Method and measuring apparatus for determining physical properties of gas
AssigneeMems AG
InventorsPhilippe Pretre, Andreas Kempe, Tobias Suter
Life of this patent
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Abstract
A method using a gas reservoir and a critical nozzle for determining physical properties and/or quantities relevant to combustion of gas or gas mixtures, the method includes: flowing a gas or gas mixture under pressure from the gas reservoir through the critical nozzle; measuring pressure drop in the gas reservoir as a function of time; determining a gas property factor (Γ*), dependent on physical properties of the gas or gas mixture, based on the measured values of the pressure drop; and determining a desired physical property or quantity relevant to combustion based on the gas property factor (Γ*) through correlation.
Claims24
A method for determining physical properties and/or quantities relevant to combustion of gas and/or gas mixtures, the method comprising:
- flowing a gas or gas mixture from a gas reservoir or into a gas reservoir with the gas or gas mixture flowing under pressure through a critical nozzle and past a microthermal sensor, wherein the same mass flow is applied to the critical nozzle and the microthermal sensor;
- measuring pressure drop or pressure increase respectively in the gas reservoir as a function of time;
- determining a first gas property factor (Γ*), which is dependent on a first group of physical properties of the gas and/or gas mixture, on the basis of measured values of the pressure drop or pressure increase;
- determining a second gas property factor (Γ), which is dependent on a second group of physical properties of the gas or gas mixture, from a flow signal generated by the microthermal sensor;
- determining the thermal conductivity (λ) of the gas and/or gas mixture using the microthermal sensor;
- and
- determining a physical property and/or quantity relevant to combustion from the first and second gas property factor (Γ*, Γ) and the thermal conductivity (λ) through correlation.
A method to use a gas reservoir and a critical nozzle for determining physical properties and/or quantities relevant to combustion of gas or gas mixtures, the method comprises:
- flowing a gas or gas mixture from the gas reservoir or into the gas reservoir with the gas or gas mixture flowing under pressure through the critical nozzle, and, in the case the gas or gas mixture is flowing from the gas reservoir, with a decreasing mass flow of the gas or gas mixture when pressure is decreasing in the gas reservoir;
- measuring the pressure drop or pressure increase respectively in the gas reservoir as a function of time, wherein a nozzle inlet pressure of the critical nozzle is higher than a critical pressure of the critical nozzle during the measuring of the pressure drop or pressure increase respectively in the gas reservoir;
- determining a gas property factor (Γ*), which is dependent on the physical properties of the gas or gas mixture, on the basis of measured values of the pressure drop or pressure increase;
- and
- determining a desired physical property or quantity relevant to combustion on the basis of the gas property factor (Γ*) through correlation.
A method to use a gas reservoir and a critical nozzle for determining physical properties and/or quantities relevant to combustion of gas or gas mixtures, the method comprises:
- flowing a gas or gas mixture from the gas reservoir or into the gas reservoir with the gas or gas mixture flowing under pressure through the critical nozzle, and, in the case the gas or gas mixture is flowing from the gas reservoir, with a decreasing mass flow of the gas or gas mixture when pressure is decreasing in the gas reservoir;
- measuring the pressure drop or pressure increase respectively in the gas reservoir as a function of time;
- determining a gas property factor (Γ*), which is dependent on the physical properties of the gas or gas mixture, on the basis of measured values of the pressure drop or pressure increase;
- and
- determining a desired physical property or quantity relevant to combustion on the basis of the gas property factor (Γ*) through correlation,
- wherein a polytropic index (n) is determined on the basis of measured values of the pressure drop or pressure increase respectively, and/or wherein the physical property and/or quantity relevant to combustion through correlation is further determined on the basis of the polytropic index (n).
Dependencies are inferred from the claim text.