Electric heating element for large-flow high-temperature high-pressure high-speed gas environment and processing method

Abstract

The invention belongs to the technical field of hypersonic wind tunnel test equipment, and discloses an electric heating element for a large-flow high-temperature high-pressure high-speed gas environment and a processing method. The electric heating element adopts a clamping plate type structure and comprises a plurality of electric heating tubes arranged in parallel, an upper surface clamping plate covering the upper surfaces of the electric heating tubes, a lower surface clamping plate covering the lower surfaces of the electric heating tubes, and a protection box covering the neutral ends of the electric heating tubes. According to the machining method, an upper surface clamping plate, an electric heating pipe and a lower surface clamping plate are clamped and folded through a tool, then a pin penetrates through the upper surface clamping plate and the lower surface clamping plate, the upper surface clamping plate, the lower surface clamping plate and a protection box are welded through argon arc welding, and the electric heating element becomes a square body. The electric heating element adopts a clamping plate type structure, the strength of the electric heating element can be improved, the contact area is increased, the heat exchange efficiency is improved, and the wind tunnel test quality and efficiency are ensured. The processing method is simple and reliable, high in precision and small in deformation.

Description

technical field [0001] The invention belongs to the field of hypersonic wind tunnel test equipment, and in particular relates to an electric heating element and a processing method used in a high-flow, high-temperature, high-pressure, and high-speed gas environment. Background technique [0002] In a conventional hypersonic wind tunnel using air as the test medium, due to the extremely high gas flow velocity, reaching Mach number 5 to Mach number 10, the violent expansion of the gas flow through the nozzle will cause water vapor and carbon dioxide to condense, resulting in irregularities in the flow field. The uniformity makes the test data inaccurate, which is not allowed in the hypersonic wind tunnel aerodynamic test. Therefore, in a conventional hypersonic wind tunnel with a large flow of high-speed air as the medium, it is necessary to install a regenerative heater to heat the airflow to the required anti-condensation temperature. [0003] Conventional hypersonic wind t...

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Problems solved by technology

[0005] The direct application of traditional electric heating tubes to hypersonic wind tunnel regenerative heaters has the following disadvantages: a. Under the conditions of large flow, high pressure, and high speed, the traditional electric heating tubes are not strong enough, and they are easy to deform and bend, resulting in damage to the electric heating tubes ; b. The contact area between the electric heating tube and the heat storage element is small, the heat conduction area is small, and the heat transfer efficiency is low, resulting in a low heating rate of the heat storage element, the airflow temperature cannot reach the anti-condensation temperature, and the electric heating tube is overheated and damaged; c. The temperature control thermocouple of the tube is fixed on the surface of the electric heating tube with a clamp. Under repeated impacts, the insulating ceramics are easily damaged and lead to insulation failure; e. It is difficult to install and fix multiple electric heating tubes inside the heater. Normal use affects the quality and efficiency of wind tunnel tests

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