CN213336715U - Lifting type large-view-field schlieren instrument - Google Patents

Abstract

The utility model discloses a big visual field schlieren of over-and-under type appearance, this schlieren appearance includes base, elevating system, braced frame, camera, edge of a knife and parabolic mirror, elevating system sets up the both ends at the base, braced frame's both ends horizontal mount is established on elevating system, braced frame's one end sets up optics fixed plate, camera and edge of a knife are established on optics fixed plate through first XY elevating platform, second XY elevating platform respectively, one side of the second XY elevating platform that has set up the edge of a knife is equipped with the pointolite, parabolic mirror passes through mirror surface mount to be fixed in the picture frame, the picture frame is vertical to be fixed at braced frame's the other end; wherein the knife edge is positioned between the camera and the parabolic reflector, and the camera, the knife edge and the parabolic reflector are on the same straight line; a candlestick is arranged on the base between the knife edge and the parabolic reflector and close to one end of the parabolic reflector. The schlieren instrument has simple structure and low cost, and can obtain schlieren images with large view field by adopting a paraboloidal reflector with small caliber.

Description

Lifting type large-view-field schlieren instrument

Technical Field

The utility model relates to a schlieren appearance technical field specifically is a big visual field schlieren appearance of over-and-under type.

Background

Schlieren is a non-contact optical measurement technique for transparent media flow fields. The schlieren principle test dates back to the 17 th century, and people change any airflow which is invisible to surface observation into a visible airflow through a knife edge experiment. In the 20 th century, schlieren technology became an important tool in the hydrodynamics laboratory. With the rapid development of the aviation industry, the urgent need for large schlieren equipment is gradually reflected. There are numerous potential applications for a schlieren system that can accommodate full-size equipment and personnel.

The optical facility size for large industrial wind tunnels typically ranges from 0.4m to 0.75 m. In a schlieren system, the larger the field of view, the larger the required parabolic mirror area. The traditional schlieren system usually needs to install a large-caliber parabolic reflector, is limited by an optical processing technology, and has very high processing cost and harsh experimental conditions.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art's is not enough, and provide a big visual field schlieren appearance of over-and-under type, this schlieren appearance simple structure, it is with low costs, adopt the parabolic reflecting mirror of small bore, just can obtain big visual field schlieren image.

Realize the utility model discloses the technical scheme of purpose is:

a lifting type large-view-field schlieren instrument comprises a base, a lifting mechanism, a supporting frame, a camera, a knife edge and a parabolic reflector, wherein the lifting mechanism is respectively arranged at two ends of the base; wherein the knife edge is positioned between the camera and the parabolic reflector, and the camera, the knife edge and the parabolic reflector are on the same straight line; a candlestick is arranged on the base between the knife edge and the parabolic reflector and close to one end of the parabolic reflector.

And angle sensors are arranged around the supporting frame and connected with the controller.

The lifting mechanism comprises a stepping motor, a first lead screw lifter and a second lead screw lifter, the stepping motor is connected with the controller, an output shaft of the stepping motor is connected with one end of a transmission shaft of the first lead screw lifter, and the other end of the transmission shaft of the first lead screw lifter is connected with a transmission shaft of the second lead screw lifter through a coupler; the upper ends of the lifting screw rods of the first screw rod lifter and the second screw rod lifter are connected with the supporting frame, and the lower ends of the lifting screw rods can penetrate through the base to lift.

The lifting mechanism has the maximum lifting height of 450 mm.

The focal length of the parabolic reflector is 750 mm.

The knife edge is positioned at about 1450-1550mm right in front of the parabolic reflector.

The use method of the lifting type large-view-field schlieren instrument comprises the following steps:

1) vertically fixing a mirror frame provided with a parabolic reflector on a support frame, adjusting a base to enable the upper surface of a base to be horizontal and stable, adjusting lifting screw rods of a first screw rod lifter and a second screw rod lifter, and ensuring that the upper end surfaces of the lifting screw rods on each side are at the same height;

2) opening power switches of an angle sensor and a controller, sending inclination angle data to the controller by the angle sensor on the supporting frame, sending a signal to a stepping motor by the controller according to the inclination angle data, and driving a screw rod lifter by the stepping motor to enable the upper end surfaces of lifting screw rods of the screw rod lifters at the two ends of the base to be at the same height;

3) opening a point light source, enabling a circular light spot to appear near a knife edge, adjusting a first XY lifting table to enable the circular light spot to be minimum, and enabling the knife edge to divide the light spot into two parts;

4) adjusting a second XY lifting table to enable an aperture of the camera to align to a light spot at the position of the knife edge, and adjusting parameters of the camera to enable a bright and clear mirror image to be observed in a viewfinder of the camera;

