Flow Field Simulation of the Nozzle and the Influence of Size

2013 ◽  
Vol 437 ◽  
pp. 47-50 ◽  
Author(s):  
Shi Nian Liu ◽  
Wei Su ◽  
Zeng Fu Wei
Keyword(s):  
Shock Wave ◽  
Flow Field ◽  
Jet Flow ◽  
Cleaning Efficiency ◽  
Free Jet ◽  
Transmission Distance ◽  
Supersonic Underexpanded Jet ◽  
The Stability ◽  
Dry Ice Blasting ◽  
Free Jet Flow

The nozzle is one of the critical parts in the dry-ice blasting system, spray nozzle's structure and the air supersonic free jet flow field take big influence on cleaning efficiency during the blasting process. Inner flow field of different size nozzles and the flow field of jet flow sprayed by nozzles were simulated with software Fluent, which obtained the distribution results of pressure and velocity of fluid. The result indicated that the supersonic underexpanded jet take place in the nozzle outlet and the shock wave is gained as the pressure at the nozzle exit is greater than the atmospheric pressure. With increasing of the nozzle size, the velocity decrease of airflow become slower, the shock wave transmission distance increase and deduce the stability of the jet flow.

Dusty Gas Flow in a Converging-Diverging Nozzle

1999 ◽  
Vol 121 (4) ◽  
pp. 908-913 ◽  
Author(s):  
O. Igra ◽  
I. Elperin ◽  
G. Ben-Dor
Keyword(s):  
Steady State ◽  
Flow Field ◽  
Gas Flow ◽  
Jet Flow ◽  
Mach Disk ◽  
Solid Particles ◽  
Steady State Flow ◽  
Free Jet ◽  
State Flow ◽  
Free Jet Flow

The flow in a converging-diverging nozzle is studied numerically. The flowing medium is a suspension composed of gas seeded with small, spherical, solid particles. The solution covers the entire flow history, from its initiation and until a steady state flow is reached. The covered flow domain includes both the flow field inside the nozzle and part of the free jet flow outside of the nozzle exit plane. The solution is repeated for different solid particle diameters, ranging from 0.5 μm to 50 μm, and different dust loading ratios. It is shown that the presence of solid particles in the flow has a significant effect on the developed flow field, inside and outside the nozzle. In particular, by a proper choice of particles diameter lateral pressure waves and the secondary shock wave can be significantly attenuated. The solid particles size has also a marked effect on the position and size of the Mach disk appearing in the free jet flow. It is also shown that in a suspension case a steady state flow is reached faster than in a similar pure gas flow.

A free jet flow reactor for ion/molecule reaction studies at very low energies

1990 ◽  
Vol 97 (1) ◽  
pp. 55-86 ◽  
Author(s):  
M. Hawley ◽  
T.L. Mazely ◽  
L.K. Randeniya ◽  
R.S. Smith ◽  
X.K. Zeng ◽  
...  
Keyword(s):  
Flow Reactor ◽  
Jet Flow ◽  
Free Jet ◽  
Molecule Reaction ◽  
Low Energies ◽  
Free Jet Flow

PREDICTION OF NOISE GENERATED BY A ROUND NOZZLE JET FLOW USING COMPUTATIONAL AEROACOUSTICS

2011 ◽  
Vol 19 (03) ◽  
pp. 291-316 ◽  
Author(s):  
ALI UZUN ◽  
M. YOUSUFF HUSSAINI
Keyword(s):  
Flow Field ◽  
Near Field ◽  
Internal Flow ◽  
Jet Flow ◽  
Computational Aeroacoustics ◽  
Far Field ◽  
Free Jet ◽  
Grid Points ◽  
Field Noise ◽  
Inflow Conditions

This paper demonstrates an application of computational aeroacoustics to the prediction of noise generated by a round nozzle jet flow. In this study, the nozzle internal flow and the free jet flow outside are computed simultaneously by a high-order accurate, multi-block, large-eddy simulation (LES) code with overset grid capability. To simulate the jet flow field and its radiated noise, we solve the governing equations on approximately 370 million grid points using high-fidelity numerical schemes developed for computational aeroacoustics. Projection of the near-field noise to the far-field is accomplished by coupling the LES data with the Ffowcs Williams–Hawkings method. The main emphasis of these simulations is to compute the jet flow in sufficient detail to accurately capture the physical processes that lead to noise generation. Two separate simulations are performed using turbulent and laminar inflow conditions at the jet nozzle inlet. Simulation results are compared with the corresponding experimental measurements. Results show that nozzle inflow conditions have an influence on the jet flow field and far-field noise.

