US 12,264,949 B2 · Gas flow estimation method, hole diameter estimation method, gas flow rate estimation device, and hole diameter estimation device

Abstract

A flow rate of a gas is determined based on a predetermined relational expression including, as parameters: the flow rate of the gas; diameter and length of a hole; upstream and downstream pressures; and temperature, molecular weight, viscosity coefficient, and specific heat ratio of the gas. Additionally, setting conditions for a type and temperature of the gas, the length of the hole, and the pressures upstream and downstream from the hole are set; the relational expression is used to obtain the correspondence relationship between the diameter of the hole and the flow rate of the gas flowing through the hole; an approximation function approximating the obtained correspondence relationship is determined; the flow rate of a gas passing through a test piece having a hole of an unknown diameter is measured; and the diameter of the hole is estimated, based on the measured flow rate and the approximation function.

Claims12

Dependent claims

A gas flow rate estimation method, comprising:

determining a flow rate of gas flowing through a hole by a computation unit, based on a type of the gas flowing through the hole, pressures upstream and downstream from the hole, and information about the hole, wherein
the flow rate of the gas is determined by the computation unit, regardless of a state of flow of the gas, from a molecular weight, a viscosity coefficient, and a specific heat ratio of the gas, a diameter and a length of the hole, and the upstream and downstream pressures of the gas flowing through the hole, based on a predetermined relational expression including, as parameters, all of the flow rate of the gas, the diameter of the hole, the length of the hole, the upstream and downstream pressures of the hole, a temperature of the gas, the molecular weight of the gas, the viscosity coefficient of the gas, and the specific heat ratio of the gas, and
the predetermined relational expression includes Qc represented by the following expression:
Q
C
=
Q
CF
′
(
Q
CF
′
Q
TB
)
2
+
1
·
(
Q
CF
′
Q
VL
⁢
Q
CF
′
/
Q
TB
)
2
+
1
)
2
+
1
,
where Qc is the flow rate of the gas under assumption of continuous flow, QVL is the flow rate of the gas under assumption of laminar flow, QTB is the flow rate of the gas under assumption of turbulent flow, and QCF′ is the flow rate of the gas under assumption of compressible flow.

40 more elements

A hole diameter estimation method for determining a diameter of a hole by a computation unit, based on a type and a temperature of gas flowing through the hole, pressures upstream and downstream from the hole, and a flow rate of the gas flowing through the hole, said hole diameter estimation method comprising:

a step of obtaining a correspondence relationship between the diameter of the hole and the flow rate of the gas flowing through the hole, by setting conditions of the type and temperature of the gas, a length of the hole, and the upstream and downstream pressures of the hole, and using a predetermined relational expression under the setting conditions;
a step of determining an approximation function approximating the correspondence relationship, which is obtained under the setting conditions, between the diameter of the hole and the flow rate of the gas flowing through the hole;
a step of providing a test piece having a hole of an unknown diameter;
a step of measuring the flow rate of the gas passing through the hole of the test piece under the setting conditions;
and
a step of estimating the diameter of the hole by the computation unit, based on the measured flow rate of the gas and the approximation function, wherein
the predetermined relational expression includes Qc represented by the following expression:
Q
C
=
Q
CF
′
(
Q
CF
′
Q
TB
)
2
+
1
·
(
Q
CF
′
Q
VL
⁢
Q
CF
′
/
Q
TB
)
2
+
1
)
2
+
1
,
where Qc is the flow rate of the gas under assumption of continuous flow, QVL is the flow rate of the gas under assumption of laminar flow, QTB is the flow rate of the gas under assumption of turbulent flow, and QCF′ is the flow rate of the gas under assumption of compressible flow.

