Detailed Characterisation of a Swirled Air/Kerosene Spray in Reactive and Non-Reactive Conditions Downstream From an Actual Turbojet Injection System

2011 ◽  
Author(s):  
Renaud Lecourt ◽  
Guillaume Linassier ◽  
Ge´rard Lavergne
Keyword(s):  
Data Base ◽  
Gas Phase ◽  
Two Phase Flow ◽  
Flame Structure ◽  
Original Method ◽  
Injection System ◽  
Spray Combustion ◽  
Phase Flow ◽  
Two Phase ◽  
Axial Velocity Component

As part of the investigations of the ignition of jet-engines under altitude conditions, a detailed data base was built with the results of experiments on the two-phase flow produced by an actual swirl air/kerosene turbojet injection system. The injection system had a fairly simple geometry. It was used with liquid kerosene injected through a pressure-swirl fuel atomiser. In this case the measurements were carried out at atmospheric pressure in a windowed combustion chamber, with air at ambient temperature. The tested equivalence ratio was 0.95 which corresponds to an air mass flow rate of 0.035 kg/s. For this operating point, we obtained the velocity field of the gas phase under non-reactive conditions by LDA. The axial velocity component of the gas phase was also measured in the burning spray using an original method with a phase Doppler device. The data recorded with the PDA were also processed to obtain the kerosene droplet sizes and velocities under reactive conditions. The same phase Doppler device was used in non-reactive conditions to measure the size and velocity distributions of the kerosene droplets in a section close to the injection system exit in order to complete the data base with the boundary conditions for the liquid phase. In addition the flame was visualised qualitatively. The picture of the stabilized flame was processed with an Abel transform to compare the LDA/PDA measurements with the flame structure, obtained under the reactive conditions. Finally, unsteady pressure measurements were taken under non-reactive conditions and the LDA measurements processed, close to the injection system exit, to get the PVC (Precessing Vortex Core) frequency. The data were analysed to determine the influence of the spray combustion on the two-phase flow. The geometry of the whole experimental setup and the data base are available to other researchers for testing and validating spray combustion models and unsteady two-phase flow numerical simulations.

Numerical Analysis of Two-Phase Pipe Flow of Liquid Helium Using Multi-Fluid Model

2001 ◽  
Vol 123 (4) ◽  
pp. 811-818 ◽  
Author(s):  
Jun Ishimoto ◽  
Mamoru Oike ◽  
Kenjiro Kamijo
Keyword(s):  
Phase Transition ◽  
Gas Phase ◽  
Liquid Helium ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Numerical Results ◽  
Phase Flow ◽  
Two Dimensional ◽  
Two Phase ◽  
Normal Fluid

The two-dimensional characteristics of the vapor-liquid two-phase flow of liquid helium in a pipe are numerically investigated to realize the further development and high performance of new cryogenic engineering applications. First, the governing equations of the two-phase flow of liquid helium based on the unsteady thermal nonequilibrium multi-fluid model are presented and several flow characteristics are numerically calculated, taking into account the effect of superfluidity. Based on the numerical results, the two-dimensional structure of the two-phase flow of liquid helium is shown in detail, and it is also found that the phase transition of the normal fluid to the superfluid and the generation of superfluid counterflow against normal fluid flow are conspicuous in the large gas phase volume fraction region where the liquid to gas phase change actively occurs. Furthermore, it is clarified that the mechanism of the He I to He II phase transition caused by the temperature decrease is due to the deprivation of latent heat for vaporization from the liquid phase. According to these theoretical results, the fundamental characteristics of the cryogenic two-phase flow are predicted. The numerical results obtained should contribute to the realization of advanced cryogenic industrial applications.

scholarly journals Modeling of Interior Ballistic Gas-Solid Flow Using a Coupled Computational Fluid Dynamics-Discrete Element Method

