CN111332438A - Active load reduction structure of aircraft - Google Patents

Abstract

The invention relates to an active load reduction structure for an aircraft. Including the head of the aircraft, the middle section of the aircraft, the tail section of the aircraft, the jet rectifier valve, the jet on-off valve and the high-pressure gas cylinder part. Among them, the jet rectifying valve is located in the central area of the aircraft head, which is a device for jetting uniform high-pressure gas. The jet on-off valve is located at the rear of the jet rectifier valve, which is connected with the jet rectifier valve and the high-pressure gas cylinder, and controls the on-off of the air flow, which is directly controlled by the aircraft jet control system. The high-pressure gas cylinder is located behind the jet on-off valve and stores all the high-pressure gas needed to generate the supercavitation. The present invention applies the supercavitation technology to the problem of load reduction in the high-speed water entry process of the aircraft, and has more excellent load reduction performance compared with the traditional buffer head cap and the load reduction head type load reduction technology. The present invention uses high-pressure compressed air as the gas source, and compared with the gas jet to reduce the load, the system is more compact and compact, and is more suitable for application to small and medium-sized underwater vehicles.

Description

A structure for active load reduction of aircraft

technical field

The invention relates to the field of aircraft high-speed water entry and load reduction, in particular to an aircraft active load reduction structure.

Background technique

The underwater vehicle will inevitably undergo the process of entering the water after being launched by a rocket or an aircraft. The water entry process is a transient process with fast speed and short time, during which a huge impact load will be generated on the vehicle. If the load is not lowered by some technical means, it will cause obvious or potential damage to the shape, structure, devices, etc. of the aircraft.

Supercavitation technology is a very effective method of derating. Russia first proposed the concept of an underwater supercavitating vehicle. By enclosing the vehicle in a cavitation, the vehicle is isolated from the water, thereby greatly reducing the resistance of the underwater navigation of the vehicle. The basic principle of supercavitation drag reduction is achieved by reducing the density of the fluid medium around the vehicle. Through artificial ventilation, the area of the naturally cavitated cavitation can be increased, and gradually develop into a supercavitation surrounding the aircraft, and the cavitation can be stabilized. Based on the same principle, the supercavitation drag reduction can be applied to the load reduction of the aircraft during the water entry stage, and the impact load can be reduced by forming a wrapping cavitation through the jet of the aircraft head.

Vehicle high-speed water entry load reduction technology is one of the core technologies in the water entry field. Traditional load reduction technologies include the use of brittle buffer head caps, flexible buffer head caps, and the application of special head shapes with low impact force. However, the load reduction capability of the above technologies is limited, and with the further increase of the water entry speed, the above technologies face the risk of failure. The invention patent with the application publication number CN 109341443A discloses a method for high-speed water entry of missiles based on reverse jet. The invention is mainly composed of a gas generator, a Laval nozzle and a long tail pipe. Before entering the water, the gas generator starts to work, and a large amount of gas is generated into the Laval nozzle through the long tail pipe, and is accelerated to supersonic speed through the Laval nozzle, thereby wrapping the missile when it enters the water. This method takes advantage of the fact that the missile itself carries fuel and uses local materials to provide protection for the missile to enter the water at high speed; however, when applied to an underwater vehicle, a complete set of gas generation and injection systems needs to be placed inside the already very compact vehicle. The resulting weight, space, and performance costs are unacceptable.

SUMMARY OF THE INVENTION

technical problem to be solved

In order to avoid the deficiencies of the prior art, the present invention proposes an active load reduction structure for an aircraft, which uses compressed gas instead of fuel gas to work, generates supercavitation that wraps the projectile at the moment of entering the water, and applies the supercavitation technology to solve the problem of entering the water. The problem of load reduction has excellent load reduction performance and small engineering cost, and has great application potential.

Technical solutions

An active load reduction structure of an aircraft, the aircraft is the head of the aircraft, the middle section of the aircraft and the tail section of the aircraft; it is characterized in that an active load reduction structure is arranged on the head of the aircraft, including a jet rectifying valve, a jet on-off valve and a The high-pressure gas cylinder, the jet rectifier valve is installed in the center of the aircraft head, and the jet rectifier valve contains a plurality of evenly distributed flat-shaped jet holes, which can evenly jet air; the uniformity includes both the space between the jet holes The uniformity of the jet flow, including the uniformity of the jet flow of a single jet hole at different angles; the jet on-off valve is located behind the jet rectifier valve, which is connected to the jet rectifier valve and the high-pressure gas cylinder; the state of the jet on-off valve is controlled by the jet The control of the system, when the aircraft is about to touch the water, the jet on-off valve is opened, and the high-pressure gas in the high-pressure gas cylinder behind the jet on-off valve is ejected through the jet on-off valve and the jet rectifier valve, forming an air that wraps the aircraft. bubble, to achieve the purpose of supercavitation load reduction.

