CN110702358B - Semi-free jet flow experiment cabin and wind tunnel with same - Google Patents
Semi-free jet flow experiment cabin and wind tunnel with same Download PDFInfo
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- CN110702358B CN110702358B CN201911059027.7A CN201911059027A CN110702358B CN 110702358 B CN110702358 B CN 110702358B CN 201911059027 A CN201911059027 A CN 201911059027A CN 110702358 B CN110702358 B CN 110702358B
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Abstract
The invention discloses a semi-free jet flow experiment cabin and a wind tunnel with the same, wherein the semi-free jet flow experiment cabin is used for being connected with a spray pipe outlet of a spray pipe, is in a hollow tubular shape and comprises an upper cabin wall surface and a lower cabin wall surface which are arranged oppositely up and down, and two cabin side wall surfaces which are respectively and vertically connected with the upper cabin wall surface and the lower cabin wall surface, the upper cabin wall surface is a flat wall surface and is used for being in seamless butt joint with the spray pipe outlet and is in smooth transition connection with the upper pipe wall surface at the spray pipe outlet so as to prevent airflow from forming shock waves on the upper. The cabin side wall surface is a flat wall surface and is used for seamless butt joint with the outlet of the spray pipe and smooth transition connection with the pipe side wall surface corresponding to the outlet of the spray pipe. The rear section of the wall surface under the cabin is recessed inwards to form a nacelle for mounting an angle mechanism so as to facilitate the mounting and posture adjustment of a test model and avoid the influence of a formed wave system on the test measurement.
Description
Technical Field
The invention relates to the technical field of wind tunnels, in particular to a semi-free jet experiment cabin. In addition, the invention also relates to a wind tunnel comprising the semi-free jet experiment cabin.
Background
The supersonic/hypersonic wind tunnel is widely applied to model experiments of missiles, high-speed aircrafts, artificial satellites, space shuttles and aerospace planes, and is very important aerodynamic ground test equipment in the field of aerospace. The basic principle of the supersonic/hypersonic wind tunnel is as follows: the dry gas from the wind tunnel upstream is accelerated to supersonic speed/hypersonic speed from low speed through a spray pipe of the wind tunnel, the dry gas reaches the required Mach number at the outlet of the spray pipe, a test model is placed in an experiment cabin at the outlet of the spray pipe for pneumatic test, the high-speed gas flowing through the test model continuously flows towards the wind tunnel downstream and reaches a diffuser, and the diffuser decelerates and increases the pressure of the high-speed gas and discharges the high-speed gas to a vacuum tank or injects the high-speed gas into the atmosphere. The jet pipe and the experimental cabin are two very important parts of the supersonic speed/hypersonic speed wind tunnel, the jet pipe is used for accelerating airflow from low speed to supersonic speed/hypersonic speed so as to reach Mach number required by the experiment and ensure the quality of a flow field; the experiment chamber is a place for carrying out the experiment on the model, the installation and the posture adjustment of the model are carried out at the place, and the structural design of the experiment chamber is more important in the experiment process.
The existing supersonic/hypersonic experiment cabin structure is mostly in a direct connection mode or a free jet mode. The direct connection type experiment cabin is in seamless butt joint between the outlet of the spray pipe and the inlet of the experiment cabin, and is in smooth transition; the experiment cabin in the direct connection mode has the advantages that the inlet of the experiment cabin and the outlet of the spray pipe are in smooth transition, the outlet of the spray pipe is almost in a square section, and the expansion angle is very small, so that the sectional area of an inner experiment area of the experiment cabin in the direct connection mode is small, the size of a model is greatly restricted during experiments, the size of the model is limited, and the experiment cabin is suitable for supersonic/hypersonic wind tunnels with small sizes. The outlet of the spray pipe of the free jet mode experiment cabin is only in transitional connection with the experiment cabin, and the spray pipe extends into the experiment cabin. The free jet mode experiment cabin has the advantages that the internal interval is large, the installation of a model part is convenient, the installation is limited by a rhombic area at the outlet of a spray pipe, the effective experiment area in the experiment cabin is small, and most of the free jet mode experiment cabin is used for a large supersonic/hypersonic wind tunnel. At present, the two modes of the experiment cabin have more application ranges and relatively mature technology.
