Design of wind speed sensor for the cabin of manned spacecraft

摘要

When manned spacecraft in-orbit flight, the cabin air in a state of micro gravity. The flow and heat exchange of the cabin need fan to forced convection. The wind speed measurement of manned spacecraft cabin air is valuable for fan arrangement and heat exchange design. The wind speed sensor uses the principle of heat dissipation. The sensitive component is composed of a glass spheres, electric heated wire and thermocouple. The thermocouple passes through spiral electric heated wire, and the end of thermocouple in the spiral electric heated wire center. The above structure is encapsulated in glass spheres with a diameter of less than 1mm, thereby constituting the sensitive component. To improve the sensitivity of sensitive component, the glass spheres packaging can add another thermocouple. Circuit of the sensor is composed of a constant current source circuit and a thermocouple voltage amplification circuit. The glass spheres is heating by electric heated wire when a constant current through the electric heated wire. In no wind condition, the glass spheres temperature constant about 150°C. The glass spheres temperature change as the wind speed change. Its obtain wind speed by measure the temperature of the glass spheres with the thermocouple. Through theoretical analysis, it obtains the relationship between the output voltage and the wind speed. Through ANSYS simulation, it obtains the dynamic characteristics of the sensor. Through the test of the sensor, its characteristics conform to the result of theoretical analysis. The sensor is high in measuring precision, meanwhile, it has the advantages of small volume, light weight and high reliability. The sensor can satisfy the wind speed measurement of manned spacecraft cabin.