CN104316287A - Two-dimensional variable-mach-number spray pipe and supersonic-velocity variable-mach-number wind tunnel using same - Google Patents

Abstract

The invention discloses a two-dimensional variable-mach-number spray pipe and a supersonic-velocity variable-mach-number wind tunnel using same. The two-dimensional variable-mach-number spray pipe comprises a first wall face and a second wall face opposite to the first wall face, wherein the first wall face comprises a circular-arc expanding wall face, the second wall face comprises a wave absorbing wall face for wave absorption, at least one of the first wall face and the second wall face is a variable-mach-number movable wall face rotating around the circle center of the circular-arc expanding wall face. Compared with a sliding block type spray pipe, the flow field quality of the two-dimensional variable-mach-number spray pipe is improved. Compared with a flexible-wall spray pipe, the spray pipe performs rotating one-freedom-degree motion, a structure and a control mechanism of the spray pipe are simple, and cost is low.

Description

Two dimension becomes Mach number nozzle and uses the supersonic speed of this jet pipe to become Mach number wind-tunnel

Technical field

The present invention relates to a kind of two dimension to become Mach number nozzle and use the supersonic speed of this jet pipe to become Mach number wind-tunnel.

Background technology

Supersonic nozzle is widely used in the equipment such as high-speed aircraft, rocket, supersonic wind tunnel, high-energy laser, injection vacuum pump, and the performance of nozzle flow field product confrontation equipment has important impact.Obtain suitable jet pipe wall molded line by certain designing technique, can greatly improve nozzle flow field quality, improve equipment performance, save reasearch funds.Supersonic nozzle is generally made up of contraction section and expansion segment, under certain pressure drives, gas accelerates gradually at contraction section, and reaches the velocity of sound at peri-laryngeal, then continue to accelerate at expansion segment, until at the supersonic flow going out Mach number required for interruption-forming and the distribution of flow direction angle.

Along with the dynamic (dynamical) high speed development of Modern air and widespread use, become Mach number nozzle continuously and there is more and more important application prospect.Particularly in wind-tunnel field, be furnished with become continuously Mach number nozzle wind-tunnel can simulated flight device accelerates, slow down, the state such as to cruise, once experiment is equivalent to traditional single Mach number nozzle and tests for tens times even up to a hundred times, and closer to the flight environment of vehicle of reality.

Two dimension becomes Mach number nozzle and mainly contains two kinds of change Mach number nozzle technology at present: slide block type jet pipe and flexible jet pipe (or being called flexible wall jet pipe).For the centre-block type jet pipe in slide block type jet pipe, it realizes becoming Mach number by regulating central slider position to change throat area, in some cases central slider is changed into a series of slide block and forms plug needle nozzle; For the monolateral slide block type jet pipe in slide block type jet pipe, adopt asymmetric configuration, by a certain wall of translation, change throat opening area, realize becoming Mach number.Flexible jet pipe is the dominant form becoming Mach number nozzle at present, and the most large-scale supersonic wind tunnel in the world have employed flexible jet pipe.Flexible jet pipe is that steel plate is articulated with a series of pressurized strut end, change pressurized strut position can obtain various curved wall shape, realizes the change of jet pipe molded line, and then obtains various different Mach number with spring steel plate as the curved wall of jet pipe.Flexible jet pipe be divided into entirely scratch wall, branched thirty scratches wall, single thirty scratches wall type three kinds of forms.

Centre-block type jet pipe is due to the impact of central slider tail, exit flow field quality is general not high, although monolateral slide block type jet pipe flow field quality has certain improvement, only better in design Mach number Fluid field uniformity coefficient, non-design Mach number Fluid field quality is still poor; Flexible jet pipe processing and control technology all more complicated, cost is high, limits its application on small-sized wind tunnel; Slide block type jet pipe and flexible jet pipe all can not realize the complete wave absorption in test block in theory, only can accomplish to make jet pipe molded line close with Theory Solution as far as possible, make test block uniformity coefficient reach requirement of experiment.