Disclosure of Invention
The invention provides a semi-free jet experiment cabin and a wind tunnel with the same, and aims to solve the technical problems that in the existing experiment cabin, the size of a model is greatly restricted, the size of the model is limited, and the effective experiment area in the experiment cabin is smaller due to the restriction of a rhombic area at the outlet of a spray pipe.
The technical scheme adopted by the invention is as follows:
a semi-free jet experiment chamber is used for being connected with a spray pipe outlet of a spray pipe, is in a hollow tubular shape and comprises an upper chamber wall surface and a lower chamber wall surface which are arranged oppositely from top to bottom, and two chamber side wall surfaces which are respectively and vertically connected with the upper chamber wall surface and the lower chamber wall surface, wherein the upper chamber wall surface is a flat wall surface and is used for being in seamless butt joint with the spray pipe outlet and is in smooth transition connection with the upper pipe wall surface at the spray pipe outlet so as to prevent airflow from forming shock waves on the upper chamber wall surface; the cabin side wall surface is a flat wall surface and is used for seamless butt joint with the outlet of the spray pipe and is in smooth transition connection with the pipe side wall surface corresponding to the outlet of the spray pipe; the rear section of the wall surface under the cabin is recessed inwards to form a nacelle for mounting an angle mechanism so as to facilitate the mounting and posture adjustment of a test model and avoid the influence of a formed wave system on the test measurement.
Furthermore, the upper wall surface of the cabin is a flat wall surface formed by fitting data points of a long spray pipe molded line 30-50 mm in front of the outlet of the spray pipe according to the expansion wave-absorbing curve of the spray pipe.
Further, the under-cabin wall surface comprises a first lower wall plane and a lower wall concave surface for forming the nacelle; the first lower wall plane is a flat wall surface and is used for being in seamless butt joint with the outlet of the spray pipe and being in smooth transition connection with the lower wall surface of the pipe at the outlet of the spray pipe, and the first lower wall plane is used for guiding airflow and avoiding the airflow from forming a wave system on the first lower wall plane; the inflow end of the lower wall concave surface is in smooth transition connection with the first lower wall plane, and the angle mechanism is detachably connected to the lower wall concave surface.
Furthermore, the concave surface of the lower wall is an arc surface, and the arc radius of the concave surface of the lower wall is 1.5-3 times of the distance between the upper wall surface of the cabin and the plane of the first lower wall; the lower wall concave surface is located in the middle of the width direction of the lower wall surface of the cabin, and the width of the lower wall concave surface is 2/3-3/4 of the width of the lower wall surface of the cabin.
Furthermore, the lower wall surface of the cabin also comprises a second lower wall plane which is a flat wall surface, the second lower wall plane is in smooth transition connection with the outflow end of the lower wall concave surface, and the second lower wall plane is used for guiding the airflow and avoiding the airflow from forming a wave system thereon.
Furthermore, the first lower wall plane and the second lower wall plane are both flat wall surfaces formed by fitting data points of a long spray pipe molded line 30-50 mm in front of the spray pipe outlet according to the expansion wave-absorbing curve of the spray pipe.
Furthermore, a plurality of optical observation windows for observing the flow mechanism and the structural characteristics of the mixed layer flow field in the experiment chamber are arranged on the side wall of the experiment chamber; the lower wall concave surface is arranged corresponding to the optical observation window; the length of the first lower wall plane along the airflow flowing direction is 1/6-1/5 of the length of the wall surface under the cabin; the length of the second lower wall plane along the airflow flowing direction is 1/10-1/6 of the length of the wall surface under the cabin.
