Wind tunnel cold leakage monitoring method based on global normal distribution and local outlier factor

An outlier factor and normal distribution technology, applied in the wind tunnel field, can solve the problems of high false alarm rate and difficulty in effectively obtaining the leakage of cold liquid on the surface of the wind tunnel, so as to ensure the elimination and improve the detection accuracy

Active Publication Date: 2021-09-28
中国空气动力研究与发展中心设备设计与测试技术研究所
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0004] The invention provides a wind tunnel cooling leakage monitoring method based on global normal distribution and local outlier factors to solve the problem of high false alarm rate and difficulty in effectively obtaining wind tunnel temperature when distributed optical fibers are used to monitor the surface temperature of the wind tunnel in the prior art. The problem of surface cooling and liquid leakage, to achieve the purpose of reducing the false alarm rate and effectively detecting the surface of the wind tunnel for cooling and liquid leakage

Method used

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  • Wind tunnel cold leakage monitoring method based on global normal distribution and local outlier factor
  • Wind tunnel cold leakage monitoring method based on global normal distribution and local outlier factor
  • Wind tunnel cold leakage monitoring method based on global normal distribution and local outlier factor

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Embodiment 1

[0073] Such as figure 1 The wind tunnel cooling leakage monitoring method based on the global normal distribution and local outlier factors shown specifically includes:

[0074] Step 1. Obtain the temperature measurement point data of the temperature measurement optical fiber laid on the outer surface of the wind tunnel.

[0075] The temperature measurement optical fiber can accurately measure the temperature, and the temperature data obtained by the temperature measurement optical fiber is a single point. The points formed by optical fiber temperature measurement are ( X , Y , Z , T ),in X , Y , Z is the coordinate of the temperature measurement point in the wind tunnel coordinate system, T is the temperature.

[0076] Project the temperature measurement point to ( X , Y ) forms a grid point, which is formed by constructing the grid point and the temperature value of the optical fiber ( X , Y , T ) of the three-dimensional scattered point coordinates such as ...

Embodiment 2

[0097] In this embodiment, the X wind tunnel is taken as an example, and the method described in Embodiment 1 is used in the wind tunnel leakage monitoring system; the X wind tunnel is a continuous closed back flow transonic wind tunnel driven by an axial flow compressor. Compressor power 60MW. The wind tunnel is composed of the main circuit of the tunnel body, auxiliary systems and workshops. The temperature range of the operating medium in the wind tunnel is -196°C~50°C. The inner layer of the tunnel is a heat insulating layer, and the outer layer is a stainless steel shell. Blocks are spliced ​​together.

[0098] According to the design requirements of the insulation layer, under normal circumstances, the temperature on the surface of the insulation layer should not be lower than the local dew point temperature. Once the insulation layer fails, it will cause the surface temperature of the cavity to drop. During the operation of the wind tunnel, it is necessary to monitor...

Embodiment 3

[0141] On the basis of Embodiment 2, this embodiment optimizes the visual temperature measurement subsystem:

[0142] According to the requirements of the wind tunnel building in this embodiment, the imaging equipment in the visual temperature measurement subsystem is installed on the side wall of the wind tunnel building to achieve a reasonable layout and maximize the observation of the upper surface of the tunnel body.

[0143] The camera layout considers several factors: (1) the camera layout needs to cover the upper surface of the cave; Basis; (3) Since this embodiment is a recirculation wind tunnel, when the camera is arranged around the walls of the wind tunnel workshop, it is necessary to consider the outer surface of the nearby cave (close to the wall) and the inner and outer surfaces of the distant cave. Surface (not close to the wall), how to use the camera to monitor reasonably.

[0144] In this embodiment, the outer surface of the wind tunnel with a circumference ...

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Abstract

The invention discloses a wind tunnel cold leakage monitoring method based on global normal distribution and local outlier factors. The method comprises the steps of obtaining temperature measurement point data of a temperature measurement optical fiber laid on the outer surface of a wind tunnel; performing global anomaly detection on all the temperature measurement points based on normal distribution to obtain global anomaly points; carrying out local anomaly screening on all global abnormal points based on a local outlier factor, and taking the screened local abnormal points as stable cold leakage points; and establishing a cold leakage area by taking all the stable cold leakage points as supports. The invention provides a wind tunnel cold leakage monitoring method based on global normal distribution and local outlier factors to solve the problems that in the prior art, when distributed optical fibers are adopted to monitor the surface temperature of a wind tunnel, the false alarm rate is high and the cold leakage and liquid leakage conditions of the surface of the wind tunnel are difficult to effectively obtain.The purposes of reducing the false alarm rate and effectively detecting cold and liquid leakage on the surface of the wind tunnel are achieved.

Description

technical field [0001] The invention relates to the field of wind tunnels, in particular to a wind tunnel cooling leakage monitoring method based on global normal distribution and local outlier factors. Background technique [0002] Wind tunnel test, simply put, is based on the principle of relativity of motion, fixing the model or object of the aircraft in an artificial environment on the ground, artificially creating airflow to simulate various complex flight states in the air, and obtaining test data. In order to meet the temperature requirements of some special tests, it is necessary to lay an insulation layer on the surface of the wind tunnel. According to the design requirements of the insulation layer, the temperature of the surface of the insulation layer should not be lower than the local dew point temperature under normal circumstances. Once the insulation layer fails, it will cause the surface temperature of the cavity to drop. During the operation of the wind tu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01K11/32G01M9/06G06F17/10
CPCG01K11/32G01M9/06G06F17/10
Inventor 王斌张文清王强谭志国唐浩李军盖文顾正华
Owner 中国空气动力研究与发展中心设备设计与测试技术研究所
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