Measuring Vapour Cloud Concentrations with Digital Holography

Dehaeck, Sam; Colinet, Pierre

doi:10.1364/dh.2012.dtu2c.2

Cited by 4 publications

(3 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, up to now, these techniques have not been able to yield accurate enough measurements in the vicinity of the droplet as to compute the required normal gradients. In the past, interferometry has already been used to study the vapor cloud qualitatively. − In addition, quantitative results were already obtained by Toker and Stricker , for the global vapor mole fraction field around an evaporating droplet suspended from a millimetric wire. From the mole fraction obtained at the interface, they also deduced interfacial temperatures.…”

Section: Introductionmentioning

confidence: 99%

Vapor-Based Interferometric Measurement of Local Evaporation Rate and Interfacial Temperature of Evaporating Droplets

2014

Self Cite

View full text Add to dashboard Cite

A classical Mach-Zehnder interferometer is here used to measure the vapour cloud surrounding an evaporating pendant drop of 3M Novec HFE-7000 deposited on a silicon wafer with a syringe. However, in our rst experiments we observed that the droplet is highly mobile on such a perfectly at substrate, which rendered its tracking over time impossible. To make it 'stick' to a single location we use photo-litography to deposit a small object which remaines always within the droplet but still prevents the drop from moving away. This object has the shape of a disk 100 µm thick and 2 mm in diameter (noticeable in Figure S1a) made in SU-8 resin. We should stress that this protrusion has no impact on the validity of our vapour cloud measurements as it remains immersed in the drop for su ciently large drops (see Figure S1b). If it has any e ect, it will be on the recirculation inside the droplet, and even that is expected to be minor. Problems arise only for smaller drops, with a diameter approaching that of the cylindrical protrusion. As such, we decided to limit the present study to droplets larger than 2.4 mm in diameter. On the other hand, such a limitation to larger drops suited us well from the viewpoint of both a better resolution of the vapour cloud and a possible comparison with boundary-layer simulations (valid for large enough droplet sizes).

show abstract

Section: Introductionmentioning

confidence: 99%

Vapor-Based Interferometric Measurement of Local Evaporation Rate and Interfacial Temperature of Evaporating Droplets

2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…There are some methods reported and used by researchers for the conversion of refractive index and density fields to a concentration-temperature field, which are discussed next. Dehaeck et al [11] and Dehaeck and Colinet [12] measured the local evaporation rate and interfacial temperature based on digital holographic interferometry which gives a refractive index field. They assumed that the effect of temperature variation on refractive index is negligible and expressed the refractive index as a function of only the concentration.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of temperature and concentration fields from refractive index field for evaporation-induced convective flow

Sabnis,

Anand,

Bakshi

2023

Phys. Scr.

View full text Add to dashboard Cite

The present work relates to the simultaneous determination of concentration and temperature fields from a refractive index field, and is motivated by applications in evaporation. Several optical measurement techniques such as schlieren and interferometry can measure the refractive index field, which can then be converted to a density and temperature field for a single component system. The refractive index, however, is dependent on both temperature and concentration for a multi-component system involving combined heat and mass transfer. Hence, either the temperature or concentration field must be known to obtain the other. To circumvent this issue, several methods are evaluated in this study to extract concentration and temperature fields from a refractive index field. The evaluation is performed based on data from a coupled numerical solution of Navier-Stokes, energy and species conservation equations.The refractive index field can be obtained from this computed temperature and concentration field. This refractive index field is then separately used to obtain the combined temperature-concentration field using the method proposed in this work. This method is based on the premise that there is a relationship between temperature and concentration fields which can help to independently calculate both when the refractive index field is known. The temperature and concentration fields obtained using this approach are then compared with the originally computed field and the errors in them are estimated for a wide range of Lewis numbers. From the study, it is concluded that the proposed methods can be used to accurately determine the temperature and concentration fields from a given refractive index field.

show abstract

“…Previous work has already been on studying the vapor cloud in the vicinity of a droplet using interferometry, both qualitatively and quantitatively. − Dehaeck et al used a Mach–Zehnder interferometer to investigate pendant drops . Due to the small size of the droplet, the authors were bound to use a highly volatile liquid with a high refractive index of the vapor compared to the refractive index of pure ambient air.…”

Section: Introductionmentioning

confidence: 99%

Interferometric Imaging of Solvent Vapor of Evaporating Liquid Films

et al. 2021

View full text Add to dashboard Cite

The liquid deposition of thin films requires a thorough understanding of the underlying drying process, as it is an essential subprocess, where many defects may arise. To complement experimental studies, the present study uses a laser Michelson interferometer to visualize the vapor cloud of evaporating liquid films. The recorded interferometric patterns are evaluated using windowed Fourier filtering and a novel phase-unwrapping algorithm to allow for a robust analysis. Thin solvent stripes of different lengths are combined to yield a quantitative two-dimensional distribution of the solvent vapor concentration along a thin liquid stripe. The results show a considerable influence of natural convection during evaporation.

show abstract

Measuring Vapour Cloud Concentrations with Digital Holography

Abstract: In a Mach-Zehnder interferometer, the vapour cloud surrounding an evaporating droplet is imaged with digital holography. Using an Abel inversion, quantitative local evaporation rates can be measured precisely for the first time.

Cited by 4 publications

References 7 publications

Vapor-Based Interferometric Measurement of Local Evaporation Rate and Interfacial Temperature of Evaporating Droplets

Vapor-Based Interferometric Measurement of Local Evaporation Rate and Interfacial Temperature of Evaporating Droplets

Evaluation of temperature and concentration fields from refractive index field for evaporation-induced convective flow

Interferometric Imaging of Solvent Vapor of Evaporating Liquid Films

Contact Info

Product

Resources

About