This work presents a noncontact laser-based thermoreflectance technique to measure changes in temperature or concentration at a liquid surface. Changes in temperature and, for multi-component liquid mixtures, concentration result in a change in the liquid index of refraction, which alters the reflectivity of the liquid surface. An intensity-stabilized diode laser and silicon photodiode are used to monitor the surface reflectivity. Temperature variations in 1-propanol, methanol, ethanol, and water are measured with uncertainties of 0.5, 0.7, 0.7, and 3.7°C, respectively. For binary mixtures, the concentration of a methanol-propanol mixture is measured with an uncertainty of 0.3 percent. The experimental configuration is noninvasive, simple in design, and inexpensive. The technique can be used over a wide range of time scales, ranging from micro-seconds to minutes, and can achieve high spatial resolution by focusing the probe laser beam to a small spot size on the liquid surface. [S0022-1481(00)02803-6]

Issue Section:
Microscale Heat Transfer
Keywords:
thermoreflectance, liquid mixtures, spectral methods of temperature measurement, spectrochemical analysis, measurement by laser beam, Heat Transfer, Laser, Liquid, Measurement Techniques, Temperature and Concentration
Topics:
Lasers, Temperature, Temperature measurement, Water, Methanol, Ethanol
1.
Qiu
,
T. Q.
,
Grigoropoulos
,
C. P.
, and
Tien
,
C. L.
,
1993
, “
Novel Technique for Noncontact and Microscale Temperature Measurements
,”
Exp. Heat Transfer
,
6
, pp.
231
–
241
.
2.
Chen
,
S.
, and
Grigoropoulos
,
C. P.
,
1997
, “
Noncontact Nanosecond-Time-Resolution Temperature Measurement in Excimer Laser Heating of Ni-P Disk Substrates
,”
Appl. Phys. Lett.
,
71
, pp.
3191
–
3193
.
3.
Lee, A. S., Hostetler, J. L., and Norris, P. M., 1996, “Temperature Measurement by Thermoreflectance at Near Grazing Angles,” Proceedings of the 1996 ASME International Mechanical Engineering Congress and Exposition, Vol. 59, , Atlanta, GA, Nov. 17–22, ASME, New York, pp. 77–82.
4.
Lee
,
A. S.
, and
Norris
,
P. M.
,
1997
, “
A New Optical Method for Measuring Surface Temperature at Large Incident Probe Angles
,”
Rev. Sci. Instrum.
,
68
, pp.
1307
–
1311
.
5.
Longtin, J. P., and Fan, C. H., 1998, “Laser-Based Temperature Measurement at a Liquid Surface,” Proceedings, 11th International Heat Transfer Conference, Vol. 4, Kyongju, Korea, Taylor and Francis, London, pp. 119–123.
6.
Bergman
,
T. L.
,
Incropera
,
F. P.
, and
Stevenson
,
W. H.
,
1985
, “
Miniature Fiber-Optic Refractometer for Measurement of Salinity in Double-Diffusive Thermohaline Systems
,”
Rev. Sci. Instrum.
,
56
, pp.
291
–
296
.
7.
Bergman
,
T. L.
,
Munoz
,
D. R.
,
Incropera
,
F. P.
, and
Viskanta
,
R.
,
1986
, “
Measurement of Salinity Distributions in Salt-Stratified, Double-Diffusive Systems by Optical Deflectometry
,”
Rev. Sci. Instrum.
,
57
, pp.
2538
–
2542
.
8.
Longtin
,
J. P.
, and
Fan
,
C. H.
,
1998
, “
Precision Laser-Based Concentration and Refractive Index Measurement of Liquids
,”
Microscale Thermophys. Eng.
,
2
, pp.
261
–
272
.
9.
Graeme, J., 1996, Photodiode Amplifiers—Op Amp Solutions, McGraw-Hill, New York.
10.
Jenkins, F. A., and White, H. E., 1976, Fundamentals of Optics, 4th Ed., McGraw-Hill, New York.
11.
Solimini
,
D.
,
1966
, “
Loss Measurements of Organic Materials at 6328 Å
,”
J. Appl. Phys.
,
37
, pp.
3314
–
3315
.
12.
Stone
,
J.
,
1972
, “
Measurements of the Absorption of Light in Low-Loss Liquids
,”
J. Opt. Soc. Am.
,
62
, pp.
327
–
333
.
13.
Lusty
,
M. E.
, and
Dunn
,
M. H.
,
1987
, “
Refractive Indices and Thermo-Optical Properties of Dye Laser Solvents
,”
Appl. Phys. B: Photophys. Laser Chem.
,
44
, pp.
193
–
198
.
14.
Fan, C. H., 1998, “Laser-Based Measurement of Liquid Refractive Index, Concentration, and Temperature,” Master thesis, State University of New York, Stony Brook, NY, pp. 29–30.
15.
Sun, J., Longtin, J. P., and Irvine, Jr., T. F., 2000, “Laser-Based Thermal Pulse Measurement of Liquid Thermophysical Properties,” Int. J. Heat Mass Transf., to be published.
16.
Beaton, C. F., and Hewitt, G. F., 1988, Physical Property Data for the Design Engineering, Hemisphere, New York.
17.
Dean, J. A., 1973, Lange’s Handbook of Chemistry, 11th Ed., J. A. Dean, ed., McGraw-Hill, New York.
18.
Lide, D. R., 1998, CRC Handbook of Chemistry and Physics, D. R. Lide, ed., CRC Press, Boca Raton, FL.
19.
Longtin
,
J. P.
,
Hijikata
,
K.
, and
Ogawa
,
K.
,
1999
, “
Laser-Induced Surface-Tension-Driven Flows in Liquid
,”
Int. J. Heat Mass Transf.
,
42
, pp.
85
–
93
.
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