Experiments in Fluids

, 55:1778 | Cite as

Microscale schlieren visualization of near-bubble mass transport during boiling of 2-propanol/water mixtures in a square capillary

  • Chen-li Sun
  • Chien-Yuan Huang
Research Article


In this study, we successfully utilize the microscale schlieren method to visualize the microscale mass transport near the vapor–liquid interface during boiling of 2-propanol/water mixtures in a square capillary. Because the variation in the refractive index with composition is much greater than that with temperature, the microscale schlieren method proves to be a powerful tool for investigating the solutocapillary convection without the interference of thermocapillarity. When the difference between the equilibrium vapor and liquid mole fractions is large, we observe high concentration gradients near the vapor–liquid interface due to both mass diffusion and the solutocapillary effects. Although the solutocapillary convection is decidedly affected by the eruptive nature of the boiling process, the near-bubble mass transport still plays a vital role in boiling heat transfer. In a square capillary of d = 900 μm, mass diffusion dominates and the depletion of 2-propanol near the vapor–liquid interface increases. This leads to an increase in the local bubble point causing the deterioration of heat transfer for 2-propanol/water mixtures. However, in the smaller square capillary of d = 500 μm, the solutocapillary effect becomes more important. The induced convection near the contact line helps to augment the boiling heat transfer at x = 0.015, despite the fact that mass diffusion tends to cause a higher concentration gradient normal to the bubble front during the boiling process. Herein, we prove that the microscale schlieren method is able to provide valuable insight into the leverage between different mechanisms in heat transfer during the vaporization process of 2-propanol/water mixtures in a square capillary.


Heat Transfer Coefficient Boiling Heat Transfer Marangoni Number Bubble Point Boiling Process 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols


Inner dimension of the square capillary


Mass diffusion coefficient


Heat transfer coefficient




Thermal conductivity


Radial distance between the interface and the center of the Marangoni vortex


Molar mass


Marangoni number


Refractive index


Input heat flux


Radius of curvature of the vapor–liquid interface








Molar volume




Cartesian coordinate along the capillary tube


Liquid mole fraction of 2-propanol in water


Cartesian coordinate perpendicular to the heating wall


Vapor mole fraction of 2-propanol in water


Cartesian coordinate opposite to the gravity direction



Azimuthal angle in the spherical coordinate






Surface tension





Bubble point


Dew point


Borosilicate glass


Vapor–liquid interface






Heated wall of the capillary


Stainless steel ANSI 304






More volatile component of the binary mixture, 2-propanol


Less volatile component of the binary mixture, water


Direction parallel to the vapor–liquid interface

Direction normal to the vapor–liquid interface



This work is supported by the Ministry of Science and Technology of Taiwan under Grant Number NSC 101-2221-E-002-064-MY3. The authors also wish to acknowledge and thank Tzu-hsun Hsiao for his assistance with the microscale schlieren setup.

Supplementary material

Supplementary material 1 (MP4 228 kb)

Supplementary material 2 (MP4 735 kb)

Supplementary material 3 (MP4 301 kb)


