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Digital in-line holography to quantify secondary droplets from the impact of a single drop on a thin film

Experiments in Fluids

Guildenbecher, Daniel R.; Engvall, Luke; Gao, Jian; Grasser, Thomas W.; Reu, Phillip L.; Chen, Jun

Digital in-line holography (DIH) is an optical technique which measures particle sizes and their three-dimensional (3D) positions and velocities. Here DIH and a recently proposed hybrid method of particle detection are applied to quantify the secondary droplets generated by the impact of a single drop on a thin film. By leveraging the expected symmetry between in-plane and out-of-plane velocities, experimental depth uncertainty is measured to be approximately 0.7 of the mean droplet diameter. Furthermore, comparison with previous measurements using alternative techniques shows good agreement with the measured temporal evolution of drop number, size, and velocity components. Finally, the power of DIH to extract the complex 3D morphology of the protruding jets is demonstrated. © 2014 Springer-Verlag Berlin Heidelberg.

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TYPE Journal Article YEAR 2014
ScopusOSTI

Developments in digital in-line holography enable validated measurement of 3D particle field dynamics

Guildenbecher, Daniel R.

Digital in-line holography is an optical technique which can be applied to measure the size, three-dimensional position, and three-component velocity of disperse particle fields. This work summarizes recent developments at Sandia National Laboratories focused on improvement in measurement accuracy, experimental validation, and applications to multiphase flows. New routines are presented which reduce the uncertainty in measured position along the optical axis to a fraction of the particle diameter. Furthermore, application to liquid atomization highlights the ability to measure complex, three-dimensional structures. Finally, investigation of particles traveling at near sonic conditions prove accuracy despite significant experimental noise due to shock-waves.

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TYPE SAND Report YEAR 2013
OSTIDOI

Digital holography simulations and experiments to quantify the accuracy of 3D particle location and 2D sizing using a proposed hybrid method

Applied Optics

Guildenbecher, Daniel R.; Reu, Phillip L.

The accuracy of digital in-line holography to detect particle position and size within a 3D domain is evaluated with particular focus placed on detection of nonspherical particles. Dimensionless models are proposed for simulation of holograms from single particles, and these models are used to evaluate the uncertainty of existing particle detection methods. From the lessons learned, a new hybrid method is proposed. This method features automatic determination of optimum thresholds, and simulations indicate improved accuracy compared to alternative methods. To validate this, experiments are performed using quasi-stationary, 3D particle fields with imposed translations. For the spherical particles considered in experiments, the proposed hybrid method resolves mean particle concentration and size to within 4% of the actual value, while the standard deviation of particle depth is less than two particle diameters. Initial experimental results for nonspherical particles reveal similar performance.

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TYPE Journal Article YEAR 2013
OSTIDOI
Results 151–175 of 182
Results 151–175 of 182