Furthermore, a plurality of first connecting lugs are arranged on the outer wall surface of the outlet of the spray pipe at intervals in sequence along the circumferential direction; the outer wall of the inflow end of the experiment chamber is provided with second connecting lugs which are matched with the first connecting lugs one by one, and the experiment chamber is detachably connected with the spray pipe through a connecting piece which penetrates through the second connecting lugs and the first connecting lugs.
According to another aspect of the present invention, there is also provided a wind tunnel comprising: a nozzle for accelerating the airflow to a required Mach number and then spraying out, the experiment chamber of any one of claims 1 to 8 detachably connected with the nozzle outlet of the nozzle, and a diffuser pipe detachably connected with the experiment chamber outlet of the experiment chamber and used for discharging the airflow after decelerating and pressurizing.
Further, the diffuser pipe is matched with the outlet of the experiment cabin.
The invention has the following beneficial effects:
in the semi-free jet experiment cabin, the upper wall surface of the cabin is a flat wall surface and is used for being in seamless butt joint with the outlet of the spray pipe and being in smooth transition connection with the upper wall surface of the pipe at the outlet of the spray pipe so as to prevent airflow from forming shock waves on the upper wall surface of the cabin and further avoid generating interference and influence on a flow field test area in the experiment cabin, so that a uniform and stable flow field is formed on the upper wall surface of the cabin, and the research on the flow field structure of a supersonic/hypersonic mixed layer is facilitated; the rear section of the lower wall surface of the cabin is recessed inwards to form a nacelle, so that on one hand, the area of a flow field test area in the test cabin is increased, the installation and the posture adjustment of an angle mechanism on a test model are facilitated, on the other hand, a wave system does not appear on the lower wall surface of the cabin immediately, but appears on the nacelle section, but the wave system appearing on the nacelle section is mainly distributed at the downstream of the test model because the nacelle is positioned at the downstream section of the lower wall surface of the cabin, and further, the influence of the wave system on the test measurement is avoided; the semi-free jet experiment chamber is designed by the matching structure of the upper wall surface and the lower wall surface of the chamber, so that the experiment chamber integrating a direct connection mode and a free jet mode is formed, a rhombic area does not exist in the experiment chamber, the influence of a wave system in a flow field on a boundary layer is effectively reduced, the limitation of the size of an effective flow field test area of the experiment chamber to the size of the rhombic area is avoided, the area of the effective flow field test area in the experiment chamber is large, the installation and posture adjustment of an experiment model and the implementation of related experiment technologies are facilitated, the restriction of the size of the experiment model during the experiment is reduced on the premise of ensuring the area of the effective flow field test area, the size of the experiment model is increased, and the experimental research of a fine structure of the boundary layer, pneumatic optics and;
the wind tunnel can prevent the airflow from forming shock waves on the upper wall surface of the cabin, further avoid interference and influence on a flow field test area in the experimental cabin, form a uniform and stable flow field on the upper wall surface of the cabin, and facilitate the research on the flow field structure of the supersonic/hypersonic mixed layer; meanwhile, the area of a flow field test area in the experiment chamber can be increased, the installation and the posture adjustment of an angle mechanism on the experiment model are convenient, and the influence of a wave system on the experiment measurement is avoided; the wind tunnel provided by the invention has the advantages that the rhombic area does not exist in the experiment cabin, the influence of a wave system in a flow field on a boundary layer is effectively reduced, the limitation of the size of the rhombic area on an effective flow field test area of the experiment cabin is avoided, the area of the effective flow field test area in the experiment cabin is large, the installation, the posture adjustment and the implementation of related experiment technologies of a test model are facilitated, the restriction of the size of the test model during the experiment is reduced on the premise of ensuring the area of the effective flow field test area, the size of the test model is increased, and the experimental research on a fine structure of the boundary layer, the pneumatic optics and the like is facilitated.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic cross-sectional view of a semi-free jet experimental chamber according to a preferred embodiment of the present invention.
