Methods and systems for acoustic determination of gas composition

1 . A method comprising:

propagating acoustic waves through a gas;

obtaining, using each of a plurality of pressure sensors disposed adjacent to the gas, each of a plurality of pressure signals in response to the acoustic waves;

determining a dispersion relation of the acoustic waves using the plurality of pressure signals;

determining a speed of sound of the acoustic waves using the dispersion relation;

determining an attenuation of the acoustic waves using the dispersion relation; and

determining, with a computational model, a composition of the gas using the speed of sound and the attenuation.

2 . The method of claim 1 , wherein determining the dispersion relation comprises applying a two-dimensional Fourier transform to the plurality of pressure signals.

3 . The method of claim 1 , wherein the computational model comprises a machine learning model comprising an artificial neural network.

4 . The method of claim 1 , further comprising:

determining a dispersion of the acoustic waves using the dispersion relation; and

determining, with the computational model, the composition of the gas using the speed of sound, the attenuation, and the dispersion.

5 . The method of claim 1 , further comprising:

obtaining, using a first sensor, a pressure of the gas;

obtaining, using a second sensor, a temperature of the gas; and

determining, with the computational model, that determines the composition of the gas using the speed of sound, the attenuation, the pressure, and the temperature.

6 . The method of claim 1 :

wherein the plurality of pressure sensors is disposed on a sample chamber that contains the gas.

7 . The method of claim 6 , wherein propagating the acoustic waves through the gas comprises

generating, using a shockwave generator, the acoustic waves.

8 . The method of claim 1 , further comprising opening or closing a control valve within a pipe that the gas flows through in response to the composition of the gas.

9 . A system comprising:

a plurality of pressure sensors disposed adjacent to a gas and configured to obtain a plurality of pressure signals in response to acoustic waves; and

a pressure control system comprising a processor and a memory, the pressure control system configured to:

receive, from each of the plurality of pressure sensors, each of the plurality of pressure signals,

determine a dispersion relation of the acoustic waves using the plurality of pressure signals,

determine a speed of sound of the acoustic waves using the dispersion relation,

determine an attenuation of the acoustic waves using the dispersion relation, and

determine, with a computational model, a composition of the gas using the speed of sound and the attenuation.

10 . The system of claim 9 , further comprising:

a first sensor configured to obtain a pressure of the gas; and

a second sensor configured to obtain a temperature of the gas,

wherein the pressure control system is configured to determine, with the computational model, the composition of the gas using the speed of sound, the attenuation, the pressure, and the temperature.

11 . The system of claim 9 , further comprising:

a sample chamber configured to contain the gas,

wherein the plurality of pressure sensors is disposed along the sample chamber.

12 . The system of claim 11 , further comprising:

a shockwave generator configured to generate the acoustic waves.

13 . A non-transitory computer-readable memory comprising computer-executable instructions stored thereon that, when executed on a processor, cause the processor to perform:

receiving, from each of a plurality of pressure sensors in response to acoustic waves propagating through a gas, each of a plurality of pressure signals;

determining a dispersion relation of the acoustic waves using the plurality of pressure signals;

determining a speed of sound of the acoustic waves using the dispersion relation;

determining an attenuation of the acoustic waves using the dispersion relation; and

determining, with a computational model, a composition of the gas using the speed of sound and the attenuation.

14 . The non-transitory computer-readable memory of claim 13 , further causing the processor to perform:

determining a dispersion of the acoustic waves using the dispersion relation; and

determining, with the computational model, the composition of the gas using the speed of sound, the attenuation, and the dispersion.

15 . The method of claim 1 , wherein determining the speed of sound of the acoustic waves comprises:

determining a power ridge within the dispersion relation;

determining an average velocity along the power ridge; and

determining the speed of sound of the acoustic waves using the average velocity.

16 . The method of claim 1 , wherein determining the attenuation of the acoustic waves comprises:

determining a power ridge within the dispersion relation;

determining a slope of the power ridge; and

determining the attenuation of the acoustic waves using the slope.

17 . The method of claim 4 , wherein determining the dispersion of the acoustic waves comprises:

determining a power ridge within the dispersion relation;

determining an inflection point of the power ridge; and

determining the dispersion of the acoustic waves using the inflection point.

18 . The method of claim 1 , wherein the acoustic waves have a frequency below 20 kilohertz.

19 . The method of claim 3 , wherein determining, with the computational model, the composition of the gas, comprises:

inputting the speed of sound and the attenuation into the trained machine learning model; and

predicting the composition of the gas from the trained machine learning model in response to the speed of sound and the attenuation.