An experimental and numerical study of the structure and stability of laminar opposed-jet flows

2010 ◽  
Vol 39 (1) ◽  
pp. 114-124 ◽  
Author(s):  
A. Ciani ◽  
W. Kreutner ◽  
C.E. Frouzakis ◽  
K. Lust ◽  
G. Coppola ◽  
...  
Keyword(s):  
Numerical Study ◽  
Jet Flows ◽  
Structure And Stability ◽  
Opposed Jet

Numerical study of particle behavior in laminar axisymmetric opposed-jet flows

2015 ◽  
Vol 270 ◽  
pp. 176-184 ◽  
Author(s):  
Dan Wu ◽  
Jing Li ◽  
Zhaohui Liu ◽  
Chuguang Zheng
Keyword(s):  
Numerical Study ◽  
Jet Flows ◽  
Particle Behavior ◽  
Opposed Jet

Investigation of the Flow Structures in Supersonic Free and Impinging Jet Flows

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
C. Chin ◽  
M. Li ◽  
C. Harkin ◽  
T. Rochwerger ◽  
L. Chan ◽  
...  
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Experimental Studies ◽  
Turbulence Models ◽  
Impinging Jet ◽  
Optical Methods ◽  
Navier Stokes ◽  
Jet Flows ◽  
Shock Cell ◽  
Rans Turbulence Models

A numerical study of compressible jet flows is carried out using Reynolds averaged Navier–Stokes (RANS) turbulence models such as k-ɛ and k-ω-SST. An experimental investigation is performed concurrently using high-speed optical methods such as Schlieren photography and shadowgraphy. Numerical and experimental studies are carried out for the compressible impinging at various impinging angles and nozzle-to-wall distances. The results from both investigations converge remarkably well and agree with experimental data from the open literature. From the flow visualizations of the velocity fields, the RANS simulations accurately model the shock structures within the core jet region. The first shock cell is found to be constraint due to the interaction with the bow-shock structure for nozzle-to-wall distance less than 1.5 nozzle diameter. The results from the current study show that the RANS models utilized are suitable to simulate compressible free jets and impinging jet flows with varying impinging angles.

CFD-DEM Simulations of Graphite Particle Collisions in Opposed Jet Mill

2020 ◽  
Author(s):  
Sifan Peng ◽  
Yujia Liu ◽  
Nan Gui ◽  
Xingtuan Yang ◽  
Jiyuan Tu ◽  
...  
Keyword(s):  
Supersonic Jet ◽  
Jet Flows ◽  
Acceleration Process ◽  
Collision Process ◽  
Particle Collisions ◽  
Preparation Methods ◽  
Graphite Particles ◽  
Dem Model ◽  
Opposed Jet ◽  
Compressible Gas

Abstract Graphite is widely used in nuclear reactors as moderator and structural material. Among present graphite preparation methods, air flow mill is considered to be qualified in the control of particle size and purity, and promising for future mass production. In this work, an opposed jet mill is designed to crush large graphite particles. The opposed jet mill accelerates the particles through two supersonic jet flows in opposite directions, and finally the particles collide in the crushing cavity. In order to estimate the performance of opposed jet mill, it is necessary to solve the coupling calculation of the compressible flow and the collision process of discrete particles. However, the research on calculating the compressible gas solid coupling problems is scarcely rare. In this paper, coupled CFD-DEM model is used to simulate the particle movement process with jet flows and accompanying jet in opposed jet mill. By comparing with experimental results, it is proved that these simulation results of the acceleration process of compressible gas through these nozzles and the collision process of the final two supersonic jet flows in the opposed-jet mill are accurate, with the accuracy model of the coupled CFD-DEM provided. The practice has proved that the contrastive flow mill has a broad application prospect in the production of graphite particles.

scholarly journals Numerical Study on Plane and Radial Wall Jets to Validate the 2D Assumption for an Idealized Downburst Outflow

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yongli Zhong ◽  
Zhitao Yan ◽  
Yan Li ◽  
Jie Luo ◽  
Hua Zhang
Keyword(s):  
Reynolds Number ◽  
Numerical Study ◽  
Critical Value ◽  
Plane Wall ◽  
Cloud Base ◽  
Jet Flows ◽  
Wall Jet ◽  
Wall Jets ◽  
Radial Wall ◽  
Velocity Decay

Turbulent radial and plane wall jets have been extensively investigated both experimentally and numerically over the past few decades. Previous studies mostly focused on the heat and mass transfers involved in jet flows. In this study, a comprehensive investigation was conducted on turbulent radial and plane wall jets, considering both jet spread and velocity decay for different parameters. The numerical results were compared with existing experimental measurements. The comparison focused on the velocity profile, jet spread, and velocity decay, and revealed that the Reynolds stress model (RSM) performs well in the simulation of both radial and plane wall jets. The results show that with a typical ratio of cloud base height to diameter for most downburst events, the effects of nozzle height and Reynolds number on the evolution of the radial wall jet are not significant. Both the jet spread and velocity decay exhibit a clear dependence on the Reynolds number below a critical value. Above this critical value, the plane wall jet becomes asymptotically independent of the Reynolds number. The co-flow was found to have a significant influence on the evolution of the plane wall jet. Comparatively, the jet spread and velocity of the radial wall jet were faster than those of the plane jet. For applications in civil engineering, it is valid to approximate the downburst outflow with a two-dimensional (2D) assumption from the perspective of longitudinal evolution of the flows.

Mixing in Turbulent Opposed Jet Flows

1995 ◽  
pp. 147-164
Author(s):  
E. Mastorakos ◽  
A. M. K. P. Taylor ◽  
J. H. Whitelaw
Keyword(s):  
Jet Flows ◽  
Opposed Jet

Numerical Study of Opposed-Jet H2/Air Diffusion Flame - Vortex Interactions

2000 ◽  
Vol 158 (1) ◽  
pp. 365-388 ◽  
Author(s):  
JERRY C. LEE ◽  
CHRISTOS E. FROUZAKIS ◽  
KONSTANTINOS BOULOUCHOS
Keyword(s):  
Diffusion Flame ◽  
Numerical Study ◽  
Vortex Interactions ◽  
Air Diffusion ◽  
Opposed Jet
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