Systems and methods for thermal imaging technique for measuring mixing of fluids
Systems and methods for thermal imaging for measuring mixing of fluids are provided. In one embodiment, a method for measuring mixing of gaseous fluids using thermal imaging comprises: positioning a thermal test medium parallel to a direction gaseous fluid flow from an outlet vent of a momentum source, wherein when the source is operating, the fluid flows across a surface of the medium; obtaining an ambient temperature value from a baseline thermal image of the surface; obtaining at least one operational thermal image of the surface when the fluid is flowing from the outlet vent across the surface, wherein the fluid has a temperature different than the ambient temperature; and calculating at least one temperature-difference fraction associated with at least a first position on the surface based on a difference between temperature measurements obtained from the at least one operational thermal image and the ambient temperature value.
1. A method for measuring mixing of gaseous fluids using thermal imaging, the method comprising:
positioning a thermal test medium parallel to a direction of primary flow of a gaseous fluid from an outlet vent of a momentum source, wherein when the momentum source is operating, the gaseous fluid flows across a surface of the thermal test medium;
obtaining an ambient temperature value from a baseline thermal image of the surface when no gaseous fluid is flowing from the outlet vent;
obtaining at least one operational thermal image of the surface when the gaseous fluid is flowing from the outlet vent across the surface, wherein the gaseous fluid has a temperature different than the ambient temperature; and
calculating at least one temperature-difference fraction associated with at least a first position on the surface based on a difference between temperature measurements obtained from the at least one operational thermal image and the ambient temperature value.
2. The method of claim 1 , further comprising:
measuring a speed of the gaseous fluid at the outlet vent; and
calculating a dispersion speed of the gaseous fluid at the first position from a function using the speed of the gaseous fluid at the outlet vent and the temperature-difference fraction.
3. The method of claim 2 , further comprising:
injecting particles into the gaseous fluid flowing from the outlet vent; and
calculating a velocity vector for the gaseous fluid at the first position by correlating the dispersion speed of the gaseous fluid at the first position and a direction of travel observed from the particles.
4. The method of claim 1 , wherein calculating the at least one temperature-difference fraction further comprises calculating:
ⅆ
T
Fraction
(
x
,
y
)
=
ⅆ
T
P
(
x
,
y
)
ⅆ
T
Max
where dT p (x, y) is determined based on a temperature differential at position (x,y) measured from the at least one operational thermal image and the ambient temperature; and
where dT Max is determined based on a temperature differential at the outlet vent measured from the at least one operational thermal image and the ambient temperature.
5. The method of claim 1 , wherein calculating the at least one temperature-difference fraction further comprises calculating:
ⅆ
T
Fraction
(
x
,
y
)
=
ⅆ
T
gas
,
local
(
x
,
y
)
ⅆ
T
gas
,
Max
where dT gas,local (x, y) is determined based on a temperature differential at position (x,y) measured from the at least one operational thermal image and the ambient temperature and further based on performing an iterative algorithm solving an inverse heat conduction problem that determines a local air temperature proximate to position (x,y) on the surface; and
where dT gas,Max is determined based on a temperature differential at the outlet vent measured from the at least one operational thermal image and the ambient temperature and further based on performing the iterative algorithm to determine a local air temperature proximate to the outlet vent.
6. The method of claim 1 , further comprising calculating a mass fraction of the gaseous fluid present at the first position as a function of the at least one temperature-difference fraction.
7. The method of claim 1 , wherein the thermal test medium is further positioned within a return flow into the momentum source and where the surface is further running parallel to the return flow, the method further comprising:
measuring a speed of the return flow at an inlet vent into the momentum source; and
calculating a recirculation fraction at the inlet vent from a function of the temperature-difference fraction and the speed of the return flow at the inlet vent.
8. The method of claim 1 , wherein either the surface of the thermal test medium comprises either a continuous surface, or thermal test medium comprises a mesh material.
