A method for estimating the off-site load of raindrops during parachute drop
A raindrop and load technology, applied in the field of aviation life-saving, can solve the problems of failure of recovery or airborne, great influence of parachute aerodynamic deceleration performance, difficulty in obtaining load, etc., to avoid chance and randomness, and reduce experimental costs.
Active Publication Date: 2019-10-29
CIVIL AVIATION FLIGHT UNIV OF CHINA
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Problems solved by technology
[0003] Raindrop off-site load, as an important external environmental load, has a great impact on the aerodynamic deceleration performance of the parachute, and can even cause recovery or airborne failure
However, due to the randomness and contingency of precipitation, as well as the existing data acquisition technology, it is difficult to obtain the load by airdrop method
Method used
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[0025] Below in conjunction with accompanying drawing and specific embodiment the technical solution of the present invention is described in further detail:
[0026] The present invention is in order to solve the difficult problem that obtains the parachute drop process raindrop off-site load, below with the method disclosed by the present invention with July 12, 2010 Nanjing area precipitation (Pu Jiangping, Zhang Hao, Zhou Xiao etc. Convective precipitation raindrop spectrum feature and its Comparative analysis with radar reflectivity factor. Meteorological Science, 2012, 32(3):253-259.) as an example, to estimate the off-site load of raindrops during parachute drop of C9 parachute.
[0027] Step 1: According to the measured precipitation raindrop spectrum, determine the dominant diameter D of the precipitation raindrop p and its steady descent velocity v y .
[0028] According to the literature (Pu Jiangping, Zhang Hao, Zhou Xiao, etc. Convective precipitation raindrop s...
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The invention discloses a raindrop field external load estimation method in a parachute landing process. The method comprises a step of determining a micro characteristic amount of main raindrops according to an actually measured precipitation raindrop spectra, a step of determining different working conditions according to an aerodynamic shape, fabric tension of different parts and oblique angles in a parachute steady drop process, using the high speed camera technology to capture a whole process that droplets strike a canopy under different working conditions, and obtaining a needed time that the droplets are deformed to maximum flat states for a first time and speeds in a vertical direction through post image data processing, a step of estimating raindrop impact under the working conditions according to the theorem of momentum, and a step of calculating an external load of a raindrop field to the canopy according to a raindrop surface density in the raindrop spectra and the impact in the above different working conditions. According to the method, a basis can be provided for parachute optimization design and parachute opening failure prevention in a rainstorm environment.
Description
technical field [0001] The invention relates to a method for estimating the off-site load of raindrops during a parachuting process, and belongs to the technical field of aviation lifesaving. Background technique [0002] As an important deceleration life-saving equipment, parachute is widely used in the fields of aviation, aerospace and weapons. The current parachute design or research is mainly based on ideal weather conditions, but in some special cases, such as airdrops for disaster relief in rainy weather or lifesaving parachutes for complete aircraft, it is inevitable that raindrops will hit the parachute. [0003] Raindrop off-site load, as an important external environmental load, has a great impact on the aerodynamic deceleration performance of the parachute, and can even cause recovery or airborne failure. However, due to the randomness and contingency of precipitation, as well as the existing data acquisition technology, it is difficult to obtain the load by aird...
Claims
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IPC IPC(8): G01L11/02
CPCG01L11/02
Inventor 程涵邱超龙江马尧贺强陈晨孙鹏郭琪磊孙雪宾杨芮
Owner CIVIL AVIATION FLIGHT UNIV OF CHINA