CFD SIMULATION OF DIESEL SPRAYS OVER A WIDE RANGE OF AMBIENT GAS DENSITIES USING AN IMPROVED GAS JET SPRAY MODEL

2011 ◽  
Vol 21 (7) ◽  
pp. 591-609 ◽  
Author(s):  
Choong Hoon Lee ◽  
Y. Wang ◽  
Rolf D. Reitz
Keyword(s):  
Cfd Simulation ◽  
Gas Jet ◽  
Diesel Sprays ◽  
Wide Range ◽  
Ambient Gas

CFD Simulation of Fluid Flow Through Porous Media: Application to Decomposed Gases Flow Through Foam Pattern in Lost Foam Casting

Materials ◽  
2003 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Cfd Simulation ◽  
Reynolds Numbers ◽  
Phase Flow ◽  
Flow Through Porous Media ◽  
Foam Material ◽  
Element Analysis ◽  
Wide Range ◽  
Flow Through ◽  
Foam Pattern ◽  
Lost Foam

Numerical simulation of decomposed gases through foam pattern was conducted using finite element analysis. A new kinetic model is proposed for gaseos phase flow between molten metal and foam material. The computations were performed for a wide range of Reynolds numbers. The results of the simulations are compared with the experiemental data obtained in this study.

Influence of Laser Irradiation and Ambient Gas in Preparation of PZT Films by Laser Ablation

1990 ◽  
Vol 191 ◽  
Author(s):  
Akiharu Morimoto ◽  
Shigeru Otsubo ◽  
Tatsuo Shimizu ◽  
Toshiharu Minamikawa ◽  
Yasuto Yonezawa ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Laser Irradiation ◽  
Perovskite Structure ◽  
Film Surface ◽  
Target Material ◽  
Laser Ablation Method ◽  
Wide Range ◽  
Pzt Films ◽  
Ambient Gas ◽  
Substrate Temperatures

ABSTRACTPb(Zr0.52Ti0. 48)O3 (PZT) films were prepared on r-plane sapphire substrates by the laser ablation method utilizing ArF excimer laser in O2 or N2O environment. The composition of the films deposited in O2 environment was found to be fairly close to the composition of the target material for a wide range of substrate temperatures, 400 – 750 °c. Increasing the laser fluence (the laser power density) for the ablation enhances the formation of the perovskite structure rather than the pyrochlore one. Use of N2O ambient gas instead of O2 gas enhances the formation of the perovskite structure of PZT films. Furthermore, it was found that a laser irradiation on the growing film surface during deposition enhances the formation of the perovskite structure.

scholarly journals Influence of inlet air distributor geometry on the fluid dynamics of conical spouted beds: A CFD study

2018 ◽  
Vol 24 (4) ◽  
pp. 369-378 ◽  
Author(s):  
J.N.M. Batista ◽  
R.C. Brito ◽  
R. Béttega
Keyword(s):  
Fluid Dynamics ◽  
Cfd Simulation ◽  
Low Cost ◽  
Scale Up ◽  
Straight Tube ◽  
Spouted Bed ◽  
Bed Height ◽  
Spouted Beds ◽  
Wide Range ◽  
Solid Dynamics

The spouted bed presents limitations in terms of scale-up. Furthermore, its stability depends on its geometry as well as the properties of the fluid and solid phases. CFD provides an important tool to improve understanding of these aspects, enabling a wide range of information to be obtained rapidly and at low cost. In this work, CFD simulation was used to evaluate the effects of different inlet air distributors (Venturi and straight tube) and the effects of static bed height on the fluid and solid dynamics of a conical spouted bed. Simulations were performed using the two-dimensional Euler-Euler approach. In order to evaluate the fluid dynamics model, static pressure data obtained by simulation were compared with experimental data obtained with the Venturi distributor. The fluid and solid dynamics of the conical spouted bed were obtained by CFD simulation. The results showed that the pressure drop was lower for the straight tube air distributor, while the Venturi air distributor provided higher stability and a more homogenous air distribution at the bed entrance.

