A wind tunnel testing apparatus and method for simulating the rearward ejection of suspended objects from an aircraft.

Abstract

This invention discloses a wind tunnel test device for simulating the rearward ejection of a suspended object from an aircraft. It includes an ejection cylinder (1), an ejection piston (2) slidably connected axially within the ejection cylinder (1), an ejection air inlet (3) at the head end of the ejection cylinder (1), and the ejection piston (2) connected to the suspended object (4) and locked together via a locking mechanism (5). This invention features a simple structure, convenient and flexible speed and angular velocity adjustment, good repeatability, high reliability, and easy installation.

Description

Technical Field

[0001] This invention belongs to the field of aircraft wind tunnel testing technology, and specifically relates to a wind tunnel testing device and method for simulating the rearward ejection of suspended objects from an aircraft. Background Technology

[0002] Free-drop wind tunnel testing is a specialized type of wind tunnel test. Unlike conventional wind tunnel tests, which require fixing the model within the wind tunnel flow field and measuring aerodynamic forces using a balance, free-drop models can move freely within the wind tunnel flow field. Under the influence of aerodynamic forces and gravity, the model moves along a trajectory that obeys the laws of physics. Trajectory changes can be obtained using optical measurement methods, and analyzing this data reveals the changes in aerodynamic forces acting on the model. Free-drop wind tunnel testing most closely resembles real-world flight drops, effectively simulating unsteady aerodynamic characteristics.

[0003] To achieve a high lift-to-drag ratio, aircraft typically mount suspended objects (SPOs) in the aircraft's belly compartment. During deployment, the belly compartment door is opened from the side, and an ejection rack launches the SPO from a direction perpendicular to the aircraft's axis. This method creates a typical cavity flow after the door opens; this flow is complex and has no unique solution, significantly interfering with flight stability and the SPO's trajectory. If the SPO is mounted in a launch tube, during launch, only a small angle needs to be rotated so that the rear launch tube opening is fully exposed above the fuselage plane. This allows the SPO to be launched along the launch tube axis in the opposite direction of flight. After exiting the tube, the SPO needs a nose-down angular velocity to ensure safe deployment. This method avoids the adverse effects of the cavity effect on deployment.

[0004] This rearward ejection method for launching suspended objects involves rapid and complex aerodynamic changes during the launch process, with unsteady aerodynamic forces playing a dominant role. To ensure the safety of the ejection launch, it is necessary to conduct free-launch wind tunnel tests and study the feasibility and safety of separation, as well as the impact of various factors on the safety of launch and separation. Summary of the Invention

[0005] The purpose of this invention is to provide a wind tunnel testing device and method for simulating the rearward ejection of suspended objects from an aircraft. This invention features a simple structure, convenient and flexible speed and angular velocity adjustment, good repeatability, high reliability, and easy installation.

[0006] The technical solution of the present invention is a wind tunnel test device for simulating the rearward ejection of a suspended object from an aircraft, comprising an ejection cylinder, an ejection piston slidably connected in the ejection cylinder along the axial direction, an ejection air inlet at the head end of the ejection cylinder, the ejection piston being connected to the suspended object and locked together with the ejection piston by a locking mechanism.

[0007] In the aforementioned wind tunnel test device simulating the rearward ejection of a suspended object from an aircraft, the ejection cylinder and the ejection piston are slidably connected via a guide mechanism; the guide mechanism includes a guide rail disposed on the inner wall of the ejection cylinder and a guide rail pin disposed on the ejection piston, and the guide rail pin is slidably connected to the guide rail.

[0008] In the aforementioned wind tunnel test device simulating the rearward ejection of a suspended object from an aircraft, the guide rail is provided with a blocking screw for axially limiting the guide rail pin.

[0009] In the aforementioned wind tunnel test device simulating the rearward ejection of a suspended object from an aircraft, the locking mechanism includes a locking cylinder fixed to the side wall of the ejection cylinder, a locking piston slidably connected inside the locking cylinder, the locking piston being connected to a locking pin, the locking pin passing through the side wall of the ejection cylinder and the side wall of the ejection piston in sequence before being engaged with the suspended object; a locking spring is provided between the side of the locking piston away from the locking pin and the locking cylinder, and an unlocking air inlet is provided on the side wall of the locking cylinder between the locking piston and the ejection cylinder.

