Direct-cooling freezing wind tunnel realization method and direct-cooling freezing wind tunnel realization system

A realization method and wind tunnel technology, applied in the field of aerodynamic experiments, can solve the problems of high construction and operation costs, high fan driving power, and increased flow resistance of icing wind tunnels, so as to reduce disturbance and loss, reduce construction and Operating cost, effect of simplified structure

Inactive Publication Date: 2013-02-06
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These devices are all placed in the wind tunnel, which greatly increases the flow resistance, thus requiring a high driving power of the fan, making the icing wind tunnel test a high energy-consuming test project, and the construction and operation costs of the icing wind tunnel are therefore also high. very high

Method used

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  • Direct-cooling freezing wind tunnel realization method and direct-cooling freezing wind tunnel realization system
  • Direct-cooling freezing wind tunnel realization method and direct-cooling freezing wind tunnel realization system
  • Direct-cooling freezing wind tunnel realization method and direct-cooling freezing wind tunnel realization system

Examples

Experimental program
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Effect test

Embodiment 1

[0038] Embodiment 1. Small-scale straight-through icing wind tunnel

[0039] For a small DC wind tunnel, it is assumed that the size of the wind tunnel test section is 0.15x0.15x0.30m, the incoming flow velocity of the wind tunnel is 8m / s, and the flow rate is 0.18m 3 / s, the temperature is 5°C, and the airflow temperature required for the test is -5°C. In this example, low-temperature nitrogen is used as the low-temperature gas. After the low-temperature nitrogen gas is output from the liquid nitrogen tank and vaporized, the temperature rises from -196°C to -193°C due to the loss of cooling capacity of the pipeline. At the same time, it is assumed that the speed of the low-temperature nitrogen entering the wind tunnel from the spray system is the same as the test air flow, then The flow rate of low-temperature nitrogen gas that needs to be introduced is about 0.01m 3 / s, accounting for only about 1 / 18 of the total air flow in the test.

[0040] According to the position of...

Embodiment 2

[0042] Example 2. Small reflux icing wind tunnel

[0043] Assume that the size of the test section of the small-scale recirculation icing wind tunnel described in this example is the same as that of the straight-through wind tunnel in Case 1, that is, 0.15x0.15x0.30m, and that the test air velocity is the same, that is, the same is 8m / s, and the flow rate 0.18m 3 / s, the temperature is 5°C, and the airflow temperature required for the test is -5°C, since the low-temperature airflow in the recirculation wind tunnel can be reused, that is to say, the cold injected into the test airflow will be reused, so in After the test air flow is reduced, the cooling capacity added each time is only the cooling capacity lost due to the heat loss of the equipment, so it can be expected that in the return type wind tunnel, the flow rate of low-temperature gas that needs to be used is smaller, that is, less than 0.01m 3 / s.

[0044] In terms of structural design, the low-temperature gas spray...

Embodiment 3

[0045] Example 3. Large-scale recirculation icing wind tunnel

[0046] Taking the geometry and test parameters of the large-scale icing wind tunnel at the Glenn Center in the United States as a reference, it is assumed that the size of the test section is 2.7x1.8x6m, the maximum wind speed is 179m / s, and the minimum temperature is -40°C. experimenting. Assume that the indoor temperature during the test is 10°C, the test wind speed is 100m / s, and the test temperature is -25°C. After the test airflow is stable, it is assumed that there is 2% of the cooling leakage, and the flow rate of the test airflow is 486m 3 / s. The cooling capacity required at start-up is about 21000J / s, and the nitrogen flow rate for cooling is 100m 3 / s, the nitrogen flow required after stabilization is 2m 3 / s. The total length of the wind tunnel is about 70 meters. Assuming that it takes 1 second to complete the cooling process at startup (that is, the cold air runs around the wind tunnel), 150 lite...

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Abstract

The invention discloses a freezing wind tunnel realization method. Test airflow in the wind tunnel is directly cooled by low-temperature refrigeration gas, moisture in the humid test gas is condensed into liquid drops, and the low-temperature water mist environment required by a freezing test is obtained. The low-temperature refrigeration gas is simultaneously used for lowering the test model surface temperature so as to obtain different parameter combinations among the test airflow temperature, and the liquid drop particle diameter distribution and the model surface temperature to obtain different ice types on the model. The freezing wind tunnel system for realizing the method comprises a fan, a low-temperature gas sprinkling system and a model cooling system, wherein the low-temperature gas sprinkling system is installed on the upper stream of a wind tunnel test section so as to inject low-temperature gas into the test airflow; and the model cooling system is connected with the test model to enable the test model to obtain lower surface temperature. The direct-cooling freezing wind tunnel realization system is higher in heat exchange efficiency, and is simplified in structure, so that not only can direct-cooling freezing wind tunnel realization system be used for a direct-current wind tunnel and a backflow-type wind tunnel and also can be used for transforming the conventional wind tunnel into the freezing wind tunnel.

Description

technical field [0001] The invention belongs to the technical field of aerodynamic experiments, and relates to a method and system for realizing an icing wind tunnel. Background technique [0002] Aircraft icing is the main meteorological factor leading to aircraft accidents. Therefore, the flight airworthiness regulations of various countries (including CCAR25 in my country and FAR25 in the United States) regard aircraft icing as an important airworthiness regulation. From the perspective of scientific research, aircraft icing is a crystallization process in a strong convective environment, and it is the intersection of aircraft aerodynamics and condensed matter physics. Therefore, countries around the world have carried out extensive research on the mechanism and impact of aircraft icing , which uses the icing wind tunnel to study the aircraft icing problem on the ground is a widely used research method and airworthiness verification method. [0003] The wind tunnel is th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01M9/02
Inventor 周华李军俞永辉
Owner TONGJI UNIV
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