Description of the figures
10. A nozzle; 101. a nozzle outlet; 103. the lower wall surface of the pipe; 104. a tube side wall surface; 20. an experiment cabin; 201. the upper wall surface of the cabin; 202. the lower wall surface of the cabin; 2021. a first lower wall plane; 2022. a lower wall concave surface; 2023. a second lower wall plane; 203. a cabin side wall face; 30. an angle mechanism; 40. an optical viewing window; 50. a first connecting lug; 60. a second connecting lug; 70. a diffuser pipe.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the accompanying drawings, but the invention can be embodied in many different forms, which are defined and covered by the following description.
Referring to fig. 1, the preferred embodiment of the present invention provides a semi-free jet experimental chamber for connecting with the nozzle outlet 101 of the nozzle 10, wherein the experimental chamber 20 is hollow and tubular, and comprises an upper chamber wall 201 and a lower chamber wall 202 which are arranged opposite to each other from top to bottom, and two chamber wall surfaces 203 which are respectively and vertically connected with the upper chamber wall 201 and the lower chamber wall 202, wherein the upper chamber wall 201 is a flat wall surface and is used for being in seamless butt joint with the nozzle outlet 101 and being in smooth transition connection with the upper tube wall at the nozzle outlet 101 to prevent the air flow from forming shock waves on the upper chamber wall 201. The cabin side wall surface 203 is a flat wall surface for seamless abutment with the nozzle outlet 101 and smooth transition connection with the corresponding pipe side wall surface 104 at the nozzle outlet 101. The rear section of the cabin lower wall surface 202 is recessed to form a pod for mounting the angle mechanism 30 for installation and attitude adjustment of the test model and to avoid the influence of the formed wave system on the test measurement.
In the semi-free jet experiment chamber, the upper wall surface 201 of the chamber is a flat wall surface and is used for being in seamless butt joint with the outlet 101 of the spray pipe and being in smooth transition connection with the upper wall surface of the pipe at the outlet 101 of the spray pipe so as to prevent airflow from forming shock waves on the upper wall surface 201 of the chamber and further avoid generating interference and influence on a flow field test area in the experiment chamber 20, so that a uniform and stable flow field is formed at the upper wall surface 201 of the chamber, and the research on the structure of a flow field of a supersonic/hypersonic mixed layer is facilitated; the rear section of the lower cabin wall surface 202 is recessed inwards to form a pod, so that on one hand, the area of a flow field test area in the test cabin is increased, the installation and the posture adjustment of the angle mechanism 30 on a test model are facilitated, on the other hand, the wave system does not appear on the lower cabin wall surface 202 immediately, but appears on the pod section, but the wave system appearing on the pod section is mainly distributed on the downstream of the test model because the pod is positioned on the downstream section of the lower cabin wall surface 202, and further, the influence of the wave system on the test measurement is avoided; the semi-free jet experiment chamber of the invention forms the experiment chamber 20 integrating the direct connection mode and the free jet mode through the matching structure design of the upper chamber wall surface 201 and the lower chamber wall surface 202, so that a rhombic area does not exist in the experiment chamber 20, the influence of a wave system in a flow field on a boundary layer is effectively reduced, the limitation of the size of an effective flow field test area of the experiment chamber 20 by the size of the rhombic area is avoided, the area of the effective flow field test area in the experiment chamber is large, the installation and posture adjustment of an experiment model and the implementation of related experiment technologies are facilitated, and the restriction of the size of the experiment model during the experiment is reduced on the premise of ensuring the area of the effective flow field test area, so that the size of the experiment model is increased, and the experimental research on a fine boundary layer structure, pneumatic optics and.
