59.19965419 78.52510629 -57.95152095 78.53598324 -56.70342316 78.54997346 -55.51736745 78.56645111 -54.36234894 78.58547891 -53.2074032 78.6083379 -52.0814135 78.63517143 -51.01321625 78.66477902 -49.94514409 78.69888829 -48.8773 78.739 -47.88962662 78.781556 -46.90216959 78.82948334 -45.91511564 78.88454202 -44.97727118 78.943993 -44.06420693 79.00856366 -43.1517497 79.08104449 -42.26209545 79.16068784 -41.41715175 79.24455363 -40.57306032 79.33702157 -39.7303 79.4402 -38.9472264 79.54598906 -38.16539107 79.66136073 -37.38548975 79.78847279 -36.64120868 79.92172112 -35.91558782 80.06294656 -35.19249573 80.21645047 -34.4864099 80.38031078 -33.81092076 80.55015465 -33.13862012 80.73273475 -32.4707 80.9299 -31.83930479 81.13118307 -31.21206294 81.34590452 -30.59032841 81.57541667 -29.98947406 81.81398306 -29.40166698 82.06376927 -28.82032767 82.3281936 -28.25072259 82.60561671 -27.69692694 82.89342318 -27.15061213 83.19571583 -26.613 83.5125 -26.08805929 83.84127543 -25.57185361 84.18427962 -25.06526527 84.54086465

-24.56604623 84.91276126 -24.07558341 85.29917647 -23.59542853 85.69835262 -23.12251306 86.11245916 -22.65380903 86.5448392 -22.19610716 86.98921534 -21.7493 87.4441 -21.29927336 87.92480732 -20.86081588 88.41647846 -20.43337189 88.91751556 -20.00551642 89.44151307 -19.58363389 89.98204787 -19.17292295 90.5311522 -18.76671878 91.09641676 -18.35960455 91.68695539 -17.96377109 92.28530572 -17.5782 92.8901 -17.18476376 93.53120341 -16.80244892 94.17918998 -16.43021125 94.83290251 -16.05606746 95.51357865 -15.68666375 96.21087025 -15.32729414 96.91340328 -14.97182242 97.63167977 -14.61541408 98.37716362 -14.2689692 99.12742719 -13.9316 99.8817 -13.58902351 100.6733133 -13.25620892 101.4691852 -12.93245342 102.268717 -12.60924113 103.0932455 -12.29132488 103.9322472 -11.98257072 104.7746709 -11.6791764 105.6299164 -11.37815372 106.5078659 -11.08641924 107.3890091 -10.8037 108.273 -10.52216891 109.185579 -10.25015068 110.1011232 -9.987505226 111.0193485 -9.730545926 111.9536834 -9.481440164 112.8974661 -9.242291884 113.8437931 -9.012212468 114.7971747 -8.790301913 115.7623325

-8.578864424 116.7299409 -8.4 118.0

(104) Fit the 101 points on the wheel cover line in the above table with a smooth curve to obtain a smooth wheel cover curve, as shown in Figure 2;

(105) Adopt the method of steps (102)-(104) to obtain the hub curve, as shown in Figure 2;

(2) The wheel cover curve and hub curve obtained in step (1) are rotated 360° around the rotation axis to obtain the wheel cover surface and hub surface.

Claims (2)

1. centrifugal impeller runner design method of controlling curvature distribution, the meridional channel of this centrifugal impeller is formed by wheel cap line, wheel hub line, inlet line, egress line envelope, it is characterized in that, and design procedure is:

(1) by control wheel cap line, the distribution in the axial direction of wheel hub line curvature, come parametrization to form; Wheel cap line and the wheel hub curvature of a curve regularity of distribution, adopt following formula to determine: ,

Wherein, C (m) is wheel cap line or wheel hub curvature of a curve, and m is the dimensionless length of wheel cap line or wheel hub line; μ is that the maximum curvature place flows to the position percent value, and the preferred value of μ is 0.4 ~ 0.6; A is the dimensionless amplitude of wheel cap line or wheel hub line curvature, and

, R wherein ₂It is the port radius that of centrifugal impeller;

The concrete steps of determining wheel cap line and wheel hub line are:

(101) determine respectively 4 endpoint locations of wheel cap line and wheel hub line according to the one dimension computational methods that flow;

(102) the wheel cap line is divided into n(50≤n≤200) section, determine n-1 the axial coordinate of putting except two-end-point, according to the curvature k of first point and this coordinate (Z ₁, R ₁), determine the coordinate (Z of second point ₂, R ₂); Then with curvature k and this point coordinates of second point, determine the coordinate (Z of the 3rd point ₃, R ₃); By that analogy, obtain the coordinate that the wheel cap line is had a few;

(103) n+1 point on the wheel cap line that obtains used smooth curve, just can obtain smooth wheel cap curve;

(104) method of employing step (102) and (103) obtains the wheel hub curve;

(2) the wheel cap curve that is obtained by step (1), wheel hub curve rotate 360 ° around running shaft, obtain taking turns capping and wheel hub surface.

2. a kind of centrifugal impeller runner design method of controlling curvature distribution according to claim 1 is characterized in that, wheel hub line maximum curvature radius value A is 0.3 ~ 0.8 times of wheel cap line maximum curvature value.

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