[0010] In the aforementioned wind tunnel test device for simulating the rearward ejection of a suspended object from an aircraft, an angular velocity providing mechanism is provided on the side of the ejection cylinder extending in the direction of the tail end. The angular velocity providing mechanism includes an angular velocity cylinder, an angular velocity piston is slidably connected inside the angular velocity cylinder, the angular velocity piston is connected to a strike rod, the strike rod can extend out of the angular velocity cylinder, an angular velocity spring is sleeved on the strike rod, and an angular velocity air supply inlet is provided on the angular velocity cylinder.

[0011] The aforementioned method of using the wind tunnel test apparatus for simulating the rearward ejection of suspended objects from an aircraft includes the following steps:

[0012] S1. After installing the wind tunnel testing equipment on the belly of the aircraft, place it in the wind tunnel;

[0013] S2. During the wind tunnel test, once the flow field meets the requirements, the locking mechanism is unlocked, high-pressure gas is introduced into the ejection gas inlet, and the ejection piston is pushed backward to eject the suspended object into the wind tunnel flow field. The influence of each ejection parameter on the separation safety is investigated, and separation aerodynamic data is obtained.

[0014] In the aforementioned method of using the wind tunnel test device for simulating the rearward ejection of a suspended object from an aircraft, step 2, the unlocking process is as follows: air is introduced into the unlocking air inlet, pushing the locking piston to drive the locking pin back into the locking cylinder to complete the unlocking.

[0015] In the aforementioned method of using the wind tunnel test device for simulating the rearward ejection of a suspended object, in step 2, when it is necessary to provide an angle to the suspended object, when the head end of the suspended object is ejected from the ejection cylinder, the high-pressure gas at the angle and angular velocity gas supply inlet pushes the impact rod through the angular velocity piston to strike the head end of the suspended object, so that the suspended object obtains angular velocity.

[0016] The beneficial effects of this invention are:

[0017] 1. The development of a wind tunnel high-speed free-drop test equipment for a rearward ejection mechanism was achieved from scratch, enabling the key capability of simulating the rearward ejection of suspended objects by an aircraft for the first time in high-speed free-drop testing.

[0018] 2. This invention has high versatility and can meet the requirements of rearward ejection technology for various suspended object sizes and shapes;

[0019] 3. This invention is applicable to a wide range of scaled-down projectile suspension models, with a mass range of 10 to 700g, a projectile speed range of 1 to 10 m / s, an angular velocity adjustment range of 0 to 600 degrees / s, and a conveniently adjustable projectile angle (suitable for projectiles within a 90-degree backward range).

[0020] 4. As a component of a wind tunnel model, this invention can make great use of the limited space of an aircraft. Its mechanism is simple and efficient, and it can be applied to current wind tunnel test models with internal nacelles.

[0021] 5. This invention has high adjustability and wide applicability, as well as high stability. Under the same conditions of ejection pressure and action time, it can realize multiple repeated ejections of the suspended object model under the same speed and angular velocity separation conditions.

[0022] 6. This invention can achieve different speeds for launching suspended objects by adjusting the pressure of the ejection cylinder. By adjusting the action time and cylinder pressure of the angular velocity cylinder, different angular velocities can be applied to the suspended object. The structure is simple, the speed and angular velocity are easy and flexible to adjust, the repeatability is good, the reliability is high, and the installation is simple. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 This is a front sectional view of the assembly of the present invention;

[0025] Figure 3 This is a top sectional view of the assembly of the present invention;

[0026] Figure 4 A schematic diagram of the mechanism unlocking and ejection sequence;

[0027] Figure 5 This is a schematic diagram of the model's angular motion. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1. A wind tunnel testing apparatus and method for simulating the rearward ejection of a suspended object from an aircraft, see [link to example]. Figures 1-5 The invention includes an ejection cylinder 1, within which an ejection piston 2 is axially slidably connected. An ejection air inlet 3 is located at the head end of the ejection cylinder 1. The ejection piston 2 is connected to a suspended object 4 and locked together via a locking mechanism 5. This invention features a simple structure, high reliability, and can simulate ejection velocities and angular velocities at different flight altitudes and speeds. By adjusting the ejection pressure of the ejection cylinder 1, different velocities can be obtained, enabling velocity simulation of the model.

