Supersonic speed free-vortex wind-tunnel
Technical field
The present invention relates to a kind of wind-tunnel, relate in particular to a kind of supersonic speed free-vortex wind-tunnel.
Background technology
Development along with modern aeromechanics technology, the mechanism of aerodynamics Study on Problems is more and more important, as typically being flowed to compressible the flowing that curvature influences, the research of supersonic speed free-vortex not only has broad application background but also has the most important theories meaning.
Supersonic speed free-vortex velocity field satisfies free-vortex and distributes, and promptly the product of flowing velocity and flow curvature radius is a constant.Because flowing velocity is higher, its flow field has non-permanent and multiple dimensioned feature, the constant flow imaging technique is the important means of these features of research, it needs the free-vortex wind-tunnel to have the good optical measurement environment, and corresponding wind-tunnel optical window need design at the characteristics of research object.
Monograph " supersonic speed free-vortex aerodynamic window's and optical quality thereof " (Yi Shi and etc., publishing house of the National University of Defense technology, 2005) the free-vortex jet pipe method for designing (a kind of typical non-uniform flow jet pipe) found the solution based on the subregion of shortest length jet pipe (MLN) has been proposed, this method design process is as follows:
1) adopt the MLN method for designing to obtain a symmetrical jet pipe profile curve;
2) flow parameter on extraction MLN nozzle exit border is as asymmetric section inlet boundary condition;
3) be divided into several zones such as equal uniform flow district, simple wave district and non-simple wave district with asymmetric section; And
4) utilize free-vortex relational expression, Prandtl-mayer's relation and mass conservation relation to determine the wall curve in asymmetric district.
Adopt this method can access needed free-vortex jet pipe profile curve, numerical value checking result shows that designed jet pipe profile can generate needed free-vortex flow field.
Though the method for designing of existing free-vortex aerodynamic window's does not also have corresponding free-vortex wind-tunnel design proposal at present.
Prior art is mainly emphasized the profile design of free-vortex jet pipe and the design of free-vortex aerodynamic window's, can't directly expand to the design of free-vortex wind-tunnel.
Also there are some deficiencies in existing wind-tunnel designing technique for the research of supersonic speed flow mechanism: the one, and incoming flow turbulivity height, the 2nd, the optic test environment is relatively poor, be difficult to observe jet pipe internal edges interlayer, the 3rd, flox condition is not ideal enough, when especially paying close attention to two-dimensional flow field, sidewall disturbs the three-dismensional effect of bringing obvious.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of wind tunnel device that produces supersonic speed free-vortex flow field, and the free-vortex relational expression is satisfied in this wind tunnel experiment section flow field, and is convenient to the enforcement of optics non-contact testing technology.
For solving the problems of the technologies described above, the invention provides a kind of supersonic speed free-vortex wind-tunnel, it is characterized in that comprise: transition section is used to introduce air-flow; Stable section is connected the downstream of transition section, because steady air flow reduces aerodynamic noise; And jet pipe experimental section, be connected the downstream of stable section, the perisporium of jet pipe experimental section is formed with transparent window, and comprise: spout portion, be configured to the free-vortex nozzle structure, accelerate to supersonic speed free-vortex state with the air-flow in the future self-stabilization section, and experiment portion, be arranged on the downstream of spout portion.
Further, supersonic speed free-vortex wind-tunnel also comprises diffuser, has the inner-cavity structure that shrinks along towards downstream direction.
Further, the xsect of transition section is by the change shape of circular contour to the rectangular profile transition from the upstream extremity downstream end.
Further, the xsect of stable section is rectangular, comprises the periphery wall that parallels and internal perisporium and two sidewalls that are connected described periphery wall and internal perisporium.
Further, the xsect of jet pipe experimental section is rectangular, and perisporium comprises periphery wall with internal perisporium and be connected periphery wall and two sidewalls of internal perisporium, and periphery wall and internal perisporium form free-vortex jet pipe profile curve.
Further, the ratio of width to height of jet pipe experimental section is greater than 4.
Further, four perisporiums of the experiment portion of jet pipe experimental section all are formed with transparent window.
Further, transparent window extends in the perisporium in spout portion zone.
Further, on the wall of jet pipe experimental section the FLOW CONTROL panel can also be set.
Further, also comprise fairing in the stable section, fairing comprises honeycomb and husky net.
The present invention has following technique effect:
1. by a spout portion and experiment portion are set in the jet pipe experimental section of wind-tunnel, and make this spout portion be configured to the free-vortex nozzle structure, on the perisporium of experiment portion, be formed with transparent window, thereby the supersonic speed free-vortex flow field that in wind-tunnel, can obtain, and can pass through transparent window, realize the free-vortex flow field in the wind-tunnel is observed and the optics non-contact testing.
2. the ratio of width to height of jet pipe experimental section is set to greater than 4, is preferably greater than 5, connects the gas viscosity effect of sidewall about can eliminating effectively to the free-vortex influence on flow field, to obtain desirable flow field fluidised form.
3. by transparent window is extended in the perisporium in described spout portion zone, can observe formation front and back evolution process all sidedly with the research freedom swirling flow field.
4. be provided with optical glass by four perisporiums, can adopt optics non-contact testing technology to observe the flow field better at the jet pipe experimental section.
Except purpose described above, feature and advantage, the present invention also has other purpose, feature and advantage.With reference to figure, the present invention is further detailed explanation below.
Description of drawings
Accompanying drawing is used to provide further understanding of the present invention, constitutes the application's a part, and illustrative examples of the present invention and explanation thereof are used to explain the present invention, do not constitute improper qualification of the present invention.In the accompanying drawings:
Fig. 1 shows the one-piece construction synoptic diagram of supersonic speed free-vortex wind-tunnel of the present invention.