  1. Abbate G, Bernini U, Ragozzino E, Somma F (1978) The temperature dependence of the refractive index of water. J Phys D Appl Phys 11:1167–1172CrossRefGoogle Scholar
  2. Abe Y, Oka T, Mori YH, Nagashima A (1994) Pool boiling of a non-azeotropic binary mixture under microgravity. Int J Heat Mass Transf 37:2405–2413CrossRefGoogle Scholar
  3. Ahmed S, Carey VP (1998) Effects of gravity on the boiling of binary fluid mixtures. Int J Heat Mass Transf 41:2469–2483CrossRefGoogle Scholar
  4. Carey VP (2008) Liquid–vapor phase-change phenomena: an introduction to the thermophysics of vaporization and condensation processes in heat transfer equipment, 2nd edn. Taylor & Francis, New YorkGoogle Scholar
  5. Chan SH, Võ D, Nguyen TQ (2010) Sub-pixel motion estimation without interpolation. In: IEEE conference on acoustics, speech and signal processing. Dallas, TX, pp 722–725Google Scholar
  6. Choi B-D, Han J-W, Kim C-S, Ko S-J (2007) Motion-compensated frame interpolation using bilateral motion estimation and adaptive overlapped block motion compensation. IEEE Trans Circuits Syst Video Technol 17:407–416CrossRefGoogle Scholar
  7. Cooper MG, Lloyd AJP (1969) The microlayer in nucleate pool boiling. Int J Heat Mass Transf 12:895–913CrossRefGoogle Scholar
  8. Dhavaleswarapu HK, Chamarthy P, Garimella SV, Murthy JY (2007) Experimental investigation of steady buoyant-thermocapillary convection near an evaporating meniscus. Phys Fluids 19:082103CrossRefGoogle Scholar
  9. Fujita Y, Bai Q (1997) Critical heat flux of binary mixtures in pool boiling and its correlation in terms of Marangoni number. Int J Refrig 20:616–622Google Scholar
  10. Hargather MJ, Lawson MJ, Settles GS, Weinstein LM (2011) Seedless velocimetry measurements by schlieren image velocimetry. AIAA J 49:611–620CrossRefGoogle Scholar
  11. Hein M, Wieneke B, Seemann R (2013) Direct calculation of depth of correlation and weighting function in mPIV from experimental particle images. In: 10th international symposium on particle image velocimetry. Delft, NetherlandsGoogle Scholar
  12. Heitz D, Mémin E, Schnörr C (2010) Variational fluid flow measurements from image sequences: synopsis and perspectives. Exp Fluids 48:369–393CrossRefGoogle Scholar
  13. Heller W (1965) Remarks on refractive index mixture roles. J Phys Chem 69:1123–1129CrossRefGoogle Scholar
  14. Hildebrand FB (1992) Methods of applied mathematics, 2nd edn. Dover Publications, MineolazbMATHGoogle Scholar
  15. Irani M, Peleg S (1993) Improving resolution by image registration. CVGIP Graph Models Image Process 53:231–239Google Scholar
  16. Ishibashi E, Nishikawa K (1969) Saturated boiling heat transfer in narrow spaces. Int J Heat Mass Transf 12:863–894CrossRefGoogle Scholar
  17. Itoh K (1982) Analysis of the phase unwrapping algorithm. Appl Opt 21:2470CrossRefGoogle Scholar
  18. Knauer OS, Lang MC, Braeuer A, Leipertz A (2010) Simultaneous determination of the composition and temperature gradients in the vicinity of boiling bubbles in liquid binary mixtures using one-dimensional Raman measurements. J Raman Spectrosc 42:195–200CrossRefGoogle Scholar
  19. Liu C, Zeng A, Yuan X, Yu G (2008) Experimental study on mass transfer near gas-liquid interface through quantitative schlieren method. Chem Eng Res Des 86:201–207CrossRefGoogle Scholar
  20. McGillis WR, Carey VP (1996) On the role of Marangoni effects on the critical heat flux for pool boiling of binary mixtures. J Heat Transf 118:103–109CrossRefGoogle Scholar
  21. McGrew JL, Bamford FL, Rehm TR (1966) Marangoni flow: an additional mechanism in boiling heat transfer. Science 153:1106–1107CrossRefGoogle Scholar
  22. Merzkirch W (1974) Flow visualization. Academic Press, New YorkzbMATHGoogle Scholar
  23. Okhotsimskii A, Hozawa M (1998) Schlieren visualization of natural convection in binary gas-liquid systems. Chem Eng Sci 53:2547–2573CrossRefGoogle Scholar
  24. Olsen MG, Adrian RJ (2000) Out-of-focus effects on particle image visibility and correlation in microscopic particle image velocimetry. Exp Fluids 29:S166–S174CrossRefGoogle Scholar
