JP2008110678A - Deceleration method using fluid resistance of flying object, and high-speed moving body having the function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deceleration method which is applicable to a flying object having a conical nose cone on its fore end and flying at high speed, or a moving object navigating in water, and utilizing the fluid resistance operable by a compact and lightweight driving mechanism. <P>SOLUTION: In the deceleration method of a high-speed moving body, the fluid resistance is increased by moving a shroud (a cylindrical member) at the position of surrounding a cylindrical structure having a conical streamline shape on its fore end and moving in a fluid at high speed to the position of surrounding a streamline shape in the substantially cylindrical structure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flying object such as an aircraft or a rocket, a vehicle that moves at high speed on the ground, and a moving object that navigates underwater at high speed.

  As means for rapidly decelerating a flying object flying at high speed, there are a method using a fuel such as reverse injection and a method using an increase in fluid resistance such as a parachute or a spoiler employed in an airplane. Among them, the method using fuel such as reverse injection has to carry extra fuel for deceleration, which is a great disadvantage in the aviation field where weight greatly affects the performance of the flying object. Further, in the method using a parachute, a parachute injection mechanism, a wire for connecting the parachute and the flying object, and the like are required, which also causes an increase in weight. Also, the parachute has a weak point that it is structurally weak, and it is difficult to use the parachute especially when the speed of the flying object is supersonic. On the other hand, in a device called a spoiler, which is equipped on the main wing of a passenger aircraft and raises the air resistance by setting a part of the wing at an angle close to 90 ° with respect to the airflow, all the increased resistance is supported by the drive mechanism. Therefore, there is a problem that the drive mechanism is enlarged and the weight is increased.

  Non-Patent Document 1 is a document that introduces a reduction means using fluid resistance using a flexible structure, which has been devised for NASA speed reduction at NASA. Non-Patent Document 2 describes a spoiler that is currently used for deceleration when landing on a passenger aircraft or the like. Patent Documents 1 and 2 are domestic patents on brakes that use air resistance. Patent Document 1 relates to a guided vehicle that is launched from an aircraft, and is separated from the flying aircraft and flies toward the rear of the aircraft. Reduces the air resistance while the aircraft is mounted on the aircraft, shortens the time it takes for the flight speed to be received from the rear of the aircraft, and also ensures stable flight while the flight speed changes from the rear of the aircraft to the front. It is a problem to realize. In this flying body, when the aircraft is mounted, the nozzle of the propulsion device is covered to reduce the air resistance, and after separation from the aircraft, the rear dome that plays the role of an air brake, and the stability provided behind this fuselage A windmill attached to the tip of the wing and rotating by the air current, and detecting that the flight speed was received from the rear by this windmill, suddenly decelerates and generates lift perpendicular to the axle in front of the center of gravity of the flying object An air brake plate that expands in such a manner is provided.

Patent Document 2 is an idea to reduce the moving force of an aerodynamic brake for a vehicle, but an object is to provide a vehicle aerodynamic brake for decelerating a vehicle traveling at high speed. A rotating shaft provided across the center in the front-rear direction of a streamlined aerodynamic plate 3 with a cross-sectional shape of the front and rear being symmetrical, a column projecting from both sides of the vehicle and supporting both ends of the rotating shaft, and rotating the aerodynamic plate It consists of a drive device that rotates around the axis, and a control device that can arbitrarily set the angle of attack of the aerodynamic plate with respect to the running wind. Operation becomes possible, and the increase in vehicles can be reduced. Also, for sudden load increases, the angle of attack of the aerodynamic plate is reduced by the control device, so that excessive braking is not applied to the aerodynamic plate and the vehicle body. Can be prevented in advance.
These mechanisms require a large driving force and a large load during operation due to fluid pressure applied as a reaction when the air brake plate or aerodynamic brake is activated. For this reason, there is a problem that the weight of the airframe becomes large because it must be a large drive mechanism and support mechanism.
JP 2000-199700 A “Guided flying object” released on July 18, 2000 Japanese Laid-Open Patent Publication No. 8-72716 "Aerodynamic Brake for Vehicle" Published on March 19, 1996 Richardson, EH, Munk, MM, James, B. F: Review of NASA In-Space Propulsion Technology Progra Inflatable Decelerator Investments, AIAA-2005-1603, 18th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar, Munich, Germany, May 23- 26, 2005 Mccormick, B. W: Aerodynamics Aeronautics and Flight Mechanics, Second Edition, John Wiley and Son 1995, pp.522-524.

  The problem of the present invention is that it can be applied to a flying object having a cone-shaped nose cone at the tip or a high-speed flying object, or a moving object that navigates underwater. The object is to propose a deceleration method using operable fluid resistance.