Alternatively, as shown in fig. 1, the cabin upper wall surface 201 is a flat wall surface formed by fitting data points of a long nozzle profile 30mm to 50mm in front of the nozzle outlet 101 according to the expansion wave-absorbing curve of the nozzle 10. Specifically, when the upper wall surface 201 of the cabin is designed, according to an expansion wave-absorbing curve of the nozzle 10, a data point of a long nozzle molded line 30mm to 50mm in front of the nozzle outlet 101 is taken, a data point gradient is obtained through fitting, the upper wall surface 201 of the cabin continues to extend along with the gradient, the upper wall surface 201 of the cabin is in seamless butt joint with the nozzle outlet 101 of the nozzle, the air flow is prevented from forming shock waves on the upper wall surface 201 of the cabin, interference and influence on a flow field test area in the experiment cabin 20 are further avoided, a uniform and stable flow field is formed on the upper wall surface 201 of the cabin, and the research on the flow field structure of the supersonic.
Optionally, as shown in fig. 1, the two cabin side wall surfaces 203 are flat wall surfaces parallel to each other, and are used for being in seamless butt joint with the nozzle outlet 101 and being in smooth transition connection with the corresponding pipe side wall surface 104 at the nozzle outlet 101 so as to prevent the airflow from forming shock waves on the cabin side wall surfaces 203, and further avoid generating interference and influence on the flow field test area in the experimental cabin 20.
Alternatively, as shown in fig. 1, the under-cabin wall 202 includes a first lower wall plane 2021 and a lower wall concavity 2022 for forming a nacelle. The first lower wall plane 2021 is a flat wall surface for seamless interfacing with the nozzle outlet 101 and smoothly transitionally connecting with the lower tube wall surface 103 at the nozzle outlet 101, and the first lower wall plane 2021 is for guiding the air flow and preventing the air flow from forming a wave train thereon. The inflow end of the lower wall concave surface 2022 is smoothly and transitionally connected with the first lower wall plane 2021, and the angle mechanism 30 is detachably connected to the lower wall concave surface 2022. The structural design of the under-cabin wall surface 202 can increase the area of a flow field test area in the test cabin, so that the angle mechanism 30 can conveniently install and adjust the posture of the test model, and can prevent the under-cabin wall surface 202 from generating wave systems immediately, but the wave systems are generated on the lower wall concave surface 2022, but because the lower wall concave surface 2022 is positioned at the downstream section of the under-cabin wall surface 202, the wave systems generated on the lower wall concave surface 2022 are mainly distributed at the downstream of the test model, and further the wave systems are prevented from influencing the experimental measurement.
In this alternative, as shown in fig. 1, the lower wall concave surface 2022 is an arc surface, and the arc radius of the arc surface is 1.5 to 3 times the distance between the cabin upper wall surface 201 and the first lower wall plane 2021. The lower wall concave surface 2022 is an arc surface, which not only facilitates the design of the structure, but also reduces the formation of wave system compared with the surface with corner, further avoiding the interference and influence of wave system on the experimental measurement; the arc radius is 1.5-3 times of the distance between the cabin upper wall surface 201 and the first lower wall plane 2021, so that on one hand, the area of an effective flow field test area is increased, the installation, the posture adjustment and the implementation of related experiment technologies of a test model are facilitated, and on the other hand, the phenomenon that the flow of air flow in the experiment cabin 20 is influenced by the overlarge depth of the lower wall concave surface 2022 is avoided.
In this alternative, as shown in fig. 1, the lower wall concave surface 2022 is located in the middle of the width direction of the cabin lower wall surface 202, which is beneficial to guiding the airflow by the cabin lower wall surface 202 on both sides of the width direction of the lower wall concave surface 2022; and the width of the concave surface 2022 of the lower wall is 2/3-3/4 of the width of the lower wall surface 202 of the cabin, so that the required area for installation in the width direction of the angle mechanism 30 is ensured, and the guiding of the airflow by the lower wall surface 202 of the cabin on both sides of the concave surface 2022 of the lower wall in the width direction is facilitated.
