Experimental and Computational Multiphase Flow 

About: Experimental and Computational Multiphase Flow is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Computer science & Medicine. It has an ISSN identifier of 2661-8869. Over the lifetime, 31 publications have been published receiving 76 citations. The journal is also known as: ECMF.

A review of recent study on the characteristics and applications of pebble flows in nuclear engineering

Abstract: This paper reviews the recent three-year progress on the investigations of pebble bed flows in nuclear engineering. Both the application of pebble beds in the fission reactors and the fusion reactors are included. The fundamental characteristics of packing, flows, conduction, convection, radiation, and the effective thermal conductivity of pebble beds are reviewed. The important issues on the design of the pebble beds as well as that related to the reactor safety are also introduced. In addition, the advances in measurement techniques and numerical coupled methods for exploring the pebble flow characteristics are categorized and summarized too.

Numerical study of the effect of nasopharynx airway obstruction on the transport and deposition of nanoparticles in nasal airways

Abstract: Although there is abundant literature for both experimental and numerical studies of respiratory aerosol exposure in nasal airways, research efforts concentrating on diseased nasal cavities undergoing pathological changes remain significantly less. This paper presents a comparative study of pre- and post-operative nasal airway models based on a 3-year-old nasal cavity model with severe nasopharynx obstruction due to the presence of adenoid hypertrophy. By numerically comparing the airflow dynamics and nanoparticle deposition characteristics in original diseased and post-operative healthy nasal airway models, our results demonstrated that nasopharynx obstruction can induce significantly biased flow distribution in the main nasal passage, despite the obstruction site is located downstream of the nasal airway. In addition, the regional particle deposition analysis revealed that the affected area can receive better nanoparticle aerosol delivery after receiving surgical treatment (adenoidectomy) due to restored normal flow fields. More importantly, ventilation and particle deposition improvements were achieved for the olfactory region in the post-operative nasal model, which indicates a more promising olfactory drug delivery using nanoparticles. Research findings are expected to provide scientific evidence for adenoidectomy planning and intranasal aerosol therapy, which can substantially improve present clinical treatment outcomes.

Study on bubble-induced turbulence in pipes and containers with Reynolds-stress models

Abstract: Abstract Bubbly flow still represents a challenge for large-scale numerical simulation. Among many others, the understanding and modelling of bubble-induced turbulence (BIT) are far from being satisfactory even though continuous efforts have been made. In particular, the buoyancy of the bubbles generally introduces turbulence anisotropy in the flow, which cannot be captured by the standard eddy viscosity models with specific source terms representing BIT. Recently, on the basis of bubble-resolving direct numerical simulation data, a new Reynolds-stress model considering BIT was developed by Ma et al. ( J Fluid Mech , 883: A9 (2020)) within the Euler—Euler framework. The objective of the present work is to assess this model and compare its performance with other standard Reynolds-stress models using a systematic test strategy. We select the experimental data in the BIT-dominated range and find that the new model leads to major improvements in the prediction of full Reynolds-stress components.

Analysis of occupants’ exposure risk of cough-expelled droplets in the workspace with various mixing ventilation layouts

Abstract: This study numerically investigated the transport characteristics of the cough-expelled droplets and their corresponding exposure risk of each occupant under various mixing ventilation layouts. Transient simulations were conducted in a conference room, while pathogen-bearing droplets were released by a standing speaker. The results showed that droplet residues (< 40 μm) had a high potential to reach occupant’s breathing zone, among which the number fraction of aerosol residues (< 10 μm) could be nearly doubled compared with that of the rest droplet residues in the breathing zone. Occupants’ exposure risks were found very sensitive to the ventilation layouts. The strong ventilated flow could significantly promote droplet dispersions when those inlets were closely located to the infectious speaker, resulting in all occupants exposed to a considerable fraction of aerosols and droplets within a given exposure time of 300 s. The mixing ventilation layout did not have a consistent performance on restricting the pathogen spread and controlling the occupant’s exposure risk in an enclosed workspace. Its performance could be highly sensitive to the location of the infectious agent. Centralized vent layouts could provide relatively more consistent performance on removing droplets, whilst some local airflow recirculation with locked droplets were noticed.