Embodiment
Below in conjunction with accompanying drawing embodiments of the invention are elaborated, but the multitude of different ways that the present invention can be defined by the claims and cover is implemented.
Alleged herein periphery wall is meant the perisporium that is positioned in the construction of wind tunnel than the distally for position, free-vortex center, internal perisporium is meant the perisporium that is positioned in the construction of wind tunnel than nearside for position, free-vortex center.
As shown in Figure 1, according to supersonic speed free-vortex wind-tunnel of the present invention, comprise: preceding transition section 1, be used to introduce air-flow, and air-flow carried out first order rectification, the irregular airflow flowing in the external world is made it to form the air-flow with certain flow characteristics by preceding transition section 1, get ready for it enters stable section 2; Stable section 2 is connected the downstream of transition section 1, is used for the air-flow that the past transition section 1 flows into is wherein carried out second level rectification, makes air-flow form the needed flow characteristics of experiment, and air-flow is entered in the jet pipe experimental section 3 so that experimentize; Jet pipe experimental section 3 is connected the downstream of stable section 2, its perisporium is formed with transparent window, and comprise: spout portion 31, spout portion 31 is configured to the free-vortex nozzle structure, the air-flow of self-stabilization section 2 accelerates to the free-vortex state in the future, can make the velocity field of wind tunnel experiment portion inlet air flow satisfy the distribution of supersonic speed free-vortex; Experiment portion 32 is positioned at the downstream of spout portion 31, and is preferably integrally formed with spout portion.By the transparent window of jet pipe experimental section 3, can adopt optics non-contact testing technology that the free-vortex flow field that forms in the jet pipe experimental section is observed.In order to carry out better optics non-contact testing, so that the characteristic in supersonic speed free-vortex flow field is studied, preferably, on four perisporiums of jet pipe experimental section, all be formed with transparent window, wall all is equipped with optical glass, transparent window extends in the perisporium in spout portion 31 zones, so that observe all sidedly and the evolution process of the formation front and back of research freedom swirling flow field.
Be provided with diffuser 4 in the downstream of jet pipe experimental section 3, have the inner-cavity structure that shrinks along towards downstream direction.Diffuser 4 can to carry out diffusion energy-conservation to enter wherein the air-flow of having debugged in jet pipe experimental section 3, and improving the startability of wind-tunnel, and the air-flow after will handling is sent into the next one stage.
In the present embodiment, the xsect of the transition section 1 of supersonic speed free-vortex wind-tunnel is by the change shape of circular contour to the rectangular profile transition from the upstream extremity downstream end.The porch circular contour can be connected with the circular air outlet of outside blowing device easily.If the air outlet of outside blowing device is a rectangle, then the transition section upstream extremity only need dispose corresponding rectangular profile and gets final product.The downstream end that transition section 1 is connected with stable section 2 forms rectangular profile, can well be connected with the rectangular profile of stable section 2.
The xsect of stable section 2 is rectangular, comprises that the periphery wall that parallels with internal perisporium and be connected periphery wall and two sidewalls of internal perisporium, can make stable therein the flowing of gas that enters from transition section 1.The xsect of jet pipe experimental section 3 is rectangular, comprise that periphery wall is with internal perisporium and be connected periphery wall and two sidewalls of internal perisporium, periphery wall and internal perisporium form free-vortex jet pipe profile curve, can make the air-flow that enters from stable section 2 form supersonic speed free-vortex flow field along free-vortex jet pipe profile curve.
In order to overcome the existing relatively poor problem of Flow Field in Wind Tunnel two-dimensional characteristics, the ratio of width to height of jet pipe experimental section 3 of the present invention (promptly, wide and high ratio, mean the ratio of width to height of passage in the jet pipe experimental section, can recently calculating according to distance between the sidewall of the left and right sides and the distance between the internal and external peripheral wall) greater than 4, connect the gas viscosity effect of sidewall about can eliminating effectively to the free-vortex influence on flow field, to obtain desirable flow field fluidised form.Preferably, its ratio of width to height can be set to more than or equal to 5.
As a preferred embodiment of the present invention, comprise fairing in the stable section 2, fairing comprises honeycomb and husky net, and honeycomb can effectively suppress the horizontal pulsation of incoming flow, and it is the small scale vortex that husky net can make the large scale vortex cracked.The whole processing of jet pipe experimental section profile global design to optimize the jet pipe curve, reduces the jet pipe boundary layer thickness, and clutter reduction produces.
When carrying out boundary layer research, on the supersonic speed free-vortex wind tunnel nozzle experimental section wall FLOW CONTROL panel 33 can also be set, can change its surface texture structure (superficial makings that comprises overall region or regional area, the bearing of trend of roughness, the picture on surface whether striped or other shapes are arranged, striped or other patterns etc. for example) realizes fluidised form control, for example can adopt hyperfine machining control roughness.
By foregoing description as can be known, according to supersonic speed free-vortex wind-tunnel of the present invention, realized that the velocity field of wind tunnel experiment portion inlet air flow satisfies the distribution of supersonic speed free-vortex, thereby in wind-tunnel, can obtain desirable supersonic speed free-vortex flow field; Connect the gas viscosity effect of sidewall about can eliminating effectively to the free-vortex influence on flow field, to obtain desirable flow field fluidised form; Can observe formation front and back evolution process all sidedly with the research freedom vortex; Can realize controllable flow field fluidised form, flow field quality is good, and two-dimensional characteristics is good.
The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.