Numerical Investigation on the Effect of Advanced Breakup Model on Spray Simulation of a Multi-Hole Injector

2018 ◽  
Author(s):  
Srinibas Tripathy ◽  
Sridhar Sahoo ◽  
Dhananjay Kumar Srivastava
Keyword(s):  
Mass Fraction ◽  
Gas Pressure ◽  
Gas Jet ◽  
Computational Time ◽  
Fuel Vapor ◽  
Computational Domain ◽  
Penetration Length ◽  
Spray Penetration ◽  
Ambient Gas ◽  
Vapor Mass

Computational fluid dynamics (CFD) plays a tremendous role in evaluating and visualizing the spray breakup, atomization and vaporization process. In this study, ANSYS Forte CFD tool was used to simulate the spray penetration length and spray morphology in a constant volume chamber at different grid size of a multi-hole injector. An unsteady gas jet model was coupled with Kelvin-Helmholtz (KH) and Rayleigh-Taylor (RT) model for multi-hole spray simulation. The effect of CFD cell size and ambient gas pressure on spray penetration length and spray morphology of fuel vapor mass fraction were investigated for both KH-RT and KH-RT with the unsteady gas jet model. It is found that KH-RT with the unsteady gas jet model shows mesh independent spray penetration length and spray morphology of fuel vapor mass fraction as compared to KH-RT model. This can be explained by the Lagrangian-Eulerian coupling of axial droplet-gas relative velocity is modeled on the principle of unsteady gas jet theory instead of discretizing very fine grid to the computational domain. This reduces the requirement of fine mesh near the nozzle and allows larger time step during spray injection. It is also observed that at higher ambient gas pressure, an aerodynamic force between the droplet and gas intensifies which reduces the overall spray penetration length and fuel vapor mass. The distorted spray morphology of fuel vapor mass fraction was accurately predicted at high ambient gas pressure using the KH-RT with an unsteady gas jet model which results in mesh independent drag predictions. The use of advanced spray model results in the mesh size dependency reduction and accurate drag prediction with less computational time and faster accurate solutions over all conventional spray breakup models.

scholarly journals Interferometry of Gas-Phase Flows during Selective Laser Melting

2019 ◽  
Vol 10 (1) ◽  
pp. 231 ◽  
Author(s):  
Pavel A. Podrabinnik ◽  
Alexander E. Shtanko ◽  
Roman S. Khmyrov ◽  
Andrey D. Korotkov ◽  
Andrey V. Gusarov
Keyword(s):  
Gas Phase ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Metal Vapor ◽  
Gas Jet ◽  
Laser Melting ◽  
Pressure Fields ◽  
Ambient Gas ◽  
Processing Zone

Gas-phase flows occurring in a plume in a processing zone during selective laser melting (SLM) can significantly affect the quality of the process. To further enhance SLM performance, the characteristics of the flows should be considered. In this article, the vapor-gas jet emerging from the laser processing zone was studied. It was visualized by interferometry to evaluate flow velocity, geometry and changes in refractory index depending on laser power. The velocity and pressure fields of the vapor jet and the entrained ambient gas were estimated by mathematical modeling. It was shown that the increase of laser power led to higher jet velocity and greater change in its refractory index. The latter also was used to evaluate the content of metal vapor in the plume and its influence on the absorption of laser radiation.