Optionally, as shown in fig. 1, the under-cabin wall surface 202 further includes a second lower wall plane 2023, the second lower wall plane 2023 is a flat wall surface, the second lower wall plane 2023 is smoothly and transitionally connected with the outflow end of the lower wall concave surface 2022, and the second lower wall plane 2023 is used for guiding the airflow and preventing the airflow from forming a wave system thereon.
In this alternative, as shown in fig. 1, the first lower wall plane 2021 and the second lower wall plane 2023 are both flat wall surfaces formed by fitting data points of a model line of the long nozzle 10, which is 30mm to 50mm in front of the nozzle outlet 101, according to the expansion wave-absorbing curve of the nozzle 10. Specifically, when the first lower wall plane 2021 and the second lower wall plane 2023 are designed, according to the expansion wave-absorbing curve of the nozzle 10, data points of a 30mm to 50mm long nozzle molded line in front of the nozzle outlet 101 are taken, a gradient of the data points is obtained through fitting, and the first lower wall plane 2021 and the second lower wall plane 2023 continue to extend along with the gradient, so that the first lower wall plane 2021 is in smooth transition connection with the lower wall surface 103 of the nozzle outlet 101, and the second lower wall plane 2023 is in smooth transition connection with the outflow end of the lower wall concave surface 2022, thereby preventing the air flow from forming shock waves on the first lower wall plane 2021 and the second lower wall plane 2023, and further avoiding generating interference and influence on the flow field test area in the experimental cabin 20.
Optionally, as shown in fig. 1, a plurality of optical observation windows 40 for observing the flow mechanism and structural characteristics of the mixed layer flow field inside the experiment chamber 20 are arranged on the side wall of the experiment chamber 20. The concave surface 2022 of the lower wall is disposed corresponding to the optical observation window 40, so that the flow mechanism and the structural characteristics of the mixed layer flow field inside the experiment chamber 20 can be observed through the optical observation window 40. Specifically, two optical observation windows 40 are respectively arranged on the side wall corresponding to the cabin upper wall surface 201 and the side walls corresponding to the two cabin side wall surfaces 203, and the optical observation windows 40 are square and are sequentially arranged at intervals along the length direction of the experiment cabin 20. The length of the first lower wall plane 2021 in the airflow flowing direction is 1/6-1/5 of the length of the cabin lower wall surface 202, and the first lower wall plane has enough length to guide airflow and simultaneously prevent the excessive length from influencing the installation of a subsequent test model. The length of the second lower wall plane 2023 in the airflow flowing direction is 1/10-1/6 of the length of the cabin lower wall surface 202, the length of the lower wall concave surface 2022 can be prolonged as far as possible while the length of the second lower wall plane 2023 is enough to guide the airflow, the effective flow field test area in the experiment cabin is increased, the restriction on the size of the experiment model during the experiment is reduced, the size of the experiment model is increased, and the experimental research on boundary layer fine structures, pneumatic optics and the like is facilitated.
Alternatively, as shown in fig. 1, the outer wall surface of the nozzle outlet 101 is provided with a plurality of first connecting lugs 50 arranged at intervals in the circumferential direction. The outer wall surface of the inflow end of the experiment chamber 20 is provided with second connecting lugs 60 which are matched with the first connecting lugs 50 one by one, and the experiment chamber 20 is detachably connected with the spray pipe 10 through a connecting piece which passes through the second connecting lugs 60 and the first connecting lugs 50. In particular, the connecting members are connecting screws or connecting bolts, and the connection operation of the experiment chamber 20 and the nozzle 10 is simple and convenient to implement.
