scholarly journals A 2-D DNS study of the effects of nozzle geometry, ignition kernel placement and initial turbulence on prechamber ignition

2021 ◽  
Vol 225 ◽  
pp. 272-290
Author(s):  
Sotirios Benekos ◽  
Christos E. Frouzakis ◽  
George K. Giannakopoulos ◽  
Christos Altantzis ◽  
Konstantinos Boulouchos
Keyword(s):  
Nozzle Geometry ◽  
Ignition Kernel ◽  
Initial Turbulence

Influence of Torch Nozzle Geometry on Plasma Jet Properties

1997 ◽  
Vol 7 (6) ◽  
pp. 1361-1375 ◽  
Author(s):  
O. H. Chang ◽  
A. Kaminska ◽  
M. Dudeck
Keyword(s):  
Plasma Jet ◽  
Nozzle Geometry

scholarly journals Sensitivity analysis of FDA´s benchmark nozzle regarding in vitro imperfections - Do we need asymmetric CFD benchmarks?

2020 ◽  
Vol 6 (3) ◽  
pp. 78-81
Author(s):  
Michael Stiehm ◽  
Christoph Brandt-Wunderlich ◽  
Stefan Siewert ◽  
Klaus-Peter Schmitz ◽  
Niels Grabow ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
In Silico ◽  
Nozzle Geometry ◽  
Geometrical Imperfection ◽  
Custom Made ◽  
Inlet Conditions ◽  
Silicone Model ◽  
Bench Testing

AbstractModern technologies and methods such as computer simulation, so-called in silico methods, foster the development of medical devices. For accelerating the uptake of computer simulations and to increase credibility and reliability the U.S. Food and Drug Administration organized an inter-laboratory round robin study of a generic nozzle geometry. In preparation of own bench testing experiment using Particle Image Velocimetry, a custom made silicone nozzle was manufactured. By using in silico computational fluid dynamics method the influence of in vitro imperfections, such as inflow variations and geometrical deviations, on the flow field were evaluated. Based on literature the throat Reynolds number was varied Rethroat = 500 ± 50. It could be shown that the flow field errors resulted from variations of inlet conditions can be largely eliminated by normalizing if the Reynolds number is known. Furthermore, a symmetric imperfection of the silicone model within manufacturing tolerance does not affect the flow as much as an asymmetric failure such as an unintended curvature of the nozzle. In brief, we can conclude that geometrical imperfection of the reference experiment should be considered accordingly to in silico modelling. The question arises, if an asymmetric benchmark for biofluid analysis needs to be established. An eccentric nozzle benchmark could be a suitable case and will be further investigated.

scholarly journals GMAW Shielding Gas Flow Optimisation by Refinement of Nozzle Geometry

PRICM ◽  
2013 ◽  
pp. 2131-2137
Author(s):  
S.W. Campbell ◽  
A.M. Galloway ◽  
N.A. McPherson
Keyword(s):  
Gas Flow ◽  
Nozzle Geometry ◽  
Shielding Gas

Research on Nozzle Geometry Measurement with Synchrotron Radiation X-Ray Phase Contrast Imaging Technique

2013 ◽  
Vol 779-780 ◽  
pp. 1007-1014
Author(s):  
Cang Su Xu ◽  
Qi Yuan Luo ◽  
Jian Ma ◽  
Fang Qi ◽  
Yi Fan Xu
Keyword(s):  
Internal Structure ◽  
Light Source ◽  
Flow Dynamics ◽  
Nozzle Geometry ◽  
Contrast Imaging ◽  
X Ray ◽  
Performance And Emission ◽  
Injector Nozzle ◽  
Fuel Atomization ◽  
Geometry Measurement

The performance and emission characteristics of diesel engines are largely governed by fuel atomization and spray processes which in turn are strongly influenced by the flow dynamics inside the injector nozzle. Accurate measurement of the nozzle geometry is important for the study of the flow dynamics. Using the third-generation synchrontron radiation light source of the ShangHai Light Source (SSRF), the research team successfully captured the internal structure images of the single hole nozzle and multi-hole nozzle. According to the captured images, the researchers clearly observed the internal structure of nozzle as well as the sac region. The diameter and length of the nozzles and orifice angle were also be accurately measured.