1012 FLOW CHARACTERISTICS OF SUBMERGED FREE JET FLOW FROM PETAL-SHAPED NOZZLE

2013 ◽  
Vol 2013.4 (0) ◽  
pp. _1012-1_-_1012-6_
Author(s):  
SHAKOUCHI Toshihiko ◽  
IRIYAMA Shota ◽  
KAWASHIMA Yuki ◽  
TSUJIMOTO Koichi ◽  
ANDO Toshitake
Keyword(s):  
Flow Characteristics ◽  
Jet Flow ◽  
Free Jet ◽  
Shaped Nozzle ◽  
Free Jet Flow

A numerical study of the nozzle/diffuser micropump

2008 ◽  
Vol 222 (3) ◽  
pp. 525-533 ◽  
Author(s):  
K-S Yang ◽  
I-Y Chen ◽  
K-H Chien ◽  
C-C Wang
Keyword(s):  
Numerical Study ◽  
Geometric Dimension ◽  
Jet Flow ◽  
Opening Angle ◽  
Cross Sectional ◽  
Free Jet ◽  
Chamber Length ◽  
Two Factors ◽  
Versus Amplitude ◽  
Free Jet Flow

This study numerically investigates the performance of micronozzle/diffuser pump subject to the influence of frequency, opening angle, geometric dimension, and amplitude. For the effect of geometric dimension, the effect of chamber length is far more important than that of chamber depth because it can provide much more effective pumping volume. It is found that the net flowrate of a micropump increased with pumping frequency and opening angle. However, a level-off phenomenon of the net flowrate versus amplitude is seen at amplitudes nearby 150–200 μm and at an opening angle above 10°. This phenomenon is associated with two factors that compensate with each other. One is the free jet flow from the outlet that overturns and blocks the flow from the inlet. The other is the reduction of the strength of jet flow at a larger amplitude owing to effective increase of cross-sectional area.

Free Jet Flow Modulation

1975 ◽  
Vol 8 (1) ◽  
pp. 482-486
Author(s):  
J.D. Malcolm
Keyword(s):  
Jet Flow ◽  
Flow Modulation ◽  
Free Jet ◽  
Free Jet Flow

Analysis of the Vortex Dynamics and Instability Mechanisms for a Lobed Nozzle Jet

2020 ◽  
Author(s):  
Aarthi Sekaran ◽  
Noushin Amini
Keyword(s):  
Vortex Dynamics ◽  
Large Scale ◽  
Three Dimensional ◽  
Jet Flow ◽  
Passive Flow Control ◽  
Free Jet ◽  
Passive Flow ◽  
Instability Modes ◽  
Free Jet Flow ◽  
Lobed Nozzle

Abstract The application of radially lobed nozzles has seen renewed challenges in the recent past with their roles in combustion chambers and passive flow control. The free jet flow from such nozzles has been studied for different flow conditions and compared to jets from round nozzles, verifying their improved mixing abilities. The precise mixing mechanisms of these nozzles are, however, not entirely understood and yet to be analyzed for typical jet parameters and excitation modes. While past studies have proposed the presence of spanwise Kelvin-Helmholtz instability modes, the roll-up frequencies of the structures indicate more than one primary structure, which is challenging to resolve experimentally. The present study carries out three dimensional CFD simulations of the flow from a tubular lobed nozzle to identify instability mechanisms and vortex dynamics that lead to enhanced mixing. We initially validate the model against existing hotwire and LDV data following which a range of Large Eddy Simulations (LES) are carried out. The free jet flow was at a Reynolds number of around 5 × 104, based on the effective jet diameter. Initial results are compared to that of a round nozzle to demonstrate changes in mixing mechanisms. The lobed nozzle simulations confirmed the presence of K-H-like modes and their evolution. We also track the formation and the transport of coherent structures from the tubular part of the nozzle to the core flow, to reveal the evolution of the large-scale streamwise modes at the crests and corresponding horseshoe-like structures at the troughs.

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