Thermal film flow field sensing system with flexible intelligent sheath and application of system

Abstract

The invention belongs to the flow velocity sensor field and discloses a thermal film flow field sensing system with a flexible intelligent sheath and application of the system. The system comprises asubstrate, temperature measuring resistor units, a heating resistor unit and an extraction electrode; the heating resistor unit and the temperature measuring resistor units are attached to the flexible substrate; a plurality of groups of temperature measuring resistor units are provided and are uniformly and circumferentially arranged on the flexible substrate and distributed around the heating resistor unit; each of the heating resistor unit and the temperature measuring resistor units is of a spiral stretchable structure; and the temperature measuring resistor units and the heating resistorunit are connected with the lead electrode. With the thermal film flow field sensing system with the flexible intelligent sheath and the application of the system of the present invention adopted, 360-degree two-dimensional flow velocity measurement can be realized. According to the sensor, the polyimide flexible substrate is adopted; the temperature measuring resistor unit is of a self-similar structure; and therefore, the effective contact area of the system with wind speed can be improved, the sensitivity of the sensor can be improved, and the sensor can be conveniently attached onto the curved surface of a complex aircraft surface.

Description

Technical field [0001] The invention belongs to the field of flow rate sensors, and more specifically, relates to a flexible and intelligent skinned thermal film flow field sensing system and its application. Background technique [0002] Velocity measurement plays a very important role in aerospace, oil, natural gas, chemical and pharmaceutical industries, especially in the aviation field. The measurement of the velocity and flow direction of the aircraft surface is helpful for the aircraft to learn the changes of external aerodynamic parameters in time, so as to provide feedback Adjust the flight attitude, etc., to ensure the smooth and safe flight of the aircraft. At present, the methods used to measure the flow velocity of aircraft are often Pitot tube method and thermal sensor method. Pitot tube method is a common method for measuring flow velocity on fighter aircraft. The technology is mature, but the shortcomings are also obvious. It will generate shock waves and interfer...

AI Technical Summary

Problems solved by technology

Thermal sensors are divided into two types: hot-wire and hot-film. The hot-wire sensor is directly measured by hot wire, so it is easy to be polluted during the measurement process, which affects heat transfer and reduces measurement accuracy. Therefore, hot-film sensors are often used.

[0003] At present, micro-electromechanical system technology (MEMS) is mostly used for the production of hot-film wind speed sensors, and corresponding hot-film wind speed sensors are produced on silicon wafers (ceramic or glass) using this process, and the produced hot-film wind speed sensors The wind speed and direction sensor has the advantages of good stability, high measurement accuracy and no influence of pressure. However, due to the use of hard and brittle substrate materials such as silicon, it is fragile during the production process, and it is not suitable for installation on complex curved surfaces after production, which is inconvenient for aircraft. Surface Velocity and Direction Measurement

Moreover, with the introduction of intelligent skin technology, it is required that the sensor can be integrated into the surface of the aircraft for real-time measurement. The current silicon-based hot-film sensor obviously cannot meet the requirements. Therefore, how to design and manufacture a flexible and high-precision hot-film wind speed and direction sensor is suitable Velocity measurement on the surface of the aircraft has become a very critical issue

In order to solve this problem, corresponding solutions have been mentioned in many literatures. For example, the team of Teacher Zhu Rong from Tsinghua University designed and manufactured a hot film sensor based on a flexible polyimide substrate, and successfully applied the sensor in a small wireless sensor. On the man-machine, the sensor has a simple structure, but it can only measure in two directions, and cannot give the angle of any incoming wind speed, and the thermal film is too large, so the accuracy needs to be improved; An arrayed one-way hot film sensor was fabricated on the substrate, and the sensor was used to measure the flow velocity and shear stress on the surface of the wind tunnel model. The one-way measurement results were good, but the sensor could neither measure the wind direction at any angle, and the hot film and The connecting wires exist due to technological reasons. Under the high-frequency vibration brought by the wind, the connection is easy to disconnect and fail. At the same time, because the measurement circuit does not implement isothermal control, the power consumption of the entire sensor measurement system is very large.

Patents CN103592461A and CN101349708A respectively announced the preparation and measurement of a two-dimensional flow velocity vector sensor. The sensor manufacturing process is simple, and the measurement circuit uses a constant temperature difference design, which reduces power consumption and ensures stable output. However, the two The sensor is not flexible, and the connection leads are crossed, which will affect the distribution of the flow field during measurement, making the final measurement result inaccurate

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