Dynamic pressure probe and method for measuring high temp jet dynamic pressure by the probe

Abstract

The invention discloses a dynamic pressure measuring probe and a method for measuring high-temperature jet flow pressure by using the probe, comprising a water-cooled conical pressure probe and a pressure sensor, the water-cooled conical pressure probe includes an outer tube, and the head of the outer tube is opened Sampling hole, the center of the outer tube is provided with a water-air isolation tube, an airflow channel is formed in the inner cavity of the water-air isolation tube, a cooling water channel is formed between the water-air isolation tube and the outer tube, and the end of the outer tube is connected with A pressure sensor, the sensing surface of the pressure sensor corresponds to the air flow channel, and the pressure sensor is sequentially connected to the amplifier and the signal acquisition system through the signal line. Because the pressure sensor is used in the present invention, the residence time of the dynamic pressure measuring probe in the high-temperature jet flow is reduced, the requirement for cooling water inlet water pressure is reduced, the measurement cost is reduced, and the dynamic pressure distribution of the jet flow cross section can be obtained conveniently and quickly , greatly reducing the measurement time.

Description

technical field [0001] The invention relates to a dynamic pressure measuring probe and a method for measuring high-temperature jet flow pressure with the probe. Background technique [0002] As a high-energy beam with high temperature and high enthalpy, thermal plasma jet has been widely used in the fields of aerospace, mechanical processing, metallurgy, chemical industry and bioengineering. The parameters such as temperature and velocity of thermal plasma jet characterize its Important parameter of flow characteristics. Deriving the jet velocity from the measured jet temperature and dynamic pressure data is a commonly used velocity measurement method. The temperature of the plasma jet is generally 3000-15000K. The conventional thermal plasma jet flow pressure measurement is generally carried out through the cooperation of the water-cooled pitot tube and the U-shaped tube (or micromanometer), which belongs to the contact measurement method. That is, the pitot tube is fixed...

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Problems solved by technology

The general Pitot tube is made of an integral structure from the head to the tube body and the Pitot tube support. The head of the Pitot tube is circular, and the cooling water must flow near the head of the Pitot tube, and a dead zone of water flow cannot be formed at the head. , otherwise the pitot tube will be burned out; since the pitot tube pressure measurement is a contact measurement method, it will disturb the measured airflow

In order to reduce the disturbance of the measured air flow, the size of the pitot tube should be reduced as much as possible, so the passage of water in and out is very small, and a high-pressure water pump is required to pressurize the cooling water entering the pitot tube, so as to increase the water flow rate to ensure the cooling effect; Although reducing the size of the pitot tube is the most effective way to reduce the disturbance, however, the special processing technology will increase the price of the pitot tube, making it unaffordable for ordinary buyers; the maximum temperature of the plasma jet often exceeds 10,000 degrees, especially Especially when the gas with high thermal conductivity such as hydrogen is added to the jet gas, the use of the pitot tube needs to be particularly careful, otherwise the head of the pitot tube may be burned and the pitot tube will be scrapped as a whole, which also limits the practical use of the pitot tube. Attempts to use range

At the same time, because the inherent vibration period of the U-shaped tube is very long (on the order of seconds), it cannot respond quickly to the jet flow pressure signal

Therefore, in order to measure the accurate signal of the jet flow pressure, the pitot tube needs to be placed in the high-temperature jet for a long time, which also accelerates the ablation of the pitot tube head to a certain extent, thereby shortening the service life of the pitot tube

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