2013 ◽  
Vol 80 (3) ◽  
Author(s):  
Cheng Cheng ◽  
Xiaobing Zhang
Keyword(s):  
Discrete Element Method ◽  
Gas Phase ◽  
Two Phase Flow ◽  
Discrete Element ◽  
Particle Collision ◽  
Contact Detection ◽  
Reconstruction Method ◽  
Phase Flow ◽  
Two Phase ◽  
Element Method

In conventional models for two-phase reactive flow of interior ballistic, the dynamic collision phenomenon of particles is neglected or empirically simplified. However, the particle collision between particles may play an important role in dilute two-phase flow because the distribution of particles is extremely nonuniform. The collision force may be one of the key factors to influence the particle movement. This paper presents the CFD-DEM approach for simulation of interior ballistic two-phase flow considering the dynamic collision process. The gas phase is treated as a Eulerian continuum and described by a computational fluid dynamic method (CFD). The solid phase is modeled by discrete element method (DEM) using a soft sphere approach for the particle collision dynamic. The model takes into account grain combustion, particle-particle collisions, particle-wall collisions, interphase drag and heat transfer between gas and solid phases. The continuous gas phase equations are discretized in finite volume form and solved by the AUSM+-up scheme with the higher order accurate reconstruction method. Translational and rotational motions of discrete particles are solved by explicit time integrations. The direct mapping contact detection algorithm is used. The multigrid method is applied in the void fraction calculation, the contact detection procedure, and CFD solving procedure. Several verification tests demonstrate the accuracy and reliability of this approach. The simulation of an experimental igniter device in open air shows good agreement between the model and experimental measurements. This paper has implications for improving the ability to capture the complex physics phenomena of two-phase flow during the interior ballistic cycle and to predict dynamic collision phenomena at the individual particle scale.

An Evaluation of Existing Two-Phase Flow Correlations for Use With ASME Sharp Edge Metering Orifices

1977 ◽  
Vol 99 (3) ◽  
pp. 343-347 ◽  
Author(s):  
L. T. Smith ◽  
J. W. Murdock ◽  
R. S. Applebaum
Keyword(s):  
Natural Gas ◽  
Data Base ◽  
Root Mean Square ◽  
Two Phase Flow ◽  
Salt Water ◽  
Sharp Edge ◽  
Phase Flow ◽  
Mean Square ◽  
Two Phase ◽  
Liquid Flows

The two-phase flow correlations developed by Murdock, James, Marriott, and Smith and Leang are evaluated for the case of flow through sharp edge measuring orifices which physically meet ASME standards for flow measurement. The evaluation is based on two sets of consistent orifice flow data. The first data base consists of 34 test points for the flow of steam-water mixtures. The second data base consists of 81 data points for the flow of air-water, natural gas-water, natural gas-salt water, and natural gas-distillate mixtures. The root mean square fractional deviation of each correlation is used to determine its predictive reliability. Computed root mean square fraction deviations for steam-water flows are: James, ±0.081; Marriott, ±0.114; Murdock, ±0.141; Smith and Leang, ±0.218. For the case of gas-liquid flows, the values are: Murdock, ±0.074; James, ±0.178; Smith and Leang, ±0.183; Marriott, ±0.458.

Flow Structures and Frictional Characteristics on Two-Phase Flow in Microchannels in PEM Fuel Cells

2005 ◽  
Author(s):  
Eon Soo Lee ◽  
Carlos H. Hidrovo ◽  
Julie E. Steinbrenner ◽  
Fu-Min Wang ◽  
Sebastien Vigneron ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Gas Phase ◽  
Single Phase ◽  
Film Flow ◽  
Two Phase Flow ◽  
Water Injection ◽  
Injection Rate ◽  
Flow Structures ◽  
Phase Flow ◽  
Two Phase