Behavior of Radial Incompressible Flow in Pneumatic Dimensional Control Systems

2003 ◽  
Vol 125 (5) ◽  
pp. 843-850 ◽  
Author(s):  
G. Roy ◽  
D. Vo-Ngoc ◽  
D. N. Nguyen ◽  
P. Florent
Keyword(s):  
Gas Flow ◽  
Flow Behavior ◽  
Pressure Gauge ◽  
Axisymmetric Flow ◽  
Low Pressure ◽  
Industrial Applications ◽  
Nozzle Geometry ◽  
Machined Surface ◽  
Flow Area ◽  
Simpler Algorithm

The application of pneumatic metrology to control dimensional accuracy on machined parts is based on the measurement of gas flow resistance through a restricted section formed by a jet orifice placed at a small distance away from a machined surface. The backpressure, which is sensed and indicated by a pressure gauge, is calibrated to measure dimensional variations. It has been found that in some typical industrial applications, the nozzles are subject to fouling, e.g., dirt and oil deposits accumulate on their frontal areas, thus requiring more frequent calibration of the apparatus for reliable service. In this paper, a numerical and experimental analysis of the flow behavior in the region between an injection nozzle and a flat surface is presented. The analysis is based on the steady-state axisymmetric flow of an incompressible fluid. The governing equations, coupled with the appropriate boundary conditions, are solved using the SIMPLER algorithm. Results have shown that for the standard nozzle geometry used in industrial applications, an annular low-pressure separated flow area was found to exist near the frontal surface of the nozzle. The existence of this area is believed to be the cause of the nozzle fouling problem. A study of various alternate nozzle geometries has shown that this low-pressure recirculation area can be eliminated quite readily. Well-designed chamfered, rounded, and reduced frontal area nozzles have all reduced or eliminated the separated recirculation flow area. It has been noted, however, that rounded nozzles may adversely cause a reduction in apparatus sensitivity.

Effects of Gun Nozzle Geometry on High Velocity Oxygen-Fuel (HVOF) Thermal Spraying Process

1998 ◽  
Author(s):  
K. Sakaki ◽  
Y. Shimizu ◽  
Y. Gouda ◽  
A. Devasenapathi
Keyword(s):  
Numerical Simulation ◽  
Experimental Studies ◽  
Thermal Spraying ◽  
Deposition Efficiency ◽  
Divergence Angle ◽  
Nozzle Geometry ◽  
Oxide Content ◽  
Hvof Thermal Spraying ◽  
Throat Diameter ◽  
Spraying Process

Abstract Effect of nozzle geometry (such as throat diameter of a barrel nozzle, exit diameter and exit divergence angle of a divergent nozzle) on HVOF thermal spraying process (thermodynamical behavior of combustion gas and spray particles) was investigated by numerical simulation and experiments with Jet KoteTM II system. The process changes inside the nozzle as obtained by numerical simulation studies were related to the coating properties. A NiCrAIY alloy powder was used for the experimental studies. While the throat diameter of the barrel nozzle was found to have only a slight effect on the microstructure, hardness, oxygen content and deposition efficiency of the coatings, the change in divergent section length (rather than exit diameter and exit divergence angle) had a significant effect. With increase in divergent section length of the nozzle, the amount of oxide content of the NiCrAIY coatings decreased and the deposition efficiency increased significantly. Also, with increase in the exit diameter of the divergent nozzle, the gas temperature and the degree of melting of the particle decreased. On the other hand the calculated particle velocity showed a slight increase while the gas velocity increased significantly.

Sign in / Sign up

Export Citation Format

Share Document