Summary of the invention

The object of the invention is to provide a kind of two dimension to become Mach number nozzle, to make test block have good flow field quality in work range of Mach numbers.The present invention also aims to provide a kind of supersonic speed of this jet pipe that uses to become Mach number wind-tunnel.

For this reason, one aspect of the present invention provides a kind of two dimension and becomes Mach number nozzle, and comprise the first wall and the second wall on the other side, the first wall comprises circular arc expansion wall; And second wall comprise wave absorption wall for wave absorption, wherein, at least one in both the first wall and the second wall is can rotate around the expand center of circle of wall of circular arc with the movable wall becoming Mach number.

Further, the contraction section molded line close to nozzle throat of above-mentioned first wall and the second wall is circular arc molded line.

Further, the contraction section molded line away from nozzle throat of above-mentioned first wall and the second wall is connected with circular arc molded line and at joining place slope rate continuity.

Further, in above-mentioned jet pipe only wave absorption section wall through viscous correction.

Further, above-mentioned wave absorption section wall realizes viscous correction by the displacement thickness of a compressible boundary layer of being extrapolated by inviscid wall.

Further, there is basic uniform test block, a flow field in the flow field that above-mentioned first wall and the second wall are configured so that jet pipe, test block becomes in Mach number process at jet pipe and is Delta Region.

Further, the shape and size of above-mentioned Delta Region change in jet pipe change Mach number process.

Further, above-mentioned first wall also comprises the straight line wall be connected with circular arc expansion wall end, wherein straight line wall and circular arc expansion wall tangent.

According to a further aspect in the invention, provide a kind of supersonic speed and become Mach number wind-tunnel, comprise supersonic nozzle, this supersonic nozzle is become Mach number nozzle according to two dimension described above.

Compared with slide block type jet pipe, the flow field quality that two dimension of the present invention becomes Mach number nozzle improves; Compared with flexible jet pipe, the single-degree-of-freedom motion that jet pipe employing of the present invention rotates realizes becoming Mach number, and simply, cost is low for structure and control gear.

Except object described above, feature and advantage, other object, feature and advantage that the present invention has, will be described in further detail by reference to the accompanying drawings.

Accompanying drawing explanation

Forming the part of this instructions, showing the preferred embodiments of the present invention for understanding accompanying drawing of the present invention further, and be used for principle of the present invention is described together with instructions.In figure:

Fig. 1 is the schematic diagram that two dimension according to the present invention becomes Mach number nozzle;

Fig. 2 is that two dimension according to the present invention becomes Mach number nozzle design drawing;

Fig. 3 a to Fig. 3 d is the schematic diagram that two dimension according to the present invention becomes the Mach number isoline of Mach number nozzle under different operating mode;

Fig. 4 is each triangle test block shown in Fig. 3 a to Fig. 3 d in the Mach Number Distribution of vertical direction and horizontal direction.

Embodiment

Below in conjunction with accompanying drawing, embodiments of the invention are described in detail, but the multitude of different ways that the present invention can be defined by the claims and cover is implemented.

Fig. 1 is the schematic diagram that two dimension according to the present invention becomes Mach number nozzle, as Fig. 1 institute, two-dimensional nozzle of the present invention comprises lower wall surface 10 and upper wall surface 20 corresponding with it, wherein, lower wall surface comprises circular arc expansion wall 12, upper wall surface 20 comprises wave absorption wall 21, when a jet pipe wall rotates around the circular arc center of circle of circular arc expansion wall (owing to being relative motion, it is equivalent that two walls rotate), due to the rotational invariance of circular arc, wave absorption wall 21 can be eliminated completely to the rarefaction wave that the circular arc that expands in certain limit after throat produces, the triangle test block A forming complete wave absorption in theory when a nothing is glued (is isosceles triangle substantially, as Fig. 3 a, Fig. 3 b, Fig. 3 c, shown in Fig. 3 d).Different owing to rotating rear expansion wall arc length, the angle that air-flow turns over through expansion wall is also different, and therefore test block Mach number is different, realizes becoming Mach number.