5) placing a flow field to be detected on a candlestick, adjusting a lifting screw rod through a stepping motor after the flow field to be detected is stable, enabling the lifting screw rod to be located at the lowest position, shooting a first picture by a camera, simultaneously controlling the stepping motor, enabling a lifting mechanism to drive a supporting frame to rise horizontally at a constant speed of 5mm/s, exposing a picture by the camera every 1 second, and outputting a first synthetic schlieren picture after the lifting mechanism rises to the highest lift;

6) controlling a stepping motor to enable a lifting mechanism to drive a supporting frame to descend horizontally at a constant speed of 5mm/s, exposing a picture by a camera at an interval of 1 second, and outputting a second synthesized schlieren picture by the camera after the lifting mechanism descends to the lowest position;

7) and after the experiment is finished, removing the flow field to be detected on the candlestick, closing the power supply and waiting for the next experiment.

The utility model provides a lifting type large-view-field schlieren instrument and a use method thereof, the schlieren instrument is characterized in that two groups of lifting mechanisms are arranged at two ends of a supporting frame, each group is respectively composed of a stepping motor and two lead screw lifters, and the problem that the aluminum profile frame is difficult to ensure to be horizontal through a mechanical transmission single-power lifting mechanism is avoided; the angle sensors are respectively arranged on the periphery of the supporting frame, and the movement of the two groups of lifting mechanisms is controlled through the feedback of electric signals, so that the optical part is kept horizontal during working. The knife edge and the camera are both arranged on the XY-axis lifting table, and the relative positions of the optical components can be controlled through fine adjustment when the optical path is arranged, so that the installation difficulty of the optical equipment is reduced. The optical part of the schlieren instrument can move up and down through the lifting mechanism, and multiple shots of a flow field in the vertical direction are realized. Two large-view-field schlieren images in the vertical direction can be generated in each experiment, and compared with a parabolic reflector with an equivalent caliber, the cost is greatly reduced.

Drawings

FIG. 1 is a schematic structural diagram of a lift type large-field schlieren instrument;

FIG. 2 is a schematic view of the knife edge and camera mounted on the optical mounting plate;

FIG. 3 is a schematic structural view of the lifting mechanism;

FIG. 4 is a cross-sectional view of the lift mechanism;

in the figure: 1. the base 2, the candlestick 3, the supporting frame 4, the mirror frame 5, the parabolic reflector 6, the lifting mechanism 7, the camera 8, the knife edge 9, the angle sensor 10, the optical fixing plate 11, the point light source 12, the second XY lifting table 13, the first XY lifting table 14, the stepping motor 15, the first lead screw lifter 16, the lifting lead screw 17, the transmission shaft 18, the coupler 19, the second lead screw lifter 20, the base opening 21 and the base hollow pillar.

Detailed Description

The present invention will be further explained with reference to the drawings and examples, but the present invention is not limited thereto.

As shown in fig. 1 and 2, a lifting type large-view-field schlieren instrument comprises a base 1, a lifting mechanism 6, a supporting frame 3, a camera 7, a knife edge 8 and a parabolic reflector 5, wherein the lifting mechanism 6 is respectively arranged at two ends of the base 1, horizontal fixing frames at two ends of the supporting frame 3 are arranged on the lifting mechanism 6, one end of the supporting frame 3 is provided with an optical fixing plate 10, the camera 7 and the knife edge 8 are respectively arranged on the optical fixing plate 10 through a first XY lifting table 13 and a second XY lifting table 12, one side of the second XY lifting table 12 provided with the knife edge 8 is provided with a point light source 11, the parabolic reflector 5 is fixed in a mirror frame 4 through a mirror surface fixing frame, and the mirror frame 4 is vertically fixed at the other end of the supporting; wherein the knife edge 8 is positioned between the camera 7 and the parabolic reflector 5, and the camera 7, the knife edge 8 and the parabolic reflector 5 are on the same straight line; a candlestick 2 is arranged on the base 1 between the knife edge 8 and the parabolic reflector 5 and close to one end of the parabolic reflector 5.

And angle sensors 9 are arranged around the supporting frame 3, and the angle sensors 9 are connected with a controller.

The lifting mechanism 6 comprises a stepping motor 14, a first lead screw lifter 15 and a second lead screw lifter 19, wherein the stepping motor 14 is connected with the controller, an output shaft of the stepping motor 14 is connected with one end of a transmission shaft 17 of the first lead screw lifter 15, and the other end of the transmission shaft 17 of the first lead screw lifter 15 is connected with a transmission shaft of the second lead screw lifter 19 through a coupler 18; the upper ends of the lifting screw rods 16 of the first screw rod lifter 15 and the second screw rod lifter 19 are connected with the supporting frame 3, and the lower ends can penetrate through the open holes 20 arranged on the base 1 and extend into the hollow support 21 of the base 1 for lifting.