[0030] The aforementioned ejection cylinder 1 and ejection piston 2 are slidably connected via a guide mechanism 6; the guide mechanism 6 includes a guide rail 61 disposed on the inner wall of the ejection cylinder 1 and a guide rail pin 62 disposed on the ejection piston 2, the guide rail pin 62 being slidably connected to the guide rail 61.

[0031] The aforementioned guide rail 61 is provided with a blocking screw 63 for axially limiting the guide rail pin 62.

[0032] The aforementioned locking mechanism 5 includes a locking cylinder 51 fixed to the side wall of the ejection cylinder 1. A locking piston 52 is slidably connected inside the locking cylinder 51. The locking piston 52 is connected to a locking pin 53. The locking pin 53 passes through the side wall of the ejection cylinder 1 and the side wall of the ejection piston 2 in sequence and then gets stuck into the suspended object 4. A locking spring 54 is provided between the side of the locking piston 52 away from the locking pin 53 and the locking cylinder 51. An unlocking air inlet 55 is provided on the side wall of the locking cylinder 51 between the locking piston 52 and the ejection cylinder 1.

[0033] An angular velocity providing mechanism 7 is provided on the side of the extended end of the aforementioned ejection cylinder 1. The angular velocity providing mechanism 7 includes an angular velocity cylinder 71, an angular velocity piston 72 slidably connected inside the angular velocity cylinder 71, and the angular velocity piston 72 connected to a strike rod 73. The strike rod 73 can extend out of the angular velocity cylinder 71, and an angular velocity spring 74 is sleeved on the strike rod 73. An angular velocity air inlet 75 is provided on the angular velocity cylinder 71. When the suspended object 4 is ejected from the ejection cylinder 1, the angular velocity cylinder 71 is activated in a set sequence. The angular velocity piston 72 moves downward, pushing the strike rod 73 to act on the front of the suspended object, so that the suspended object 4 obtains a downward angular velocity. By adjusting the activation time and action time of the angular velocity cylinder 71, the magnitude of the angular velocity of the suspended object can be adjusted to achieve different angular velocity control.

[0034] Multiple cylinders are used as the ejection power, unlocking power, and angular acceleration power for the suspended object, respectively. Through timing control, a complete process of unlocking, ejection, and the rearward launch of the suspended object with additional angular velocity is formed.

[0035] Due to space constraints, the aircraft's belly compartment and ejection cylinder are integrated into one unit, with the ejection cylinder serving as a container for loading suspended objects before ejection.

[0036] The contact area between the ejection piston and the suspended object is designed with a surface that matches the shape of the suspended object, nesting the suspended object within the piston. Before ejection, the suspended object is fixed to the piston, which can only move backward along the cylinder axis. Due to the restriction of the mating surface, the suspended object can only move backward away from the piston. A pin is designed to penetrate the cylinder wall and piston wall, inserting into a small hole in the suspended object's ejection body, thus locking both the piston and the suspended object. Unlocking can be achieved simply by designing an unlocking cylinder to remove the pin.

[0037] Adjusting the pressure of the ejection cylinder allows for launching suspended objects at different speeds. Adjusting the action time and pressure of the angular velocity cylinder allows for applying different angular velocities to the suspended object.

[0038] The aforementioned method of using the wind tunnel test apparatus for simulating the rearward ejection of suspended objects from an aircraft includes the following steps:

[0039] S1. After installing the wind tunnel testing equipment on the belly of the aircraft, place it in the wind tunnel;

[0040] S2. During the wind tunnel test, once the flow field meets the requirements, the locking mechanism 5 is unlocked, high-pressure gas is introduced into the ejection gas inlet 3, which pushes the ejection piston 2 to eject the suspended object 4 backward into the wind tunnel flow field. The influence of each ejection parameter on the separation safety is investigated, and separation aerodynamic data is obtained.

