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CN-121977737-A - Dynamic pressure sensor with 850 ℃ temperature resistance and excellent temperature stability and working method

CN121977737ACN 121977737 ACN121977737 ACN 121977737ACN-121977737-A

Abstract

The invention belongs to the technical field of pressure measurement. The utility model provides a temperature resistant 850 ℃ and excellent dynamic pressure sensor and operating method of temperature stability, by last shell, well shell, the airtight inner chamber that lower shell and diaphragm enclose to and set up the inboard piezoelectricity sensitive component of diaphragm, piezoelectricity sensitive component contains last crystal group and lower crystal group, middle quality piece, the thermal expansion match potsherd at both ends that constitute by high temperature piezoelectricity crystal to through bolt nut subassembly axial pretension. The upper and lower crystal groups are output in opposite polarity and parallel connection, active acceleration compensation is realized, YBP series ceramics are adopted as the thermal expansion matching ceramic plates, high-temperature thermal stress is effectively relieved, all metal parts are sealed by adopting 316L stainless steel and laser welding, internal signals are led to the signal output pins through the electrode plates and nickel wire leads and the alumina ceramic tubes, and the sensor has an active acceleration compensation and thermal expansion matching structure, so that high-stability and high-sensitivity dynamic pressure measurement under a high-temperature severe environment is realized.

Inventors

  • YU FAPENG
  • Zhou Dazhao
  • DUAN XIULAN
  • LI YANLU
  • ZHAO XIAN

Assignees

  • 山东大学

Dates

Publication Date
20260505
Application Date
20260318

Claims (10)

  1. 1. A dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability, characterized in that, The device comprises an upper shell, a middle shell, a lower shell and a diaphragm, wherein the diaphragm, the upper shell, the middle shell and the lower shell form a closed inner cavity; The inner side of the diaphragm is provided with a piezoelectric sensitive component, the piezoelectric sensitive component comprises an upper crystal group and a lower crystal group which are made of high-temperature piezoelectric crystals, a mass block arranged at the upper part of the upper crystal group, and a bolt and nut component which applies pretightening force to the mass block, the upper crystal group and the lower crystal group along the axial direction; The upper end and the lower end of the upper crystal group and the upper end and the lower end of the lower crystal group are respectively clamped with thermal expansion matching ceramic plates; Electrode plates are arranged at two ends of the upper crystal group and the lower crystal group, the electrode plates are connected to a signal output contact pin through nickel wire wires penetrating through the alumina ceramic tube, and the upper shell, the middle shell, the lower shell, the membrane, the mass block and the bolt and nut component are all made of high-temperature resistant alloy and form an integral sealing structure through welding.
  2. 2. The dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability according to claim 1, The upper crystal group is formed by axially superposing two high-temperature piezoelectric crystals and oppositely placing the polarities, and the lower crystal group is formed by axially superposing four high-temperature piezoelectric crystals in turn in a positive-negative alternating order.
  3. 3. The dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability according to claim 1, The thermal expansion coefficient of the thermal expansion matching ceramic sheet is matched with the thermal expansion coefficient of the high-temperature piezoelectric crystal and the high-temperature resistant alloy.
  4. 4. The dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability according to claim 1, The thermal expansion matching ceramic plate adopts YBP series ceramic materials.
  5. 5. The dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability according to claim 1, The alumina ceramic tube axially penetrates through the closed inner cavity along the sensor and is used for insulating and mechanically protecting the nickel wire lead.
  6. 6. The dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability according to claim 1, The high temperature piezocrystal is selected from one or more of RXCOB of monoclinic system and LGT, LGAT, CTGS, CTGAS, gaPO 4 or LN crystal of trigonal system.
  7. 7. The dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability according to claim 1, The ratio beta of the mass block to the equivalent masses of the upper crystal group and the lower crystal group and the equivalent stiffness ratio alpha of the upper crystal group and the lower crystal group meet a preset compensation matching relation so as to ensure that charge signals caused by axial acceleration are basically counteracted between the upper crystal group and the lower crystal group, wherein the preset compensation matching relation is beta=alpha 1。
  8. 8. The dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability according to claim 1, The high-temperature resistant alloy is 316L stainless steel, inconel 600 alloy, inconel 601 alloy or Inconel 718 alloy.
  9. 9. The dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability according to claim 1, The preparation process comprises the steps of sequentially stacking a lower crystal group, a mass block and an upper crystal group on the inner side of a diaphragm, respectively placing thermal expansion matching ceramic plates at the upper end and the lower end of the lower crystal group, applying pretightening force in the axial direction through a bolt and nut assembly to form a piezoelectric sensitive assembly, attaching an electrode plate to the end faces of the upper crystal group and the lower crystal group, connecting one end of a nickel wire with the electrode plate, penetrating the other end of the nickel wire into an alumina ceramic tube, leading out the nickel wire to a signal output contact pin, and finally sealing an upper shell, a middle shell, a lower shell and the diaphragm into a whole through laser welding.
  10. 10. A method for operating a dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability, using the dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability according to any one of claims 1 to 9, comprising the steps of: The sensor is arranged on a pressure interface of the tested equipment through the lower shell, so that the diaphragm directly bears the pressure of the tested medium; When the pressure of the measured medium changes, the diaphragm generates elastic deformation and transmits stress to the piezoelectric sensitive component, and the upper crystal group and the lower crystal group generate charge signals and are output through the nickel wire lead and the signal output pin; When axial acceleration exists, the mass blocks enable the upper crystal group and the lower crystal group to generate acceleration response charges with opposite polarities under the action of inertia, and the acceleration response charges cancel each other in parallel output.