In a preferred embodiment, two dimension of the present invention becomes acceleration region in Mach number nozzle interior flow field is simple wave district.So-called simple wave district refers to that mach line is straight line, and on every bar mach line, flow state is identical.Its flow direction is determined by Pu Langte – Mayer function.In such jet pipe two wall, have a wall only to play effect to flow expansion, i.e. circular arc expansion wall, another wall only plays the effect of wave absorption, i.e. wave absorption wall.

Introduce the design process of jet pipe of the present invention below:

One, without sticky Profile Design

In conjunction with reference to figure 1, wall 10 is added straight line wall 13 formed by contraction section wall 11, circular arc expansion wall 12 in figure 2 the lower, and circular arc radius-of-curvature is r, and circular arc and straight line tie point are a some P _d, coincide with y-axis.Nozzle throat height is A ^*, design Mach 2 ship Ma _d.If the rarefaction wave that on circular arc expansion wall 12, any point P sends and wave absorption wall 21 meet at Q.Mach number on rarefaction wave (Mach wave) PQ is provided by following formula:

△ν＝ν(Ma _d)-ν(Ma _PQ) (1)

In formula, ν (Ma) is Prandtl-Mayer function:

$v\left(\mathrm{Ma}\right)=\sqrt{\frac{\mathrm{\γ}+1}{\mathrm{\γ}-1}}\arctan \left(\sqrt{\frac{\mathrm{\γ}-1}{\mathrm{\γ}+1}\sqrt{{\mathrm{Ma}}^2}-1}\right)-\arctan \sqrt{{\mathrm{Ma}}^2-1}---\left(2\right)$

PQ length is provided by formula (3)-(5):

PQ＝A _PQ/sinμ _PQ (3)

${\left(\frac{A_{\mathrm{PQ}}}{A^{*}}\right)}^2=\frac{1}{{\mathrm{Ma}}_{\mathrm{PQ}}^2}{\left(\frac{2}{\mathrm{\γ}+1}(1+\frac{\mathrm{\γ}-1}{2}{\mathrm{Ma}}_{\mathrm{PQ}}^2)\right)}^{\frac{\mathrm{\γ}+1}{\mathrm{\γ}-1}}---\left(4\right)$

${\mathrm{\μ}}_{\mathrm{PQ}}=\arcsin \left(\frac{1}{{\mathrm{Ma}}_{\mathrm{PQ}}}\right)---\left(5\right)$

By upper, can the coordinate of invocation point Q under polar coordinate system, to be namely the parametric equation of variable with Ma under polar coordinates be wave absorption wall:

$\left\{\begin{array}{c}{\mathrm{\ρ}}_Q=\sqrt{{\mathrm{\γ}}^2+{\mathrm{PQ}}^2+2\mathrm{rPQ}\sin \left({\mathrm{\μ}}_{\mathrm{PQ}}\right)}\\ {\mathrm{\φ}}_Q=\frac{\mathrm{\π}}{2}+\mathrm{\Δv}-\arcsin \left(\frac{\mathrm{PQ}}{\mathrm{OQ}}\cos {\mathrm{\μ}}_{\mathrm{PQ}}\right)\end{array}\right.----\left(6\right)$

Two, contraction section Profile Design

Become in Mach number process at jet pipe, when actual Mach number comparatively designs Mach number height, in the first wall, the contraction section molded line of peri-laryngeal transfers expansion segment molded line to, and this portion retracts segment type line is necessary for circular arc; Consider from symmetry, the second wall contraction section also advises adopting circular arc molded line close to the molded line that throat locates.Contraction section molded line away from place of throat can adopt general contraction section molded line formula, as Vickers curve, bicubic curve, bicircular arcs etc., but the operations such as the curve that need produce former formula rotates, intercepting, continuous with what meet with on the contraction section circular arc type line slope of peri-laryngeal.