Referring to fig. 1, a preferred embodiment of the present invention also provides a wind tunnel including: the experiment chamber comprises a spray pipe 10 for spraying the airflow after accelerating the airflow to the required Mach number, the experiment chamber 20 which is detachably connected with a spray pipe outlet 101 of the spray pipe 10 and is provided with any one of the above, and a diffuser pipe 70 which is detachably connected with an experiment chamber outlet of the experiment chamber 20 and is used for discharging the airflow after decelerating and pressurizing the airflow. In the wind tunnel structure, the experiment cabin 20 is connected between the spray pipe 10 and the diffuser pipe 70, so that the wind tunnel can prevent airflow from forming shock waves on the upper wall surface 201 of the cabin, further avoid interference and influence on a flow field test area in the experiment cabin 20, form a uniform and stable flow field on the upper wall surface 201 of the cabin, and facilitate research on the flow field structure of the supersonic/hypersonic mixed layer; meanwhile, the area of a flow field test area in the test chamber can be increased, the installation and the posture adjustment of the angle mechanism 30 on the test model are convenient, and the influence of wave systems on the test measurement is avoided; the wind tunnel of the invention has the advantages that the rhombic area does not exist in the experiment chamber 20, the influence of wave systems in a flow field on a boundary layer is effectively reduced, the limitation of the size of the rhombic area on an effective flow field test area of the experiment chamber 20 is avoided, the area of the effective flow field test area in the experiment chamber is large, the installation, the posture adjustment and the implementation of related experiment technologies of the experiment model are convenient, the restriction of the size of the experiment model during the experiment is reduced on the premise of ensuring the area of the effective flow field test area, the size of the experiment model is increased, and the experimental research of a fine structure of the boundary layer, the pneumatic optics and the like is favorably carried out.
Alternatively, as shown in FIG. 1, a diffuser tube 70 is provided in cooperation with the outlet of the experimental chamber 20. Specifically, the diffuser pipe 70 is in a hollow tubular shape, and includes an upper wall surface and a lower wall surface which are arranged oppositely from top to bottom, and two side wall surfaces which are respectively vertically connected with the upper wall surface and the lower wall surface, wherein the upper wall surface is a flat wall surface and is used for being in seamless butt joint with the outlet of the experiment chamber and being in smooth transition connection with the upper chamber wall surface 201 at the outlet of the experiment chamber. The side wall surface is a flat wall surface and is used for seamless butt joint with the outlet of the experiment chamber and is in smooth transition connection with the corresponding chamber side wall surface 203 at the outlet of the experiment chamber. When the diffuser pipe 70 is actually designed, the size of the test model is increased after the test chamber is designed, so that the normal start of the wind tunnel is ensured on the premise that the test model meets the blockage ratio by the design of the diffuser pipe 70.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A semi-free jet experiment chamber is used for being connected with a jet pipe outlet (101) of a jet pipe (10), the experiment chamber (20) is in a hollow tubular shape and comprises an upper chamber wall surface (201) and a lower chamber wall surface (202) which are oppositely arranged up and down, and two chamber side wall surfaces (203) which are respectively and vertically connected with the upper chamber wall surface (201) and the lower chamber wall surface (202),
the upper cabin wall surface (201) is a flat wall surface and is used for being in seamless butt joint with the spray pipe outlet (101) and being in smooth transition connection with the upper pipe wall surface at the spray pipe outlet (101) so as to prevent airflow from forming shock waves on the upper cabin wall surface (201);
the cabin side wall surface (203) is a flat wall surface and is used for being in seamless butt joint with the spray pipe outlet (101) and being in smooth transition connection with a pipe side wall surface (104) corresponding to the spray pipe outlet (101);
the rear section of the under-cabin wall surface (202) is recessed inwards to form a nacelle for mounting an angle mechanism (30) so as to facilitate the mounting and posture adjustment of a test model and avoid the influence of a formed wave system on the test measurement;
the upper wall surface (201) of the cabin is a flat wall surface formed by fitting data points of a long spray pipe molded line 30-50 mm in front of the spray pipe outlet (101) according to an expansion wave absorption curve of the spray pipe (10); when the upper wall surface (201) of the cabin is designed, according to an expansion wave-absorbing curve of the spray pipe (10), data points of the molded line of the long spray pipe 30-50 mm in front of the spray pipe outlet (101) are taken, a data point gradient is obtained through fitting, the upper wall surface (201) of the cabin extends along with the gradient, the upper wall surface (201) of the cabin is in seamless butt joint with the spray pipe outlet (101), shock waves of airflow on the upper wall surface (201) of the cabin are avoided, interference and influence on a flow field test area in the experimental cabin (20) are avoided, a uniform and stable flow field is formed at the upper wall surface (201) of the cabin, and research on a flow field structure of an ultrasonic velocity/hypersonic velocity mixed layer is.