[0041] In step 2, the unlocking process is as follows: the unlocking air inlet 55 is vented, which pushes the locking piston 52 to drive the locking pin 53 to retract into the locking cylinder 51 to complete the unlocking.

[0042] In step 2, when it is necessary to provide an angle to the suspended object 4, when the head end of the suspended object 4 is ejected from the ejection cylinder 1, the high-pressure gas from the angle velocity gas supply inlet 75 pushes the impact rod 73 to strike the head end of the suspended object 4 through the angular velocity piston 72, so that the suspended object 4 obtains a downward angular velocity.

[0043] The above description is merely a specific embodiment of the present invention, providing a detailed description of the invention. Parts not covered herein are conventional techniques. However, the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A wind tunnel testing device for simulating the rearward ejection of a suspended object from an aircraft, characterized in that, It includes an ejection cylinder, an ejection piston that is slidably connected along the axial direction inside the ejection cylinder, an ejection air inlet at the head end of the ejection cylinder, and the ejection piston is connected to the suspended object and locked together with the ejection piston by a locking mechanism. The locking mechanism includes a locking cylinder fixed to the side wall of the ejection cylinder, a locking piston slidably connected inside the locking cylinder, the locking piston being connected to a locking pin, the locking pin passing through the side wall of the ejection cylinder and the side wall of the ejection piston in sequence and then locking into the suspended object; a locking spring is provided between the side of the locking piston away from the locking pin and the locking cylinder, and an unlocking air inlet is provided on the side wall of the locking cylinder between the locking piston and the ejection cylinder. An angular velocity providing mechanism is provided on the side of the tail end of the ejection cylinder. The angular velocity providing mechanism includes an angular velocity cylinder, an angular velocity piston is slidably connected inside the angular velocity cylinder, the angular velocity piston is connected to the impact rod, the impact rod can extend out of the angular velocity cylinder, an angular velocity spring is sleeved on the impact rod, and an angular velocity air inlet is provided on the angular velocity cylinder.

2. The wind tunnel test apparatus for simulating the rearward ejection of a suspended object from an aircraft according to claim 1, characterized in that, The ejection cylinder and the ejection piston are slidably connected via a guide mechanism; the guide mechanism includes a guide rail disposed on the inner wall of the ejection cylinder and a guide rail pin disposed on the ejection piston, and the guide rail pin is slidably connected to the guide rail.

3. The wind tunnel test apparatus for simulating the rearward ejection of a suspended object from an aircraft according to claim 2, characterized in that, The guide rail is provided with a blocking screw for axially limiting the guide rail pin.

4. A method of using a wind tunnel testing apparatus for simulating the rearward ejection of a suspended object from an aircraft as described in any one of claims 1-3, characterized in that, The process includes the following steps: S1. After installing the wind tunnel test device on the belly of the aircraft, place it in the wind tunnel; S2. During the wind tunnel test, when the flow field meets the requirements, the locking mechanism is unlocked, high-pressure gas is introduced into the ejection gas inlet, and the ejection piston is pushed backward to eject the suspended object into the wind tunnel flow field. The impact of each ejection parameter on the separation safety is examined, and separation aerodynamic data is obtained.

5. The method of using the wind tunnel test apparatus for simulating the rearward ejection of a suspended object from an aircraft as described in claim 4, characterized in that, In step 2, the unlocking process is as follows: air is introduced into the unlocking air inlet, pushing the locking piston to retract the locking pin into the locking cylinder to complete the unlocking.

6. The method of using the wind tunnel test apparatus for simulating the rearward ejection of a suspended object from an aircraft as described in claim 4, characterized in that, In step 2, when it is necessary to provide an angle to the suspended object, when the head end of the suspended object is ejected from the ejection cylinder, the high-pressure gas from the angle velocity gas supply inlet pushes the impact rod through the angular velocity piston to strike the head end of the suspended object, so that the suspended object obtains angular velocity.

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