Digital in-line holography in a droplet with cavitation air bubbles

Abstract

In this publication, the modelisation of an air bubble as inclusion in a droplet is treated from scalar theory point of view (Fresnel's theory). The elaborated model is compared with Lorenz-Mie scattering theory and with an experimental results. Circle polynomials and scaled pupil function are the background of this work to take into account the critical angle effect that arises at a transition from a higher index to a lower index medium.

Numerical Models for Exact Description of in-situ Digital In-Line Holography Experiments with Irregularly-Shaped Arbitrarily-Located Particles

“…The possibility to simulate this experiment is particularly attractive for us. This set-up can indeed be used to detect 50 nm nanoparticles [22]: the droplet is seeded with nanoparticles. The droplet is then heated using a second laser (a frequency-doubled Nd:YAG laser emitting 4 ns, 10 mJ pulses in our case).…”

“…The droplet is then heated using a second laser (a frequency-doubled Nd:YAG laser emitting 4 ns, 10 mJ pulses in our case). Heating a nanoparticle creates a bubble which is reconstructed using Digital In-Line Holography [22]. For more details concerning the description of spherical micro-bubbles in this experiment, please refer to [22].…”

“…Heating a nanoparticle creates a bubble which is reconstructed using Digital In-Line Holography [22]. For more details concerning the description of spherical micro-bubbles in this experiment, please refer to [22]. This indirect detection method is particularly efficient.…”

“…Depending on the application (visualization of bubbles in a cavitation tunnel, visualization of droplets through a transparent engine), the set-up has to be carefully designed. In order to optimize the design, we have developed analytical models that calculate theoretically in-line holograms generated by various kinds of spherical opaque or transparent particles [19,[21][22][23][24]. Our analytical models allow to determine precisely reconstruction parameters from parameters of the set-up, through estimation of the coefficients of its optical transfer matrix.…”

Digital holographic sizer for coal powder size distribution measurement: preliminary simulation and experiment

“…Digital holography (DH) is a real 3D imaging technique [14], and capable of measuring size, 3D position, velocimetry or even 3D morphology of particles [15][16][17][18][19][20][21][22][23]. As a powerful tool for particle fields diagnostics, the DH method has been applied to measure sprayed droplets [24,25], moving bubbles [26,27], pulverized coal flame [28,29] and solid particles in gas-solid two-phase flows [30]. The utilization of the DH method based on intensity reconstruction is hardly affected by the physical property such as refractive index other than the shape of the object.…”