This experimental paper presents a study of gas-liquid two phase flow in rectangular channels of 500μm × 45μm and 23.7mm long with different wall conditions of hydrophilic and hydrophobic surface, in order to investigate the flow structures and the corresponding friction factors of simulated microchannels of PEMFC. The main flow in the channel is air and liquid water is injected at a single or several discrete locations in one side wall of the channel. The flow structure of liquid water in hydrophilic wall conditioned channel starts from wavy flow, develops to stable stratified film flow, and then transits to unstable fluctuating film flow, as the pressure drop and the flow velocity of air increase from around 10 kPa to over 100 kPa. The flow structure in hydrophobic channel develops from the slug flow to slug-and-film flow with increasing pressure drop and flow velocity. The pressure drop for single phase flow is measured for a base line study, and the fRe product is in close agreement with the theoretical value (fRe = 85) of the conventional laminar flow of aspect ratio 1:11. At the low range of water injection rate, the gas phase fRe product of the two phase flow based on the whole channel area was not substantially affected by the water introduction. However, as the water injection rate increases up to 100 μL/min, the gas phase fRe product based on the whole channel area deviates highly from the single phase theoretical value. The gas phase fRe product with the actual gas phase area corrected by the liquid phase film thickness agrees with the single phase theoretical value.

AMADEUS Project and Microscopic Simulation of Boiling Two-Phase Flow by the Lattice-Boltzmann Method

1997 ◽  
Vol 08 (04) ◽  
pp. 843-858 ◽  
Author(s):  
Yasuyoshi Kato ◽  
Koji Kono ◽  
Takeshi Seta ◽  
Daniel Martínez ◽  
Shiyi Chen
Keyword(s):  
Phase Transition ◽  
Gas Phase ◽  
Lattice Boltzmann ◽  
Bubble Dynamics ◽  
Two Phase Flow ◽  
Phase Interface ◽  
Lattice Boltzmann Model ◽  
Phase Flow ◽  
Two Phase ◽  
Boltzmann Model

A two-dimensional lattice-Boltzmann model with a hexagonal lattice is developed to simulate a boiling two-phase flow microscopically. Liquid-gas phase transition and bubble dynamics, including bubble formation, growth and deformation, are modeled by using an interparticle potential based on the van der Waals equation of state. Thermohydrodynamics is incorporated into the model by adding extra velocities to define temperature. The lattice-Boltzmann model is solved by a finite difference scheme so that numerical stability can be ensured at large discontinuity across the liquid-gas phase boundary and the narrow phase interface thickness can be attained. It is shown from numerical simulations that the model has the ability to reproduce phase transition, bubble dynamics and thermohydrodynamics while assuring numerical instability and narrow phase interface.

Two-phase flow of liquid-gas in diesel fuel injection system and their effect on engine performances

2001 ◽  
Vol 10 (3) ◽  
pp. 223-227 ◽  
Author(s):  
Yongling He ◽  
Zhihe Zhao ◽  
Jianxin Liu ◽  
Huiyong Du ◽  
Min Li ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Fuel Injection ◽  
Two Phase Flow ◽  
Injection System ◽  
Fuel Injection System ◽  
Phase Flow ◽  
Two Phase ◽  
Diesel Fuel Injection

scholarly journals Computational Fluid Dynamics Simulations of Gas-liquid Two-phase Flow Characteristics through a Vertical to Horizontal Right Angled Elbow

2017 ◽  
Vol 30 (1&2) ◽  
pp. 1-16 ◽  
Author(s):  
N. Z. Aung ◽  
T. Yuwono
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Gas Phase ◽  
Test Section ◽  
Two Phase Flow ◽  
Liquid Velocity ◽  
Phase Flow ◽  
Cfd Simulations ◽  
Two Phase ◽  
Horizontal Pipe

