Micro-thrust measurement device with thermal protection system

Abstract

The invention discloses a micro-thrust measurement device with a thermal protection system. The micro-thrust measurement device comprises a target system, a displacement sensor system, a target mounting block and a thermal protection system. In the target system, an elastic beam and the target mounting block are connected and positioned through vertical angle aluminium, and the perpendicularity of the elastic beam is guaranteed; and a target is mounted at the bottom end of the elastic beam. In the displacement sensor system, a sensor mounting rod is vertically arranged, the top end of the sensor mounting rod is fixedly connected with the bottom face of the target mounting block, and a displacement sensor is mounted at the bottom end of the sensor mounting rod through a sensor mounting plate. In the thermal protection system, thermal protection to the elastic beam is achieved through two sections of ceramic tubes, and meanwhile the thermal protection to the sensor is achieved through a sensor protection cover. The micro-thrust measurement device has the advantages that the entire measurement device is made to achieve integration through the target mounting block, so that the distance between the measurement device and an engine is very convenient to adjust, and even continuous automatic adjustment is achieved in the measuring process. Meanwhile, the measurement device is subjected to sealing protection to the greatest degree through the thermal protection system.

Description

technical field [0001] The invention belongs to the technical field of micro-thrust thrusters in space, and specifically relates to a micro-thrust measurement device with a thermal protection system, which is a part of the micro-thrust measurement system. Background technique [0002] With the development of electric propulsion technology, more and more electric thrusters have been designed, but the thrust of many electric thrusters is in the mN level, and it is difficult to accurately measure such a small thrust by conventional thrust measurement methods. The thrust is a very important parameter of the thruster. If the thrust cannot be determined, some important performance parameters of the thruster, such as specific impulse, will also be uncertain, which will bring great trouble to the practical application of the thruster. [0003] In order to accurately measure the thrust of the electric thruster, a micro-thrust measurement system has been designed. The micro-thrust me...

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Problems solved by technology

The premise of using the single pendulum model is that the length of the target suspension device is large enough relative to the characteristic length of the target surface, so this measurement device requires a large space, and the suspended target must have a rotating shaft, and the sliding of the rotating shaft Friction will have a certain influence on the measurement results

And the thruster targeted by this measurement device is a miniature cold air thruster, the gas ejected is nitrogen, and the temperature is relatively low, while the additional field plasma thruster ejects a high-temperature plume, and the working conditions are very harsh

In addition, the sensor used for displacement measurement in this system is an eddy current displacement sensor, which is difficult to work normally in the strong electromagnetic environment of the additional field plasma thruster plume

In foreign countries, there are target-thrust measurement devices for ion thrusters, but foreign target-thrust measurement devices use laser reflection when measuring the displacement of the target. This method is easily interfered by the strong light emitted by the engine.

Moreover, the target and the displacement measuring device in this system are separated, and the thrust frame needs to be recalibrated every time the position of the target is moved.

So these devices are not suitable for the thrust measurement of the additional field plasma thruster

[0005] Moreover, in the thrust measurement device of the shooting method, the power of the thruster is usually relatively large, and as a result, the heat release amount of the engine plume is very large, so the amount of heat radiation received by the elastic beam is very large

If it is not thermally protected, the temperature of the beam will rise rapidly, as a result, the elastic coefficient of the beam will change significantly, and the measurement results will have a large error

In addition, the displacement measuring device also has requirements on the working temperature, and it cannot work normally after exceeding a certain temperature.

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