The method of decelerating a high-speed moving body according to the present invention is a generally cylindrical structure that moves at high speed in a fluid having a conical streamlined shape at the tip, and is usually a shroud (cylindrical cylinder) located at a position surrounding the structure. The fluid member is moved to a position surrounding the streamlined shape during operation to increase the fluid resistance.
The high-speed moving body of the present invention is a generally cylindrical structure that moves at high speed in a fluid having a conical streamlined shape at the tip, a shroud having an inner diameter surrounding the outer peripheral surface of the structure, and the shroud And a drive mechanism that slides between the position surrounding the outer peripheral surface of the structure and the position surrounding the streamlined shape, and the fluid resistance is increased by sliding the shroud to the position surrounding the streamlined shape by the drive mechanism. A function of increasing the resistance and decelerating the resistance is provided.
The weightless experiment method of the present invention includes a step of transporting a structure, which is a weightless experiment machine, to the sky using a high-rise balloon, a step of separating the structure from the high-rise balloon in the sky, and a weightless experiment during natural fall. The step of performing, the step of moving the shroud when the low airspace is reached and executing the deceleration method according to claim 1 and the step of opening and collecting the parachute when fully decelerated are taken.

In the method for decelerating a high-speed moving body of the present invention, a fluid shroud is raised by moving a shroud that normally surrounds the structure to a position surrounding the streamlined shape during operation. Since the surface of the shroud is parallel to the flow direction, if the thickness is reduced as much as possible, the resistance of the fluid pressure is hardly received, and a large force is not required for driving. In addition, the device of the present invention that implements the deceleration method has no stress concentration because the force applied to the shroud main body is only the force in the outward direction of the cylinder (when the viscosity of the fluid is ignored) as a reaction to increase the fluid resistance. The shroud itself can be absorbed with a tensile strength that provides the most resistance to the structure. Accordingly, the power required for the movable mechanism is extremely small, and it is not necessary to increase the thickness of the shroud. As a result, the high-speed moving body can be decelerated with a simple and lightweight mechanism. Further, since the fluid drag acting on the moving body during navigation can be arbitrarily adjusted, it can be used when changing the flight route such as a sudden turn. This mechanism is effective not only when the flow is subsonic, but also when the flow is supersonic. It can be applied not only to an axially symmetric object such as a cone but also to a two-dimensional shape such as an airfoil. However, in the case of an axially symmetric object, the shroud can be formed into a cylindrical shape that is resistant to external forces. This is also advantageous in terms of strength.
Furthermore, when the deceleration method of the present invention is applied to a weightless experiment method, effective deceleration can be realized in a low air region where atmospheric pressure is applied, and the experimental machine can be safely and reliably recovered by a simple means called a parachute.

  FIG. 1 shows a basic structure for realizing a method for decelerating a cylindrical structure according to the present invention. Reference numeral 1 denotes a high-speed moving body in which a nose cone 1b is formed at the tip of the cylindrical body 1a. Reference numeral 2 denotes a shroud, which is disposed so as to partially surround the high-speed moving body 1. During normal navigation, as shown in the upper part of FIG. 1, the shroud 2 is installed at a position covering the outer peripheral surface of the cylindrical body 1a of the high-speed moving body 1. In this embodiment, the flow generated from the tip of the nose cone 1b is generated. Since the shroud 2 is located at a position where it is not obstructed, the presence of the shroud 2 has little influence on the fluid. At the time of deceleration, as shown in the lower part of FIG. 1, the shroud 2 is slid toward the tip of the nose cone 1b against the flow, and the shroud 2 is positioned around the nose cone 1b. The force received from the fluid during this movement is that the shroud 2 has a cylindrical shape, so that the area in contact with the flow becomes an end face corresponding to the thickness, and resistance can be extremely small. This means that the mechanism for driving the shroud 2 does not have to be large, and this point is one of the great technical significance of the present invention that leads to weight reduction from the viewpoint of the prior art. When this form is adopted, the flow generated from the tip of the nose cone 1b hits the inner peripheral surface of the shroud 2 and cannot flow along the cylindrical body 1a, but the outer surface of the nose cone 1b and the shroud 2 surrounding it. Convection is caused by the reverse flow between the inner peripheral surfaces of each other. This phenomenon causes the fluid resistance of the nose cone 1b to rise rapidly and generate a backward force. At that time, the important point is that the reaction is applied to the inner peripheral surface of the shroud 2, and it is possible to withstand the force of spreading the outside with the highest tensile strength in the cylindrical body. This means that it is not necessary to make the shroud into a solid structure without darkness, which means that a thin structure is sufficient. This is another major technical significance of the present invention that leads to weight reduction from the viewpoint of the prior art.