CFD Simulation of PWR Subchannel Void Distribution Benchmark

2010 ◽  
Author(s):  
Wang-Kee In ◽  
Chang-Hwan Shin ◽  
Tae-Hyun Chun
Keyword(s):  
Void Fraction ◽  
Cfd Simulation ◽  
Fluid Model ◽  
Small Diameter ◽  
Operating Conditions ◽  
Heated Wall ◽  
Bubble Generation ◽  
Void Distribution ◽  
Wide Range ◽  
Two Fluid Model

A CFD study was performed to simulate the steady-state void distribution benchmark based on the NUPEC PWR Subchannel and Bundle Tests (PSBT). The void distribution benchmark provides measured void fraction data over a wide range of geometrical and operating conditions in a single subchannel and fuel bundle. This CFD study simulated the boiling flow in a single subchannel. A CFD code was used to predict the void distribution inside the single subchannel. The multiphase flow model used in this CFD analysis was a two-fluid model in which liquid (water) and vapor (steam) were considered as continuous and dispersed fluids, respectively. A wall boiling model was also employed to simulate bubble generation on a heated wall surface. The CFD prediction with a small diameter of vapor bubble shows a higher void fraction near the heated wall and a migration of void in the subchannel gap region. A measured CT image of void distribution indicated a locally higher void fraction near the heated wall for the test conditions of a subchannel averaged void fraction of less than about 20%. The CFD simulation predicted a subchannel averaged void fraction and fluid density which agree well with the measured ones for a low void condition.

Dependence of rate of ionic recombination on temperature and density of ambient gas

1980 ◽  
Vol 369 (1738) ◽  
pp. 327-334 ◽  
Keyword(s):  
Universal Curve ◽  
Wide Range ◽  
Ambient Gas

Extensive computer-simulated experiments are carried out on termolecular and binary ionic recombination. It is shown that the results for termolecular recombination may be presented in the form of a quasi-universal curve. There is no such curve for binary recombination but scaling procedures exist which allow results to be obtained for a remarkably wide range of cases.

Influence of operational parameters on performance of twin thermoacoustic prime mover – CFD studies

2016 ◽  
Vol 33 (3) ◽  
Author(s):  
Jabbar P ◽  
Hariharan N.M ◽  
Palani Sivashanmugam ◽  
S. Kasthurirengan
Keyword(s):  
Temperature Gradient ◽  
Design Methodology ◽  
Cfd Simulation ◽  
Working Fluid ◽  
Geometrical Parameters ◽  
Pressure Amplitude ◽  
Prime Mover ◽  
Operational Parameters ◽  
Fluid Medium ◽  
Wide Range

Purpose The present investigation deals with the analysis of the performance of twin thermoacoustic prime mover (TAPM) which are measured in terms of frequency and pressure amplitude by varying the parameters such as temperature gradient along the length of stack and the operating pressures of fluid medium argon using CFD simulation. With the help of CFD researchers and Engineers can evaluate the performance of a wide range of thermoacoustic systems on the computer without the time, expense, and disruption required to make actual changes onsite (stack) which is tedious to fabricate. Design/methodology/approach For the present simulation, the operating pressures of argon such as 1bar, 3bar and 5bar, and the temperature gradient is varied from 600K to 1400K with the regular intervals of each 200K. The geometry of twin TAPM is created using GAMBIT processor, and the simulation is carried out using FLUENT. The geometrical parameters of twin TAPM are kept constant throughout the simulation. The results for frequency and pressure amplitude obtained from the CFD simulation of twin TAPM for various temperature gradient and operating pressures are analysed and reported. Findings The computational results of twin thermoacoustic prime mover shows an increase in pressure amplitude with an increase in the temperature gradient and also it increases with an increase in operating pressures of the fluid medium. The parameter operating pressures of the working fluid medium and the stack hot end temperature has no significant effect on the output, frequency. Originality/value Though several experimental works had been published based on the twin thermoacoustic prime mover, an attempt has been made in the present investigation for the first time to estimate the performance of twin thermoacoustic prime mover using CFD package (ANSYS-FLUENT) by varying temperature gradient. The temperature gradient and operating pressures were varied and the performance of twin thermoacoustic prime mover was measured in terms of frequency and pressure amplitude.

Sign in / Sign up

Export Citation Format

Share Document