In order to ensure that the airflow can be ejected and form a supercavitation surrounding the aircraft, the gas jet velocity at the beginning of cavitation must satisfy:

where:

P _g ——the gas pressure in the cavity, that is, the cavitation pressure;

ρ _g ——gas density;

v _g ——gas velocity;

P _∝ ——the pressure of water at infinity;

v _{∞ ——the} speed of water at infinity;

ρ is the density of water.

beneficial effect

An aircraft active load reduction structure proposed by the invention includes the aircraft head, the middle section of the aircraft, the tail section of the aircraft, a jet rectifying valve, a jet on-off valve and a high-pressure gas cylinder part. Among them, the jet rectifier valve is located in the central area of the aircraft head, which is a device for jetting uniform high-pressure gas. The jet on-off valve is located at the rear of the jet rectifier valve, which is connected with the jet rectifier valve and the high-pressure gas cylinder, and controls the on-off of the air flow, which is directly controlled by the aircraft jet control system. The high-pressure gas cylinder is located behind the jet on-off valve and stores all the high-pressure gas needed to generate supercavitation. The present invention applies the supercavitation technology to the problem of load reduction in the high-speed water entry process of the aircraft, and has more excellent load reduction performance compared with the traditional buffer head cap and the load reduction head type load reduction technology. The present invention uses high-pressure compressed air as the gas source, and compared with the gas jet to reduce the load, the system is more compact and compact, and is more suitable for application to small and medium-sized underwater vehicles.

Description of drawings

Figure 1 is an overall schematic diagram of the design of an aircraft's active load reduction structure

Figure 2 is a partial view of the design of an aircraft's active load reduction structure

Description of reference numerals: 1- the head of the aircraft, 2- the middle section of the aircraft, 3- the tail section of the aircraft, 4- jet rectifying valve, 5- jet on-off valve, 6- high pressure gas cylinder.

Detailed ways

The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

As shown in FIG. 1 , the application object of the present invention is an underwater vehicle. Generally, the underwater vehicle can be divided into the head section 1 of the vehicle, the middle section 2 of the vehicle, and the tail section 3 of the vehicle. In the present invention, an active load reduction system is arranged in the head 1 of the aircraft, and the active load reduction system occupies less space and does not have a great impact on the overall layout. The active load reduction system includes a jet rectifying valve 4 , a jet on-off valve 5 and a high-pressure gas cylinder 6 . The jet rectifying valve 4 is installed in the center of the aircraft head 1 , and the jet rectifying valve 4 includes a plurality of evenly distributed flat-shaped jet holes, which can jet air evenly. The uniformity here includes not only the uniformity of the jet air flow between the various jet holes, but also the uniformity of the jet flow of a single jet hole at different angles. As shown in FIG. 2, the jet on-off valve 5 is located next to the jet rectifier valve, and is located behind the jet rectifier valve. The state of the jet on-off valve 5 is controlled by the jet control system. When the aircraft is about to touch the water, the jet on-off valve 5 is opened, and the high-pressure gas in the high-pressure gas cylinder 6 behind the jet on-off valve 5 passes through the jet on-off valve. 5 and the jet rectifying valve 4 are ejected to form a cavitation that wraps the aircraft, so as to achieve the purpose of supercavitation and load reduction.

In addition, in order to ensure that the air flow can be ejected and form a supercavity surrounding the aircraft, the pressure of the jet gas must be greater than the pressure of the liquid at the stagnation point of the head of the aircraft. According to the Bernoulli equation after the supercavitation is generated:

where:

P _g ——the gas pressure in the cavity, that is, the cavitation pressure;

ρ _g ——gas density;

v _g ——gas velocity;

P _{∞ ——the} pressure of water at infinity;

v _{∞ ——the} speed of water at infinity;

ρ is the density of water.

From this, it can be estimated that the gas jet velocity at the start of cavitation must satisfy:

Therefore, in practical engineering, the pressure of the injected gas should meet the requirements of formula ②.

Claims (2)

1. An active load-reduction structure for an aircraft, the aircraft is the head of the aircraft (1), the middle section of the aircraft (2) and the tail section of the aircraft (3); it is characterized in that the head (1) of the aircraft is provided with an active The load reducing structure includes a jet rectifying valve (4), a jet on-off valve (5) and a high-pressure gas cylinder (6). The jet rectifying valve (4) is installed in the center of the aircraft head (1), and the jet rectifying valve ( 4) It contains a plurality of uniformly distributed flat-shaped jet holes, which can evenly jet air; the uniformity includes both the uniformity of jet air between each jet hole and the jet flow of a single jet hole at different angles. Evenly; the jet on-off valve (5) is located behind the jet rectifier valve (4), and is connected to the jet rectifier valve (4) and the high-pressure gas cylinder (6); the state of the jet on-off valve (5) is controlled by the jet control system , when the aircraft is about to touch the water, the jet on-off valve (5) is opened, and the high-pressure gas in the high-pressure gas cylinder (6) behind the jet on-off valve (5) passes through the jet on-off valve (5) and the jet rectifier valve (4) It is ejected to form a cavitation that wraps the aircraft, so as to achieve the purpose of supercavitation and load reduction. 2. a kind of aircraft active load-relief structure according to claim 1 is characterized in that in order to ensure that the air flow can be ejected and form the supercavitation surrounding the aircraft, the gas jet velocity when starting the cavitation generation must satisfy:

where: P _g ——the gas pressure in the cavity, that is, the cavitation pressure; ρ _g ——gas density; v _g ——gas velocity; P _{∞ ——the} pressure of water at infinity; v _{∞ ——the} speed of water at infinity; ρ is the density of water.

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