Time-resolved PIV measurements in a low-aspect ratio facility of randomly packed spheres and flow analysis using modal decomposition

Nguyen, Thien; Kappes, Ethan; King, Stephen; Hassan, Yassin A.; Ugaz, Victor M.

doi:10.1007/s00348-018-2583-3

Cited by 36 publications

(10 citation statements)

References 69 publications

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“…A more recent study was aimed at simulating the flow in a random pebble bed. 37 This random pebble-bed geometry was obtained from an experiment conducted by Nguyen et al 38 The experiment measured detailed velocity distributions using particle image velocimetry (PIV) and matched index of refraction within a pebble bed. A DNS of the flow field was then conducted for a short section of the bed comprising 147 pebbles, corresponding to the test section and additional layers of pebbles.…”

Section: Iiia3 Pebble Bedsmentioning

confidence: 99%

Cardinal: A Lower-Length-Scale Multiphysics Simulator for Pebble-Bed Reactors

et al. 2021

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This paper demonstrates a multiphysics solver for pebble-bed reactors, in particular, for Berkeley's pebble-bed -fluoride-salt-cooled high-temperature reactor (PB-FHR) (Mark I design). The FHR is a class of advanced nuclear reactors that combines the robust coated particle fuel form from high-temperature gas-cooled reactors, the direct reactor auxiliary cooling system passive decay removal of liquid-metal fast reactors, and the transparent, high-volumetric heat capacitance liquid-fluoride salt working fluids (e.g., FLiBe) from molten salt reactors. This fuel and coolant combination enables FHRs to operate in a high-temperature, low-pressure design space that has beneficial safety and economic implications. The PB-FHR relies on a pebblebed approach, and pebble-bed reactors are, in a sense, the poster child for multiscale analysis.Relying heavily on the MultiApp capability of the Multiphysics Object-Oriented Simulation Environment (MOOSE), we have developed Cardinal, a new platform for lower-length-scale simulation of pebble-bed cores. The lower-length-scale simulator comprises three physics: neutronics (OpenMC), thermal fluids (Nek5000/ NekRS), and fuel performance (BISON). Cardinal tightly couples all three physics and leverages advances in MOOSE, such as the MultiApp system and the concept of MOOSE-wrapped applications. Moreover, Cardinal can utilize graphics processing units for accelerating solutions. In this paper, we discuss the development of Cardinal and the verification and validation and demonstration simulations.

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Section: Iiia3 Pebble Bedsmentioning

confidence: 99%

Cardinal: A Lower-Length-Scale Multiphysics Simulator for Pebble-Bed Reactors

et al. 2021

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“…For each flow measurement of the tested materials, the camera operated in a single-frame mode and captured a sequence of 8341 images of 1280 × 1280 pixels at a frequency of 500 Hz. The collection of PIV experimental images was processed using in-house codes ( Eckstein and Vlachos, 2009 , Nguyen et al, 2017 , Nguyen and Hassan, 2017 , Nguyen et al, 2018a , Nguyen et al, 2018b , Nguyen et al, 2019a , Nguyen et al, 2019b , Nguyen et al, 2019c , Nguyen et al, 2020 ). The estimated overall uncertainty of the PIV processing code was approximately 0.1 pixels, yielding less than 1% of the mean centerline velocity of the upstream region.…”

Section: Materials Experimental Facility and Measurement Techniquesmentioning

confidence: 99%

A fluid mechanics explanation of the effectiveness of common materials for respiratory masks

Maher¹,

Chavez²,

Tomaz³

et al. 2020

International Journal of Infectious Diseases

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Highlights Filtration efficiency of common materials for respiratory masks are investigated. Effects of materials to the upstream-downstream fluid flow regions are measured. One-layer masks have similar efficiency; multilayer masks' efficiency is greater than 90%. Comfortable-effective masks can be made from multilayer cotton and non-woven fabric. Washing masks reduces effectiveness; masks should be used a limited number of times.

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“…A more recent study was aimed at simulating the flow in a random pebble bed [7]. This random pebble bed geometry was obtained from an experiment conducted by Nguyen et al [8]. However, only a small section of the whole domain from the experiment was studied.…”

Section: Verification and Validationmentioning

confidence: 99%