The result of the verification test in the supersonic wind tunnel conducted in the present invention will be described. In the 0.6 × 0.6m supersonic wind tunnel of the Japan Aerospace Exploration Agency's space science research headquarters, a demonstration test of the proposed mechanism was conducted using a wind tunnel model with a conical diameter of 40mm and a cylindrical shroud of 46mm. As a result, it was confirmed that the mechanism works effectively in the Mach number range of 1.5 to 4.0.
Fig. 2 shows the wind tunnel model used in this demonstration test. A cylindrical shroud having a thickness of 3 mm is arranged outside the flying object model having a conical nose cone having a half apex angle of 16 °. At this time, since the diameter of the flying object model is 40 mm, the length of the nose cone portion is about 70 mm. In the figure, the left side shows the form during normal navigation, and the right side shows the form when the mechanism is operated. In this figure, the shroud 2 is moved forward by 40 mm. In this model, in order to keep the fluid resistance of the shroud low, the shape of the front end face of the shroud was tapered outward. As a result, when the vehicle is in the retracted position during normal navigation, it becomes an extension of the cone shape of the nose cone and does not disturb the flow. The above model was installed in the supersonic wind tunnel described above, and a wind tunnel experiment was conducted. FIG. 3 shows a schlieren photograph of changes in the flow field when the mechanism is not operated on the left side and when it is operated on the right side (40 mm extension as in FIG. 2). This photo is taken when the mainstream Mach number is 1.5. As can be seen from the photo on the left, when the shroud mechanism is not operated, a shock wave that is the same as that of a flying object with a normal nose cone can be observed. On the other hand, from the photograph when the mechanism according to the present invention on the right side is operated, it can be seen that a strong arcuate shock wave is generated in front of the cone. A large fluid resistance is applied to the tip of the flying object by causing such a drastic change in the airflow. FIG. 4 shows the relationship between the shroud position and the drag coefficient (Cd) when the mainstream Mach number is 1.5, 2.5, and 4.0. The shroud position 0 mm indicates when the vehicle is in the retracted position during normal operation, and the data was taken by advancing the shroud position to 10 mm, 25 mm, 40 mm, 55 mm, and 70 mm. It can be seen that for a nose cone having a length of about 70 mm, the drag coefficient increases greatly as the shroud covering progresses to 10 mm, 25 mm, and 40 mm, but beyond that, there is no significant increase. Overall, by extending the shroud forward, the drag force applied to the model is about 3.5 times when the Mach number is 1.5 and about 8 times when the Mach number is 4.0, and the higher the Mach number, the stronger the fluid resistance. I understand that I will receive it.

  FIG. 5 shows an example in which a rocket vehicle equipped with a shroud according to this patent is used in a weightless experiment dropped from a high-rise balloon. The weightless experimental machine 3 equipped with the cylindrical shroud 2 proposed in the present invention is lifted up to the vicinity of 40 km above the high-rise balloon 4 filled with helium as shown in FIG. Disconnect from. The zero-gravity experimental machine 3 performs the experiment while dropping weightlessly. At this time, it is desirable that the air resistance of the airframe is as small as possible so that the zero-gravity experimental time can be taken. Accordingly, at this time, the test is performed with the cylindrical shroud pulled behind the nose cone as shown in FIG. In a drop experiment from an altitude of 40 km, the experimental aircraft reaches supersonic speed due to acceleration by gravity, and a shock wave is formed in the nose cone. When the altitude decreases due to falling, the zero gravity condition required by air resistance cannot be obtained. Thereafter, the airframe decelerates for recovery. At this time, the cylindrical shroud 2 is pushed forward by a mechanism such as an actuator such as a spring mechanism or an air cylinder to create a strong arcuate shock wave in front of the airframe to increase the air resistance. The form at this time is shown in FIG. After the aircraft has sufficiently slowed down, open the parachute and collect the aircraft.

  It can be applied to all flying objects that fly in the air at high speed, such as aircraft, rockets, and zero-gravity experimental devices. The same mechanism can also be used for deceleration of vehicles such as the Shinkansen that travel at high speed on the ground and moving bodies that travel underwater.

It is a figure explaining the principle of the deceleration method of this invention. It is a figure which shows the wind tunnel model for the verification test of this invention. This is a Schlieren photo showing the flow field in a wind tunnel experiment. It is a graph which shows the relationship data of a shroud position and the drag coefficient Cd. It is a figure explaining the Example which applied this invention to the weightless experiment machine.

Explanation of symbols

1 High-speed moving body 1a Cylindrical body
1b Nose cone 2 Shroud 3 Zero-gravity experimental equipment 4 High-rise balloon

Claims (4)

  In a generally cylindrical structure that moves at high speed in a fluid having a conical streamlined shape at the tip, a shroud that normally surrounds the structure is moved to a position that surrounds the streamlined shape during operation. A method of decelerating a high-speed moving body that increases fluid resistance.   In a generally cylindrical structure that moves at high speed in a fluid having a conical streamlined shape at the tip, a shroud having an inner diameter surrounding the outer peripheral surface of the structure, and a position surrounding the shroud around the outer peripheral surface of the structure; Provided with a drive mechanism for sliding between positions surrounding the streamlined shape, and having a function of increasing the fluid resistance and decelerating by sliding the shroud to a position surrounding the streamlined shape with the drive mechanism. Fast moving body.   The generally cylindrical structure that moves at high speed in a fluid is either a flying object such as an aircraft or a rocket flying at high speed, a vehicle that moves at high speed on the ground, or a moving object that navigates underwater. Fast moving body.   A step of transporting the structure, which is a weightless experiment machine, to the sky using a high-rise balloon, a step of separating the structure from the high-rise balloon in the sky, a step of performing a weightless experiment during natural fall, and a low-air area A zero-gravity experimental technique in which the shroud is moved to implement the deceleration method according to claim 1 and the step of opening and collecting the parachute when fully decelerated.