Computing method of model parameters in icing wind tunnel experiment under supercooled large droplet condition

A technology of wind tunnel test and model parameters, which is applied in the field of aerospace, can solve the problems of poor freezing experiments of supercooled large water droplets and failure to reflect real icing, etc.

Inactive Publication Date: 2015-01-07
AERODYNAMICS NAT KEY LAB
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The object of the invention of the present invention is: the effect of the existing supercooled small water droplet icing test parameter selection method for the supercooled large water droplet icing test is not good, and the icing on the s

Method used

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  • Computing method of model parameters in icing wind tunnel experiment under supercooled large droplet condition
  • Computing method of model parameters in icing wind tunnel experiment under supercooled large droplet condition
  • Computing method of model parameters in icing wind tunnel experiment under supercooled large droplet condition

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0115] The NACA0012 airfoil with a chord length of 0.5m is selected as the reference full-scale shape, and the test model size is taken as 0.3m.

[0116] The actual flight conditions are: chord length: L f =0.5m; flight speed: V f =95.0m / s; pressure: P f =91032Pa; water droplet diameter: d f =60μm; liquid water content: LWC f =0.22g / m 3 ; Freezing time: t f =6min; freezing temperature: T f =253K.

[0117] Adopt the technical scheme of the present invention, carry out calculation, the test parameter that can calculate model is: chord length: L m =0.3m; flight speed: V m =119.1m / s; droplet diameter: d m =38μm; liquid water content: LWC m =0.163g / m 3 ; Freezing time: t f =232.9s; freezing temperature: T f =255.2K.

[0118] For the real flight condition of embodiment 1 and its corresponding test condition, figure 1 , 2 The comparison charts of the normalized results are given respectively. figure 1 is the comparison chart of normalized water droplet collection coe...

Embodiment 2

[0120] The NACA0012 airfoil with a chord length of 0.5m is selected as the reference full-scale shape, and the test model size is taken as 0.3m.

[0121] The actual flight conditions are:; chord length: L f =0.5m; flight speed: V f =90.0m / s; pressure: P f =89032Pa; water drop diameter: d f =80μm; liquid water content: LWC f =0.15g / m 3 ; Freezing time: t f =6min; freezing temperature: T f = 248K.

[0122] Corresponding to the real flight conditions, the calculated experimental parameters of the model are: chord length: L m =0.3m; flight speed: V m =113.6m / s; water droplet diameter: d m =50.2μm; liquid water content: LWC m =0.109g / m 3 ; Freezing time: t f =234.2s; freezing temperature: T f =251.2K.

[0123] For the real flight condition of embodiment 2 and its corresponding test condition, image 3 , 4 The comparison charts of the normalized results are given respectively. image 3 is the comparison chart of normalized water droplet collection coefficient, Fig...

Embodiment 3

[0125] The NACA0012 airfoil with a chord length of 0.5m is selected as the reference full-scale shape, and the test model size is taken as 0.3m.

[0126] Real flight conditions: Chord length: L f =0.5m; flight speed: V f =89.0m / s; Pressure: P f =89032Pa; water drop diameter: d f =100μm; liquid water content: LWC f =0.5g / m 3 ; Freezing time: t f =6min; freezing temperature: T f =252K.

[0127] The calculated experimental parameters of the model are: chord length: L m =0.3m; flight speed: V m =123.4m / s; droplet diameter: d m =58μm; liquid water content: LWC m =0.286g / m 3 ; Freezing time: t f =271s; freezing temperature: T f =253K.

[0128] For the real flight condition of embodiment 3 and its corresponding test condition, Figure 5 , 6 The comparison charts of the normalized results are given respectively. Figure 5 is the comparison chart of normalized water droplet collection coefficient, Image 6 It is the comparison chart of the normalized icing shape. Fi...

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Abstract

The invention discloses a computing method of model parameters in an icing wind tunnel experiment under a supercooled large droplet condition and aims at solving the problems that an existing parameter selecting method for a supercooled small droplet icing experiment does not function well if being applied to a supercooled large droplet icing experiment and that the real icing condition cannot be reflected by icing on a scale model of the airplane. The computing method of the model parameters in the icing wind tunnel experiment under the supercooled large droplet condition is capable of orderly giving the experimental parameters of a wind tunnel test section such as air velocity, average droplet grain diameter, air pressure, liquid water content, icing time and low supercooled water temperature corresponding to real icing flying conditions by use of a theoretical derivation and numerical computation method after determining the scale relation of the model and the real airplane. An aircraft icing wind tunnel experiment is performed according to the converted test parameters, and the experimental result and the real result are capable of meeting the similarity requirement on the major characteristics of the icing process. As a result, the computing method of the model parameters in the icing wind tunnel experiment under the supercooled large droplet condition is capable of obtaining the model parameters for the icing wind tunnel experiment; the corresponding parameters are capable of reflecting the real icing condition in the icing wind tunnel experiment.

Description

technical field [0001] The invention relates to the field of aerospace, in particular to a method for calculating model parameters in an icing wind tunnel test under the condition of supercooled large water droplets. Background technique [0002] When the aircraft is flying at a temperature below freezing point, if it encounters a cloud layer containing supercooled water droplets (supercooled water droplets refer to water droplets whose temperature is lower than freezing point but still maintains a liquid state), the water droplets in the cloud layer will hit the surface of the aircraft. Icing occurs in and near the impact area. Aircraft icing is a phenomenon that widely exists in flight practice, and it is also one of the main hidden dangers that cause flight safety accidents. Supercooled Large Droplets (English full name Supercooled Large Droplets, usually abbreviated as SLD) generally refers to liquid supercooled water droplets with a diameter greater than 50 μm. [000...

Claims

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Application Information

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IPC IPC(8): G06F19/00
Inventor 周志宏易贤桂业伟朱国林王勋年
Owner AERODYNAMICS NAT KEY LAB
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