  25. Passos JC, Possamai LFB, Hirata FR (2005) Confined and unconfined FC72 and FC87 boiling on a downward-facing disc. Appl Therm Eng 25:2543–2554CrossRefGoogle Scholar
  26. Poling BE, Prausnitz JM, O’Connell JP (2000) The properties of gases and liquids, 5th edn. McGraw-Hill, New YorkGoogle Scholar
  27. Raake D, Siekmann J (1989) Temperature and velocity fields due to surface tension driven flow. Exp Fluids 7:164–172CrossRefGoogle Scholar
  28. Savino R, di Francescantonio N, Fortezza R, Abe Y (2007) Heat pipes with binary mixtures and inverse Marangoni effects for microgravity applications. Acta Astronaut 61:16–26CrossRefGoogle Scholar
  29. Settles GS (2001) Schlieren and shadowgraph techniques, 2nd edn. Springer, New YorkCrossRefzbMATHGoogle Scholar
  30. Sha Y, Li Z, Wang Y, Huang J (2012) The Marangoni convection induced by acetone desorption from the falling soap film. Heat Mass Transf 48:749–755CrossRefGoogle Scholar
  31. Stephan K (1992) Heat transfer in condensation and boiling. Springer, BerlinCrossRefGoogle Scholar
  32. Stoica V, Stephan P (2007) Phase shift interferometry for accurate temperature measurement around a vapor bubble. Exp Heat Transf 20:261–275CrossRefGoogle Scholar
  33. Straub J (1995) The micro wedge model: A physical description of nucleate boiling without external forces. In: Proceedings of the 9th European symposium on gravity-dependent phenomena in physical sciences (Berlin, Germany)Google Scholar
  34. Sun C-l, Hsiao T-h (2013) Quantitative analysis of microfluidic mixing using microscale schlieren technique. Microfluid Nanofluid 15:253–265Google Scholar
  35. Tasić AŽ, Djordjević BD, Grozdanić DK, Radojković N (1992) Use of mixing rules in predicting refractive indices and specific refractivities for some binary liquid mixtures. J Chem Eng Data 37:310–313Google Scholar
  36. Taylor JR (1997) An introduction to error analysis, 2nd edn. University Science Books, SausalitoGoogle Scholar
  37. Thome JR, Marcinichen JB, Olivier JA (2012) Two-phase on-chip cooling systems for green data centers. In: Joshi Y, Kumar P (eds) Energy efficient thermal management of data centers. Springer, New YorkGoogle Scholar
  38. Utaka Y, Okuda S, Tasaki Y (2009) Configuration of the micro-layer and characteristics of heat transfer in a narrow gap mini/micro-channel boiling system. Int J Heat Mass Transf 52:2205–2214CrossRefGoogle Scholar
  39. Utaka Y, Kashiwabara Y, Ozaki M, Chen Z (2014) Heat transfer characteristics based on microlayer structure in nucleate pool boiling for water and ethanol. Int J Heat Mass Transf 68:479–488CrossRefGoogle Scholar
  40. van Stralen SJD (1968) The growth rate of vapour bubbles in superheated pure liquids and binary mixtures: part I: theory. Int J Heat Mass Transf 11:1467–1489CrossRefGoogle Scholar
  41. Wang Z, Lu P, Wang Y, Yang C, Mao Z-S (2013) Experimental investigation and numerical simulation of Marangoni effect induced by mass transfer during drop formation. AIChE J 59:4424–4439Google Scholar
  42. Ward CA, Duan F (2004) Turbulent transition of thermocapillary flow induced by water evaporation. Phys Rev E 69:056308CrossRefGoogle Scholar
  43. Wilson SK, Davis SH, Bankoff SG (1999) The unsteady expansion and contraction of a long two-dimensional vapour bubble between superheated or subcooled parallel plates. J Fluid Mech 391:1–27CrossRefzbMATHGoogle Scholar
  44. Wohlfarth C (2008) Landolt-Börnstein: numerical data and functional relationships in science and technology. In: Lechner MD (ed) Optical constants: refractive indices of pure liquids and binary liquid mixtures (Supplement to III/38), vol 47. Springer, BerlinGoogle Scholar
  45. Zhang Y, Utaka Y, Kashiwabara Y (2010) Formation mechanism and characteristics of a liquid microlayer in microchannel boiling system. J Heat Transf 132:122403CrossRefGoogle Scholar
  46. Zhao Y, Tsuruta T, Ji C (2003) Experimental study of nucleate boiling heat transfer enhancement in confined space. Exp Therm Fluid Sci 28:9–16CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringNational Taiwan UniversityTaipeiTaiwan

Personalised recommendations