Simultaneous measurement of monocomponent droplet temperature/refractive index, size and evaporation rate with phase rainbow refractometry

Wu, Yingchun; Crua, Cyril; Li, Haipeng; Saengkaew, Sawitree; Mädler, Lutz; Wu, Xuecheng; Gréhan, Gérard

doi:10.1016/j.jqsrt.2018.04.034

Cited by 26 publications

(10 citation statements)

References 64 publications

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“…New models are to be developed to achieve high accuracy and fast computation, and one possible approach is to extend the complex angular momentum theory to high refractive index particles. With regard to phase rainbow refractometry for droplet evaporation/condensation measurement [16,17], the phases of the refraction ripples in primary rainbow and classical reflection ripple structures vary with droplet diameter, and thus two phase shifts will exist. Moreover, the two ripples interfere and overlap, making the phase of the real superimposed ripples present a more complicated behavior.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, the two ripples interfere and overlap, making the phase of the real superimposed ripples present a more complicated behavior. The relationship in [16,17] only describes the reflection ripples while a new relationship is to be derived for the refraction ripples. As for global rainbow technique, its signal summarizes hundreds and even thousands of polydisperse particles, and smooths both reflection and refraction ripples since both are high frequency, low amplitude and random phase, yielding a smooth Airy rainbow as in previous studies [13,32].…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, the rainbow phenomenon has been utilized to develop powerful techniques for the experimental diagnostic of droplets and sprays. Since probably the first demonstration of standard rainbow refractometry for droplet refractive index measurement [12], the global rainbow technique [13], one-dimensional rainbow refractometry [14,15], phase rainbow refractometry [16,17] and multi-wavelength rainbow imaging [18,19] have been sequentially proposed. Rainbow refractometry has been applied to characterize a wide range of droplets, including water [20,21,22,23], alkanes [24,25,26,27,28,29,30], kerosene [31], ethanol [32,14], monoethanolamine [33,34], diethyl ether [35] and suspensions [36,37], and flow jets [38,39] or optical fibers [40] as well.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Primary rainbow of high refractive index particle (1.547<n<2) has refraction ripples

Crua

et al. 2018

Optics Communications

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Primary rainbow (Debye series, p=2) of a common liquid droplet, i.e., water drop, has a smooth Airy rainbow structure, and the superimposed high frequency ripple structures are mostly generated by interference of refraction (p=2) and reflection (p=0). In this work, the primary rainbow (p=2) of a particle with high refractive index (1.547< n <2) is found to have ripples. This is because the primary rainbow transits from 2-rays rainbow to 3-rays rainbow. A third refraction light with higher incident angle emerges at the same angle of the classical Airy rainbow, and its interference with the refractions around Descartes ray gives birth to the high frequency ripples. Characteristics of this refraction ripples, i.e., angular frequency, are investigated, and implications of this special ripple for particle measurement are also pointed out. This refraction ripple is not observed in other higher order rainbows.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Primary rainbow of high refractive index particle (1.547<n<2) has refraction ripples

Crua

et al. 2018

Optics Communications

Self Cite

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“…In addition, the phase of the primary rainbow is also sensitive to changes in droplet size and RI. When information is deducted from the phase of the primary rainbow, the technique is named phase rainbow refractometry and has been used by Wu et al to measure the temperature, size, and evaporation rate of fuel droplets simultaneously [ 92 , 93 ]. They were able to detect nanoscale size changes in a direct way, rather than by tracking diameter changes in time.…”

Section: Physics Of Particle Formation From a Drying Dropletmentioning

confidence: 99%

Unraveling Particle Formation: From Single Droplet Drying to Spray Drying and Electrospraying

et al. 2020

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Spray drying and electrospraying are well-established drying processes that already have proven their value in the pharmaceutical field. However, there is currently still a lack of knowledge on the fundamentals of the particle formation process, thereby hampering fast and cost-effective particle engineering. To get a better understanding of how functional particles are formed with respect to process and formulation parameters, it is indispensable to offer a comprehensive overview of critical aspects of the droplet drying and particle formation process. This review therefore closely relates single droplet drying to pharmaceutical applications. Although excellent reviews exist of the different aspects, there is, to the best of our knowledge, no single review that describes all steps that one should consider when trying to engineer a certain type of particle morphology. The findings presented in this article have strengthened the predictive value of single droplet drying for pharmaceutical drying applications like spray drying and electrospraying. Continuous follow-up of the particle formation process in single droplet drying experiments hence allows optimization of manufacturing processes and particle engineering approaches and acceleration of process development.

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“…Among them, rainbow refractometry has drawn great attention since it is a truly non-intrusive temperature measurement method without any addition of fluorescence product. Without being exhaustive listed, some of the significant contributions have been made by the group of Wu [6], Saengkaew et al [7], and Promvongsa et al [8]. This technique has a wide range of application configurations, such as single droplets, mono-dispersed droplets as well as spray droplets [9].…”

Section: Introductionmentioning

confidence: 99%

Measurement of droplets size and temperature under different conditions by using rainbow technique

Hespel

Foucher

et al. 2021

ICLASS

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The precise measurement of particle size and temperature during the droplet evaporation process is critical yet remains challenging. A non-intrusive method named the rainbow technique is utilized to investigate the evaporation process of ethanol droplets. By analyzing the rainbow patterns captured in the vicinity of the rainbow angle, the average temperature and size of droplet can be simultaneously extracted. Then, the evaporation process of ethanol droplet stream is conducted under ambient temperatures of 293 K to 313 K. The results validate the accuracy of the rainbow technique in measuring the droplet size and refractive index. Furthermore, a higher ambient temperature and a smaller droplet induce a larger reduction rate in droplet diameter. Moreover, the experimental results are quantitatively compared with the simulation data. Both the numerical and experimental results exhibit a reduction tendency of temperature, revealing the cooling effect as a result of vaporization. Besides, it indicates that the measured temperature by the rainbow technique is the equivalent temperature in the liquid phase.

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Simultaneous measurement of monocomponent droplet temperature/refractive index, size and evaporation rate with phase rainbow refractometry

Cited by 26 publications

References 64 publications

Primary rainbow of high refractive index particle (1.547<n<2) has refraction ripples

Primary rainbow of high refractive index particle (1.547<n<2) has refraction ripples

Unraveling Particle Formation: From Single Droplet Drying to Spray Drying and Electrospraying

Measurement of droplets size and temperature under different conditions by using rainbow technique

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