The lifting mechanism 6 has the maximum lifting height of 450 mm.

The focal length of the parabolic reflector 5 is 750 mm.

The knife edge 8 is positioned at the position of about 1500mm right in front of the parabolic reflector 5.

The use method of the lifting type large-view-field schlieren instrument comprises the following steps:

1) vertically fixing a mirror frame 4 provided with a parabolic reflector 5 on a support frame 3, adjusting a base 1 to enable the upper surface of a base 2 to be horizontal and stable, adjusting lifting screw rods 16 of a first screw rod lifter 15 and a second screw rod lifter 19, and ensuring that the upper end surfaces of the lifting screw rods 16 on each side are at the same height;

2) opening power switches of an angle sensor 9 and a controller, sending inclination angle data to the controller by the angle sensor 9 on the supporting frame 3, sending a signal to a stepping motor 14 by the controller according to the inclination angle data, and driving a screw rod lifter by the stepping motor 14 to enable the upper end surfaces of lifting screw rods 16 of the screw rod lifters at the two ends of the base 1 to be at the same height;

3) opening the point light source 11, generating a circular light spot near the knife edge 8, and adjusting the first XY lifting table 13 to minimize the circular light spot and divide the light spot into two by the knife edge 8;

4) adjusting a second XY lifting table 12 to enable the aperture of the camera 7 to be aligned to the light spot at the knife edge 8, and adjusting parameters of the camera 7 to enable a bright and clear mirror image to be observed in a viewfinder of the camera 7;

at this time, a switch controlled by the lifting mechanism 6 can be started, whether the stepping motor 14, the first screw rod lifter and the second screw rod lifter operate normally or not is further determined, and whether the supporting frame 3 keeps balance or not in the lifting process is detected through the level gauge; the coaxiality of the output shaft of the stepping motor 14, the transmission shaft 17 and the coupling 18 of the screw rod lifter is ensured, and the shaking is reduced. The coaxiality of the lifting screw rod 16, the opening 20 on the base and the hollow upright post 21 is ensured, and the smooth lifting of the screw rod is kept.

5) Placing a flow field to be detected on a candlestick 2, after the flow field to be detected is stable, adjusting a lifting screw rod 16 through a stepping motor 14 to enable the lifting screw rod 16 to be positioned at the lowest position, shooting a first picture by a camera 7, simultaneously controlling the stepping motor 14 to enable a lifting mechanism 6 to drive a supporting frame 3 to horizontally rise at a constant speed of 5mm/s, exposing the picture by the camera 7 every 1 second, and outputting a first synthetic schlieren picture after the lifting mechanism 6 rises to the highest lift;

6) controlling a stepping motor 14 to enable a lifting mechanism 6 to drive a support frame 7 to descend horizontally at a constant speed of 5mm/s, exposing a photo by a camera 7 at intervals of 1 second, and outputting a second synthesized schlieren photo by the camera after the lifting mechanism 6 descends to the lowest position;

7) after the experiment is finished, the flow field to be detected on the candlestick 2 is removed, the power supply is closed, and the next experiment is waited.

Claims (6)

1. A lifting type large-view-field schlieren instrument is characterized by comprising a base, a lifting mechanism, a supporting frame, a camera, a knife edge and a parabolic reflector, wherein the lifting mechanism is respectively arranged at two ends of the base; wherein the knife edge is positioned between the camera and the parabolic reflector, and the camera, the knife edge and the parabolic reflector are on the same straight line; a candlestick is arranged on the base between the knife edge and the parabolic reflector and close to one end of the parabolic reflector.

2. The elevating large-visual-field schlieren instrument according to claim 1, wherein the supporting frame is provided with angle sensors around the supporting frame, and the angle sensors are connected with the controller.

3. The lifting type large-view-field schlieren instrument as claimed in claim 1, wherein the lifting mechanism comprises a stepping motor, a first lead screw lifter and a second lead screw lifter, the stepping motor is connected with the controller, an output shaft of the stepping motor is connected with one end of a transmission shaft of the first lead screw lifter, and the other end of the transmission shaft of the first lead screw lifter is connected with a transmission shaft of the second lead screw lifter through a coupler; the upper ends of the lifting screw rods of the first screw rod lifter and the second screw rod lifter are connected with the supporting frame, and the lower ends of the lifting screw rods can penetrate through the base to lift.

4. The elevating large-field schlieren instrument according to claim 1, wherein the maximum height of the elevating mechanism is 450 mm.

5. The elevating large-field schlieren instrument according to claim 1, wherein the focal length of the parabolic reflector is 750 mm.

6. The elevating large-field schlieren instrument as claimed in claim 1, wherein the knife edge is located at 1450-1550mm right in front of the parabolic reflector.

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