9. The method of claim 1 , wherein calculating the at least one temperature-difference fraction further comprises:
performing an iterative algorithm solving an inverse heat conduction problem that determines a local air temperature proximate to the first position on the surface.
10. The method of claim 1 , wherein the momentum source comprises one of an air conditioning system, a fan, or a compressed air source.
11. A system for measuring mixing of gaseous fluids using thermal imaging, the system comprising:
a momentum source having at least one output vent from which a gaseous fluid flows;
a thermal test medium positioned within a flow of the gaseous fluid and having a surface running parallel to the primary direction of flow; and
a thermal imaging device positioned take thermal images of the surface, the thermal imaging device coupled to a processor;
wherein the processor obtains at least one operational thermal image of the surface when the gaseous fluid is flowing from the outlet vent across the surface, wherein the gaseous fluid has a temperature different than an ambient temperature value for the surface measured when no gaseous fluid is flowing from the outlet vent; and
wherein the processor calculates at least one temperature-difference fraction associated with at least a first position on the surface based on a difference between temperature measurements obtained from the at least one operational thermal image and the ambient temperature value.
12. The system of claim 11 , further comprising:
at least one velocity probe positioned at the output vent, the at least one velocity probe coupled to the processor;
wherein the processor calculates a dispersion speed of the gaseous fluid at the first position from a function of the temperature-difference fraction and a speed of the gaseous fluid at the outlet vent as measured by the at least one velocity probe.
13. The system of claim 12 , further comprising:
an apparatus configured to inject particles into the gaseous fluid at the outlet vent; and
wherein the processor calculates a velocity vector for the gaseous fluid at the first position by correlating the dispersion speed of the gaseous fluid at the first position and a direction of travel observed from the particles.
14. The system of claim 11 , wherein the processor calculates the at least one temperature-difference fraction based on the equation:
ⅆ
T
Fraction
(
x
,
y
)
=
ⅆ
T
P
(
x
,
y
)
ⅆ
T
Max
where dT p (x, y) is determined based on a temperature differential at position (x,y) measured from the at least one operational thermal image and the ambient temperature; and
where dT Max is determined based on a temperature differential at the outlet vent measured from the at least one operational thermal image and the ambient temperature.
15. The system of claim 11 , wherein the processor calculates the at least one temperature-difference fraction based on the equation:
ⅆ
T
Fraction
(
x
,
y
)
=
ⅆ
T
gas
,
local
(
x
,
y
)
ⅆ
T
gas
,
Max
where dT gas,local (x, y) is determined based on a temperature differential at position (x,y) measured from the at least one operational thermal image and the ambient temperature and further based on an iterative algorithm that solves an inverse heat conduction problem that determines a local air temperature proximate to position (x,y) on the surface; and
where dT gas,Max is determined based on a temperature differential at the outlet vent measured from the at least one operational thermal image and the ambient temperature and further based on an iterative algorithm that determines a local air temperature proximate to the outlet vent.
16. The system of claim 11 , further comprising:
an inlet vent providing a return flow to the momentum source, wherein the thermal test medium is further positioned within the return flow and where the surface is further running parallel to the return flow; and
at least one velocity probe positioned at the inlet vent, the at least one velocity probe coupled to the processor;
wherein the processor calculates a recirculation fraction at the inlet vent from a function the temperature-difference fraction and a speed of the return flow at the inlet vent as measured by the at least one velocity probe.
17. The system of claim 11 , wherein the processor calculates a mass fraction of the gaseous fluid present at the first position as a function of the at least one temperature-difference fraction.
18. The system of claim 11 , wherein the processor calculates the at least one temperature-difference fraction further based on an iterative algorithm solving an inverse heat conduction problem that determines a local air temperature proximate to the first position on the surface.
19. The system of claim 11 , wherein either the surface of the thermal test medium comprises either a continuous surface, or thermal test medium comprises a mesh material.
20. The system of claim 11 , wherein the momentum source comprises one of an air conditioning system, a fan, or a compressed air source.