44 more elements

A gas flow rate estimation device for determining a flow rate of gas flowing through a hole from a type of the gas flowing through the hole, pressures upstream and downstream from the hole, and information about the hole, said gas flow rate estimation device comprising:

a gas type setting unit setting a molecular weight of the gas, a viscosity coefficient of the gas, and a specific heat ratio of the gas, based on a selected type of the gas;
a gas temperature setting unit setting a temperature of the gas;
a hole length setting unit setting a length of the hole;
a hole diameter setting unit setting a diameter of the hole;
a pressure setting unit setting the pressures upstream and downstream from the hole;
a storage unit storing a relational expression including, as parameters, all of the flow rate of the gas, the diameter of the hole, the length of the hole, the upstream and downstream pressures of the hole, a temperature of the gas, the molecular weight of the gas, the viscosity coefficient of the gas, and the specific heat ratio of the gas;
and
a computation unit using the relational expression stored in the storage unit to calculate the flow rate of the gas flowing through the hole, based on the molecular weight, the viscosity coefficient and the specific heat ratio of the gas of the type set by the gas type setting unit, the temperature set by the gas temperature setting unit, the length of the hole set by the hole length setting unit, the diameter of the hole set by the hole diameter setting unit, and the upstream and downstream pressures of the hole set by the pressure setting unit, wherein
the relational expression includes Qc represented by the following expression:
Q
C
=
Q
CF
′
(
Q
CF
′
Q
TB
)
2
+
1
·
(
Q
CF
′
Q
VL
⁢
Q
CF
′
/
Q
TB
)
2
+
1
)
2
+
1
,
where Qc is the flow rate of the gas under assumption of continuous flow, QVL is the flow rate of the gas under assumption of laminar flow, QTB is the flow rate of the gas under assumption of turbulent flow, and QCF′ is the flow rate of the gas under assumption of compressible flow.

46 more elements

A hole diameter estimation device for estimating a diameter of a hole formed in a test piece, said hole diameter estimation device comprising:

a gas type setting unit setting a molecular weight of gas, a viscosity coefficient of the gas, and a specific heat ratio of the gas, based on a selected type of the gas;
a gas temperature setting unit setting a temperature of the gas;
a hole length setting unit setting a length of the hole;
a pressure setting unit setting pressures upstream and downstream from the hole;
a storage unit storing an approximation function approximating a correspondence relationship between the diameter of the hole and a flow rate of the gas flowing through the hole, said correspondence relationship being obtained by using a relational expression under setting conditions of the molecular weight, the viscosity coefficient and the specific heat ratio of the gas of the type set by the gas type setting unit, the temperature set by the gas temperature setting unit, the length of the hole set by the hole length setting unit, and the upstream and downstream pressures of the hole set by the pressure setting unit;
a flow rate measurement unit measuring the flow rate of the gas passing through the hole of the test piece in a state where the upstream and downstream pressures set in the pressure setting unit are generated inside and outside the test piece, by placing the test piece inside the flow rate measurement unit and using the selected type of the gas at the temperature set in the gas temperature setting unit;
and
a computation unit calculating the diameter of the hole, based on the flow rate measured by the flow rate measurement unit under the setting conditions and the approximation function stored in the storage unit, wherein
the relational expression includes Qc represented by the following expression:
Q
C
=
Q
CF
′
(
Q
CF
′
Q
TB
)
2
+
1
·
(
Q
CF
′
Q
VL
⁢
Q
CF
′
/
Q
TB
)
2
+
1
)
2
+
1
,
where Qc is the flow rate of the gas under assumption of continuous flow, QVL is the flow rate of the gas under assumption of laminar flow, QTB is the flow rate of the gas under assumption of turbulent flow, and QCF′ is the flow rate of the gas under assumption of compressible flow.

46 more elements

Dependencies are inferred from the claim text.

Gas flow estimation method, hole diameter estimation method, gas flow rate estimation device, and hole diameter estimation device

Life of this patent

Gas flow estimation method, hole diameter estimation method, gas flow rate estimation device, and hole diameter estimation device

Life of this patent

Abstract

Claims12