Method for calibrating and measuring supersonic flow field density field

A technology of supersonic flow and calibration method, which is applied in calibrating the density-NPLS image gray curve of supersonic flow field and measuring the medium density of supersonic flow field, which can solve the problems of measurement error, spatial resolution and low signal-to-noise ratio in low-density areas , to achieve the effect of improving measurement accuracy, temporal and spatial resolution and signal-to-noise ratio, and broadening the measurement range

Active Publication Date: 2012-10-03
NAT UNIV OF DEFENSE TECH
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Problems solved by technology

[0008] The purpose of the present invention is to provide a method for calibrating density-NPLS image grayscale curves in supersonic flow field, to solve the problem of low spatial resolution and signal-to-noise ratio of conventional measurement methods, and problems existing in the measurement of low-density regions by existing NPLS-DT. Large error technical problem

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  • Method for calibrating and measuring supersonic flow field density field
  • Method for calibrating and measuring supersonic flow field density field
  • Method for calibrating and measuring supersonic flow field density field

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[0028] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways defined and covered by the claims.

[0029] see figure 1 , the NPLS system of the present invention is used to correct the density-image grayscale curve of the supersonic flow field in the supersonic wind tunnel 8 and measure the distribution of the plane density of the three-dimensional transient supersonic flow field. The system includes light source system, recording system, synchronous control system, tracer system and analysis system.

[0030] The light source system is a laser 1, and the laser 1 preferably uses a double-cavity Nd:Yag pulsed laser. Each laser cavity of the dual-cavity laser 1 can emit two beams of laser light with a pulse width of 6 ns in a very short time interval, and form a thin sheet of light 9 after passing through the optical arm 2 and the sheet light lens ...

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Abstract

The invention provides a method for calibrating a supersonic flow field density field. According to the method, a supersonic flow field density-nanoparticle-based planar laser scattering (NPLS) image gray curve is calibrated by adopting a comprehensive oblique shock wave and expansion wave calibration method based on an NPLS technology. The method comprises the following steps of: 1, uniformly scattering trace particles in supersonic incoming flow, and shooting a particle image according to the instruction of a computer by a charge coupled device (CCD); 2, continuously adjusting obliqueness of an attack angle alpha in a supersonic wind tunnel, and acquiring a group of (rhoi, Ii) (i=1, 2, L, n-1) data by changing the oblique attack angle alpha; 3, placing expansion wave generators in the supersonic wind tunnel, and acquiring the other group of (rhoi, Ii) (i=n, n+1, L, N) data by placing the expansion wave generators with different deflection angles; and 4, performing polynomial fitting on the two groups of data to obtain the supersonic flow field density-NPLS image gray relation curve, namely rho=alapha0+alpha1I+alpha2I2+alpha3I3+K. The method aims to solve the technical problems of low spatial resolution and low signal-noise ratio and high error on measurement of a low-density area.

Description

technical field [0001] The invention relates to a method for calibrating a supersonic density field, in particular to a method for calibrating supersonic flow field density-NPLS image grayscale curves based on NPLS technology and using oblique shock waves and expansion waves. In addition, the present invention also relates to a method for measuring density in a supersonic flow field comprising using the calibration method described above. Background technique [0002] The measurement of supersonic density field is an important part of experimental aerodynamics. The current measurement methods mainly include Filtered Rayleigh Scattering (FRS), Planar Laser Induced Fluorescence (PLIF), Background Guided Schlieren ( Background Oriented Schlieren, BOS) and Nanoparticle-based Planar Laser Scattering (NPLS) supersonic density field measurement method NPLS-DT (NPLS-based Density Technique), etc. [0003] FRS is a laser-based molecular scattering technique, using gas molecules in t...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01M9/00
Inventor 易仕和田立丰赵玉新何霖陈植
Owner NAT UNIV OF DEFENSE TECH
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