2. The semi-free jet experimental chamber of claim 1,
the under-cabin wall (202) comprising a first lower wall plane (2021) and a lower wall concavity (2022) for forming the nacelle;
the first lower wall plane (2021) is a flat wall surface and is used for being in seamless butt joint with the spray pipe outlet (101) and being in smooth transition connection with the lower pipe wall surface (103) at the spray pipe outlet (101), and the first lower wall plane (2021) is used for guiding airflow and avoiding the airflow from forming wave series on the airflow;
the inflow end of the lower wall concave surface (2022) is in smooth transition connection with the first lower wall plane (2021), and the angle mechanism (30) is detachably connected to the lower wall concave surface (2022).
3. The semi-free jet experimental chamber of claim 2,
the lower wall concave surface (2022) is an arc surface, and the arc radius of the lower wall concave surface is 1.5-3 times of the distance between the cabin upper wall surface (201) and the first lower wall plane (2021);
the lower wall concave surface (2022) is located in the middle of the width direction of the cabin lower wall surface (202), and the width of the lower wall concave surface (2022) is 2/3-3/4 of the width of the cabin lower wall surface (202).
4. The semi-free jet experimental chamber of claim 2,
the cabin lower wall surface (202) further comprises a second lower wall plane (2023), the second lower wall plane (2023) is a flat wall surface, the second lower wall plane (2023) is in smooth transition connection with the outflow end of the lower wall concave surface (2022), and the second lower wall plane (2023) is used for guiding the airflow and avoiding the airflow from forming a wave system thereon.
5. The semi-free jet experimental chamber of claim 4,
the first lower wall plane (2021) and the second lower wall plane (2023) are both flat wall surfaces formed by fitting data points of a long nozzle molded line 30-50 mm in front of the nozzle outlet (101) according to an expansion wave-absorbing curve of the nozzle (10).
6. The semi-free jet experimental chamber of claim 4,
a plurality of optical observation windows (40) for observing the flow mechanism and the structural characteristics of the mixed layer flow field in the experiment chamber (20) are arranged on the side wall of the experiment chamber (20);
the lower wall concave surface (2022) is arranged corresponding to the optical observation window (40);
the length of the first lower wall plane (2021) in the airflow flowing direction is 1/6-1/5 of the length of the cabin lower wall surface (202);
the length of the second lower wall plane (2023) in the airflow flowing direction is 1/10-1/6 of the length of the under-cabin wall surface (202).
7. The semi-free jet experimental chamber of claim 1,
a plurality of first connecting lugs (50) which are sequentially arranged at intervals along the circumferential direction are arranged on the outer wall surface of the spray pipe outlet (101);
the outer wall of the inflow end of the experiment chamber (20) is provided with a plurality of second connecting lugs (60) which are matched with the first connecting lugs (50) one by one, and the experiment chamber (20) is detachably connected with the spray pipe (10) through a connecting piece which penetrates through the second connecting lugs (60) and the first connecting lugs (50).
8. A wind tunnel, comprising:
a nozzle (10) for accelerating the gas flow to a desired Mach number and then discharging the gas flow, a test chamber (20) according to any one of claims 1 to 7 detachably connected to a nozzle outlet (101) of the nozzle (10), and a diffuser (70) detachably connected to the test chamber outlet of the test chamber (20) and adapted to discharge the gas flow after being decelerated and pressurized.
9. A wind tunnel according to claim 8,
the diffuser pipe (70) is matched with the outlet of the experiment cabin.
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