Thermo-acoustic heat engine acoustic field monitoring method monitoring system

Abstract

The invention discloses a sound field monitoring method and a monitoring system for a thermoacoustic engine. The method comprises the follow steps of: (1) measuring the sound pressure of the working fluid in a thermoacoustic system tube with at least two sound pressure sensors; (2) reconstructing the sound pressure distribution of the fluid in the tube with the sound pressure measured by any two sound pressure sensors; (3) reconstructing the local velocity distribution of the fluid in the tube; (4) reconstructing the acoustic impedance distribution inside the tube; (5) reconstructing the reflection factor distribution inside the tube; and (6) reconstructing the sound intensity distribution inside the tube. The monitoring system comprises at least two pressure measuring holes opened on the wall of a measured tube of the thermoacoustic engine, and at least two sound pressure sensors are sealed in the pressure measuring holes corresponding to the pressure measuring holes; the sound pressure sensor is connected with a corresponding signal conditioner, the output signal of the signal conditioner is transmitted to a signal processing device, and the processed result is output and displayed on an output display apparatus. The invention has the advantages of real-time diagnosis and monitoring, and high accuracy.

Description

technical field [0001] The invention relates to thermoacoustic heat engine technology, in particular to a sound field reconstruction method and monitoring system of a thermoacoustic heat engine. Background technique [0002] Thermoacoustic heat engine, including thermoacoustic engine and thermoacoustic refrigerator, is a new type of heat engine with no moving parts and is friendly to the environment. It has received extensive attention since its inception. A thermoacoustic heat engine system usually consists of a thermoacoustic system pipe section, a regenerator, a heat exchanger, and a high-pressure gas working medium. The acoustically driven thermoacoustic refrigerator also includes sound source components. [0003] By setting a sound pressure sensor at a certain point on the pipe wall of the thermoacoustic heat engine, the sound pressure of the oscillating fluid at that point can be measured. In order to further study the law of the sound field inside the thermoacoustic ...

AI Technical Summary

Problems solved by technology

[0005] First of all, the laser Doppler velocimeter can only measure the particle flow velocity of the fluid in the tube when the tube wall can transmit light. In order to use this measurement method in the existing thermoacoustic device, it must be structurally modified. The transparent glass tube replaces the original metal tube section. The introduction of the glass tube limits the pressure bearing and sealing performance of the system, which has a serious impact on the sound field of the system under test. Due to the difference between the experimental tube and the actual thermoacoustic system tube, so Availability of test results is significantly affected

[0006] Secondly, this technology is based on the direct measurement of sound pressure and flow velocity at multiple points. The measuring points are several discrete points in space. There is no position for measuring points in the pipe section, and the values ​​of two adjacent points can only be used for interpolation. The accuracy is affected by the number of measuring points

In other words, in order to improve the measurement accuracy, the number of measurement points must be increased, which will inevitably increase the cost of the measurement system and increase the measurement time.

[0007] Furthermore, this technique cannot be used for real-time measurement of the sound field

Due to the use of laser Doppler velocimeters to measure the particle flow velocity of each measuring point sequentially, it is impossible to measure the particle flow velocity of all measuring points at the same time

For thermoacoustic devices that operate stably, this sequential measurement is feasible, but for devices that operate in an unsteady state, in order to measure the instantaneous sound field, it is required to measure the flow velocity of each point particle in the sound field synchronously, and this method is no longer applicable.

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