Having a clear understanding on the phase distribution of gas-liquid two-phase flow through elbow bends is vital in mixing and separation system designs. This paper presents the computational fluid dynamics (CFD) simulations and experimental observations of gas-liquid two-phase flow pattern characteristic through a vertical to horizontal right angled (90°) elbow. Experimental observations were conducted in a transparent test section that consisted of a vertical pipe, elbow bend and horizontal pipe with an inside diameter of 0.036 m. The CFD simulations were performed by using a computer software package, FLUENT 6.2. Bubbly flow conditions were created in the vertical test section with the variation of superficial liquid Reynolds number from 13 497 to 49 488 and volumetric gas quality from 0.05 to 0.2. The CFD results showed a good agreement with experimental results in the following observations. The results showed that gas-liquid flow pattern inside and downstream of the elbow bend mainly depended on liquid velocity and it is also influenced by gas quality at high liquid velocities. At lower liquid velocities, gas-liquid separation began early in the elbow bend and gas-phase migrated to outer bend. Then, it smoothly transformed to stratified flow at elbow outlet. When the liquid velocity was further increased, the liquid phase occupied the outer bend rubbing the gas phase to the inner bend and delayed the formation of gas layer in the horizontal pipe. The increase of gas quality in higher liquid velocities promoted gas core formation at the elbow exit and caused wavy gas layers at the downstream of the elbow.

Influence of the Fin on Two-Dimensional Characteristics of Dispersed Flow With Wall Liquid Film in the Vicinity of Obstacle

2002 ◽  
Author(s):  
Zoran V. Stosic ◽  
Vladimir D. Stevanovic ◽  
Akimi Serizawa
Keyword(s):  
Liquid Film ◽  
Gas Phase ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Film Surface ◽  
Phase Flow ◽  
Atmospheric Conditions ◽  
Two Phase ◽  
Positive Effects ◽  
Rod Bundle

Spacers have positive effects on the heat transfer enhancement and critical heat flux (CHF) increase downstream of their location in the boiling channel. These effects are further increased by the inclusion of the fin on the spacer rear edge. Numerical simulation of a separation in a high void gas phase and dispersed droplets flow around a spacer, with a liquid film flowing on the wall, is performed. Mechanisms leading to the CHF increase due to the two-phase flow separation and liquid film thickening downstream the spacer are demonstrated. Numerical simulations of gas phase, entrained droplets and wall liquid film flows were performed with the three-fluid model and with the application of the high order numerical scheme for the liquid film surface interface tracking. Predicted is a separation of gas and entrained droplets streams around the spacer without and with a fin inclined 30 and 60 degrees to the wall, as well as a change of wall liquid film thickness in the vicinity of spacer. Results of liquid film dynamic behaviour are compared with the recently obtained experimental results. Multi-dimensional characteristics of surface waves on the liquid film were measured with newly developed ultrasonic transmission technique in a 3×3 rod bundle test section with air-water flow under atmospheric conditions. Obtained numerical results are in good agreement with experimental observations. The presented investigation gives insight into the complex mechanisms of separated two-phase flow with wall liquid film around the spacer and support thermal-hydraulic design and optimisation of flow obstacles in various thermal equipments.

scholarly journals Numerical Simulation of Gas-Particle Two-Phase Flow in a Nozzle with DG Method

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Duan Maochang ◽  
Yu Xijun ◽  
Chen Dawei ◽  
Qing Fang ◽  
Zou Shijun
Keyword(s):  
Flow Field ◽  
Gas Phase ◽  
Mass Fraction ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Governing Equations ◽  
Two Phase ◽  
Dg Method ◽  
The Impact

In this paper, the discontinuous Galerkin (DG) method is applied to solve the governing equations of the dispersed two-phase flow with the two-fluid Euler/Euler approach. The resulting governing equations are simple in form and the solution process is very natural. The characteristics of the gas-particle two-phase flow in an engine nozzle are mainly analyzed, and the impacts of the particle mass fraction and particle size on the flow field and engine performance are evaluated. Because of the addition of particles, the gas flow field undergoes significant modifications. Increase in the mass fraction leads to a significant thrust loss in the gas phase, and the impact of the particles on the gas phase could be substantial. Therefore, a quantitative study of thrust loss in the nozzle due to the particle impact is made. It is found that the gas thrust in the two-phase flow is reduced, but the total thrust of the two-phase flow increases to a certain extent.

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