Three, viscous correction

During jet pipe actual motion, due to the existence of viscosity, jet pipe wall can form boundary layer, and there is compression in boundary layer to air-flow, changes the wave system structure of jet pipe inside, must carry out viscous correction to jet pipe molded line.The method calculating compressible boundary layer has a lot, such as, adopt the displacement thickness δ of reference temperature method computation bound layer ^*, will to extrapolate a displacement thickness δ without sticky wall ^*, namely obtain the wall after viscous correction.In order to ensure nozzle expansion wall unchangeability under rotation, expansion wall is necessary for circular arc wall, and therefore, the boundary layer correction of expansion wall should be converted on wave absorption wall.

Fig. 3 a to Fig. 3 d is design Mach number Ma designed according to this invention _dthe two dimension of=3 becomes Mach number nozzle numerical simulation result under four different operating modes.Sequentially show at Ma=2.5 from Fig. 3 a to Fig. 3 d, 3.0,3.5, Mach number isoline under 4.0 4 operating modes, wherein, jet pipe is hermetically flexibly connected with experiment bin (vacuum storehouse), upper wall surface rotates, lower wall surface maintains static, and the base of triangle test block is positioned on straight line wall substantially, and corresponding jet pipe upper wall surface anglec of rotation △ θ is respectively-10.6 °, 0.0 °, 8.8 °, 16.0 ° (, for being rotated counterclockwise, negative sign is for turning clockwise for positive sign).Fig. 4 is for triangle test block under each operating mode (shown in Fig. 3 a to Fig. 3 d) is in the Mach Number Distribution of vertical direction and horizontal direction.Mach number relative error <1% can be drawn.

Compared with slide block type jet pipe, the flow field quality that two dimension of the present invention becomes Mach number nozzle will exceed a lot; Compared with flexible jet pipe, jet pipe of the present invention adopts the single-degree-of-freedom motion rotated, and simply, cost is low for structure and control gear; The present invention is in work range of Mach numbers, and jet pipe molded line is equal to theoretic complete wave absorption molded line all completely.

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (9)

1. two dimension becomes a Mach number nozzle, comprises the first wall (10) and the second wall on the other side (20), it is characterized in that,

Described first wall comprises circular arc expansion wall (12); And

Described second wall comprises the wave absorption wall (21) for wave absorption,

Wherein, at least one in the two of described first wall (10) and described second wall (20) be can around the center of circle rotation of described circular arc expansion wall (12) with the movable wall becoming Mach number.

2. two dimension according to claim 1 becomes Mach number nozzle, it is characterized in that,

The contraction section molded line (11) of described first wall (10) and the contraction section molded line (21) of described second wall (20) are close to described nozzle throat (A ^*) molded line at place is circular arc molded line.

3. two dimension according to claim 2 becomes Mach number nozzle, it is characterized in that,

The contraction section molded line (11) of described first wall (10) and the contraction section molded line (21) of described second wall (20) are away from described nozzle throat (A ^*) molded line at place is connected with described circular arc molded line and at joining place slope rate continuity.

4. two dimension according to claim 1 becomes Mach number nozzle, it is characterized in that,

In described jet pipe wall only described wave absorption segment type line through viscous correction.

5. two dimension according to claim 4 becomes Mach number nozzle, it is characterized in that,

Described wave absorption segment type line realizes viscous correction by the displacement thickness of a compressible boundary layer of being extrapolated by inviscid wall.

6. two dimension according to claim 1 becomes Mach number nozzle, it is characterized in that,

There is basic uniform test block (A), a flow field in the flow field that described first wall (10) and the second wall (20) are configured so that described jet pipe, described test block (A) becomes in Mach number process at described jet pipe and is Delta Region.

7. two dimension according to claim 6 becomes Mach number nozzle, it is characterized in that,

The shape and size of described test block (A) change in described jet pipe change Mach number process.

8. two dimension according to claim 6 becomes Mach number nozzle, it is characterized in that,

Described first wall (10) also comprises the straight line wall (13) be connected with described circular arc expansion wall (12) end, and described straight line wall (13) is tangent with described circular arc expansion wall (12).

9. supersonic speed becomes a Mach number wind-tunnel, comprises supersonic nozzle, it is characterized in that, described supersonic nozzle is that two dimension according to any one of claim 1 to 8 becomes Mach number nozzle.