Measurement of liquid fraction dropout using micropatterned surfaces
Accurate, real-time detection of dew point of a gaseous sample can be accomplished using the systems and techniques described herein. A gaseous sampling chamber defining an interior volume includes a patterned structure having a roughened surface exposed to the gaseous sampling chamber. The patterned structure includes an open volume accessible by the roughened surface, for example, representing at least about 10% of the interior volume of the gaseous sampling chamber. An illumination source is configured to illuminate at least a portion of the patterned structure. A light detector is configured to receive at least a portion of illumination returned from the patterned structure. A condensate detector is configured to determine a presence of a condensate on the roughened surface in response to an optical property of the patterned surface as modified by the presence of dew.
1. A condensate detector, comprising:
a gaseous sampling chamber defining an interior volume;
a patterned structure forming a roughened surface at least partially exposed to the interior surface of the gaseous sampling chamber, the patterned structure comprising an open volume accessible by the roughened surface, the open volume being at least about 10% of the interior volume of the gaseous sampling chamber;
an illumination source configured to illuminate at least a portion of the patterned structure;
a light detector configured to receive at least a portion of illumination returned from the patterned structure; and
a condensate detector in communication with at least the light detector, and configured to determine a presence of a condensate on the roughened surface in response to returned illumination received at the light detector.
2. The condensate detector of claim 1 , wherein the light detector comprises a detector array configured to selectively detect illumination returned from the patterned structure.
3. The condensate detector of claim 2 , wherein the detector array is configured to detect illumination according to wavelength.
4. The condensate detector of claim 2 , wherein the detector array is configured to detect illumination that is offset from a reflected ray.
5. The condensate detector of claim 1 , wherein the roughened surface of the patterned structure comprises a plurality of surface features.
6. The condensate detector of claim 5 , wherein the plurality of surface features comprises at least one of holes and rods.
7. The condensate detector of claim 5 , wherein the surface features of the plurality of surface features are arranged periodically.
8. The condensate detector of claim 5 , wherein the surface features of the plurality of surface features are arranged randomly.
9. The condensate detector of claim 1 , further comprising a second illumination source configured to optically excite condensate on the patterned structure sufficiently to induce fluorescence in the condensate, when present, and a light detector configured to detect fluorescent spectra, the presence of condensate determinable from the detected fluorescent spectra.
10. The condensate detector of claim 1 , further comprising at least one window aligned between the roughened surface and each of the illumination source and the light detector, the at least one window isolating the illumination source and light detector from exposure to gaseous samples within the chamber, while allowing for efficient transmission of the illumination and the returned illumination therethrough.
11. The condensate detector of claim 10 , wherein the window comprises the patterned structure.
12. The condensate detector of claim 1 , further comprising a thermal source in thermal communication with the patterned structure, the thermal source operable to change a temperature of the roughened surface.
13. The condensate detector of claim 1 , wherein the gaseous chamber is sealable and reconfigurable to at least one of increase and decrease the interior volume, inducing a corresponding change in pressure of a sample gas contained therein.
14. The condensate detector of claim 1 , further comprising an outer layer disposed at least upon the roughened surface exposed to the gaseous sampling chamber, the outer layer operable to preferentially condense one of a water and a hydrocarbon.
15. The detector of claim 1 , wherein the condensate detector is configured to determine a quantity of a condensate on the roughened surface in response to returned illumination received at the light detector.
16. A method for detecting a condensate in a gaseous sample, the method comprising:
receiving the gaseous sample within a chamber defining an enclosed interior volume;
exposing a patterned structure forming a roughened surface to the gaseous sample, the patterned structure comprising an open volume accessible by the roughened surface, the open volume being at least about 10% of the interior volume of the chamber;
illuminating the patterned structure;
detecting at least a portion of the illumination returned from the patterned structure; and
determining from the detected illumination a presence of the condensate on the roughened surface.
17. The method of claim 16 , wherein illuminating the patterned structure comprises optically exciting condensate on the patterned structure sufficiently to induce fluorescence in a condensate, when present, the act of detecting the illumination comprising detecting fluorescent spectra, the presence of condensate determinable from the detected fluorescent spectra.
18. The method of claim 17 , further comprising determining from the detected illumination, a relative volume fraction dropout.
19. The method of claim 16 , wherein the act of detecting at least a portion of the illumination comprises detecting reflected illumination, the presence of condensate on the roughened surface determinable from the reflected illumination.
20. The method of claim 16 , wherein the act of detecting at least a portion of the illumination comprises detecting scattered illumination, the presence of condensate on the roughened surface determinable from the scattered illumination.
21. The method of claim 14 , wherein scattered illumination is detected offset from the reflected ray.
22. The method of claim 16 , further comprising varying at least one of a temperature and a pressure of the gaseous sample and repeating the acts of exposing, illuminating, detecting and determining a presence of the condensate.
23. The method of claim 22 , wherein the act of varying at least one of a temperature and a pressure comprises reducing a pressure, the pressure at which a presence of the condensate on the roughened surface is determined being indicative of a retrograde dew point.
24. The method of claim 16 , further comprising selectively evaporating the condensate from the roughened surface.
25. The method of claim 16 , further comprising selectively rejecting one of water and an oil from the opened surface of the roughened surface.
26. The method of claim 16 , wherein at least the act of determining a presence of the condensate is accomplished under the control of a processor executing a set of pre-programmed instructions.
27. An apparatus, comprising:
means for exposing a patterned structure forming a roughened surface to a gaseous sample, the means for exposing comprising an interior volume and the patterned structure comprising an open volume accessible by the roughened surface, the open volume being at least about 10% of the interior volume;
means for illuminating the patterned structure;
means for detecting at least a portion of the illumination returned from the patterned structure; and
means for determining from the detected illumination a presence of the condensate, at least one of reflectivity or scattering cross section of the patterned surface being indicative of condensate on the on the roughened surface.