Description

Dynamic pressure sensor with 850 ℃ temperature resistance and excellent temperature stability and working method Technical Field The invention relates to the technical field of pressure measurement, in particular to a dynamic pressure sensor with 850 ℃ temperature resistance and excellent temperature stability and a working method thereof. Background The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. In the aero-engine, gas turbine and high temperature process industries, accurate measurement of transient pressure of a medium (gas, steam or liquid) is required under severe working conditions such as high temperature, high vibration, strong impact and the like, and the method is used for combustion stability evaluation, vibration monitoring and fault diagnosis. The existing high-temperature pressure sensor mostly adopts the principles of strain type, capacitance type and the like, and a cooling cavity, a long impulse pipe or a water cooling structure is arranged at the front end of the sensor, so that the sensitive element can work in a relatively low-temperature environment. The structure has large volume, complex installation and limited response frequency band, and is difficult to meet the requirement of high-temperature dynamic pressure measurement. The piezoelectric pressure sensor utilizes the characteristic that the piezoelectric material generates charge signals when being stressed, does not need to supply power, can be directly arranged in a high-temperature area, and is particularly suitable for high-speed and high-frequency dynamic pressure measurement. However, piezoelectric pressure sensors are very sensitive to axial acceleration and vibration, and their acceleration sensitivity is closely related to the sensor internal mass distribution and stiffness design. The traditional mode for reducing the acceleration influence is mainly achieved by reducing the mass of a diaphragm, improving the structural rigidity and other passive means, the inhibition effect is limited, and the pressure sensitivity is often sacrificed. Aiming at acceleration interference, an active acceleration compensation structure is proposed in the prior art, a mass block is introduced into a sensitive element structure and is matched with the relation between mass and rigidity, so that charge response generated by acceleration is offset in structure, but the existing active acceleration compensation scheme is mostly used in medium-low temperature environments and is difficult to work for a long time in extremely high temperature environments with the temperature being more than 800 ℃, and high temperature environments have higher requirements on thermal stability, thermal expansion matching and airtightness of materials, high temperature alloys such as 316L and the like have good high temperature oxidation resistance and mechanical properties and can be used as sensor shells and mass blocks, and a piezoelectric pressure sensor which organically combines a high temperature piezoelectric crystal, an active acceleration compensation structure, thermal expansion matching ceramic with a high temperature welding sealing shell and can work stably for a long time under the environment with the temperature being about 850 ℃ is still lacking in the existing scheme. Disclosure of Invention In order to overcome the defects that the existing high-temperature pressure sensor needs a complex cooling structure, dynamic response is limited, the piezoelectric sensor is highly sensitive to axial acceleration, and the like, the invention provides the dynamic pressure sensor which is resistant to 850 ℃ and has excellent temperature stability, and the working method thereof, which has an active acceleration compensation and thermal expansion matching structure, and realizes high-stability and high-sensitivity dynamic pressure measurement in a high-temperature severe environment. In order to achieve the above purpose, the present invention adopts the following technical scheme: In a first aspect, the present invention provides a dynamic pressure sensor having a temperature resistance of 850 ℃ and excellent temperature stability. A dynamic pressure sensor with 850 ℃ temperature resistance and excellent temperature stability comprises an upper shell, a middle shell, a lower shell and a diaphragm, wherein the diaphragm, the upper shell, the middle shell and the lower shell enclose a closed inner cavity; The inner side of the diaphragm is provided with a piezoelectric sensitive component, and the piezoelectric sensitive component comprises an upper crystal group and a lower crystal group which are made of high-temperature piezoelectric crystals, a mass block arranged at the upper part of the upper crystal group and a bolt and nut component which applies pretightening force to the mass block, the upper crystal group and the lower crystal group along the axial