Simulation of Liquid Fuel Atomization by a Complex High-Shear Swirling Injector

2014 ◽  
Author(s):  
Frank Ham ◽  
Dokyun Kim ◽  
Sanjeeb Bose ◽  
Hung Le ◽  
Marcus Herrmann
Keyword(s):  
Experimental Studies ◽  
Circular Cross Section ◽  
Field Measurements ◽  
Fuel Injector ◽  
Atomization Process ◽  
Spray Formation ◽  
Fuel Droplets ◽  
Breakup Mechanism ◽  
Fuel Atomization ◽  
Primary Breakup

The research and development described in this paper arises from the need for modeling a realistic fuel atomization process in a complex combustor/augmentor fuel injector. In the atomization process, it is important to understand the primary breakup mechanism and to predict the resulting fuel droplets. However, the mechanism of atomization and the resulting spray formation processes in realistic complex fuel injectors are not well understood because experimental access to the atomization region is typically severely limited. A significant portion of the atomization process occurs in spatial regions adjacent to solid walls that block experimental access into the injector so that experimental studies are limited to either far field measurements of complex injectors, after most of the atomization has occurred, or to simple injector geometries such as a circular cross-section pipes injecting into crossflow channels.

scholarly journals Numerical Simulation and Experimental Validation of Air-Assisted Fuel Atomization for Aviation Applications

2018 ◽  
Vol 6 (9) ◽  
pp. 176
Author(s):  
Jagadeesh .B ◽  
Vidyasagar Shetty ◽  
Raghavendra Pai K
Keyword(s):  
Numerical Simulations ◽  
Gas Phase ◽  
Gas Flow ◽  
Transient Flow ◽  
Cone Angle ◽  
Flame Height ◽  
Fuel Injector ◽  
Spray Formation ◽  
Spray Structure ◽  
Fuel Atomization

The project deals with an attempt of developing an advanced atomizer concept to control the spray formation for mixed spray combustion is examined. The aim is to improve the spray structure that preserves the flame height and modifies the width of the flame. The atomizer concept for development of a modified spray combines a swirling liquid film generation that is atomized by an external swirling gas flow. To investigate the main characteristics of the combined atomizer, experiments and numerical simulations of the flow operation with different geometric nozzle parameters (number of gas holes) and process parameters (flow rate of fuel and air ) as well as fuel properties are carried out to produce a modified, enlarged and steady spray of small droplets. In this work, fuel (kerosene) is used as the liquid phase and air as the gas phase. In the simulations, the multiphase flow is modelled using k-epsilon model with transient flow and the turbulence of the gas phase is 10% and fluid is used as dispersed medium and gas as constant fluid at Standard Temperature and Pressure (STP). The goal of the numerical simulations is to investigate the cone angle and flow behaviour of the fuel injector, impingement of surrounding air on the fuel is noticed and the morphology of the spray is examined and the fuel injector is made as prototype design and fabrication work is carried and tested in the laboratory and compared with the CFD analysis..

scholarly journals Residual fuel atomization process simulation

2017 ◽  
Vol 169 (2) ◽  
pp. 108-112
Author(s):  
Oleh KLYUS ◽  
Nadezhda ZAMIATINA
Keyword(s):  
Environmental Performance ◽  
Droplet Diameter ◽  
Combustion Process ◽  
Experimental Studies ◽  
Jet Fuel ◽  
Compression Ignition ◽  
Atomization Process ◽  
Fuel Atomization ◽  
The Mean ◽  
Definition Of

The process of atomization of fuel in engines with compression ignition is determining in organization of the combustion process, the result of which are the economic and environmental performance of the engine. One of the main parameters of the spray jet fuel is the mean droplet diameter. The article presents the results of analytical and experimental studies by the definition of mean diameter of Sauter droplet of atomized residual fuel IFO380.

scholarly journals Experimental studies of the influence of pressure of slurry fuel and air on the spray cone structure during atomization

2019 ◽  
Vol 21 (5) ◽  
pp. 110-123
Author(s):  
D. V. Gvozdyakov ◽  
A. V. Zenkov ◽  
V. E. Gubin ◽  
M. V. Vedyashkin
Keyword(s):  
Experimental Studies ◽  
Aerodynamic Characteristics ◽  
Boiler Furnace ◽  
Spray Cone ◽  
Fuel Droplets ◽  
Fuel Atomization ◽  
Current State ◽  
Cone Formation ◽  
Mathematical And Physical Modeling ◽  
Power Boiler

Results of experimental studies of pneumomechanical atomization process of slurry fuel with a plasticizer in an aerodynamic simulator of power boiler furnace are presented. Analysis of the current state in the field of research of slurry fuel atomization processes has been conducted. Influence of pressure of slurry fuel and air on the structure of the emerging spray cone have been analyzed. The values of characteristic dimensions of three zones of spray cone have been determined: core, middle and outer zones. Effect of pressure of the sprayed slurry fuel and air on the period of stable spray cone formation and geometric characteristics of the zones has been experimentally confirmed. Ranges of velocities and sizes of droplets in the flow at various pressures have been distinguished. The quantitative values of slurry fuel droplets with different velocities in the process of its pneumatic spraying have been obtained. It has been established that the largest number of particles in the study area have velocities up to 8 m/s; a significant number of droplets (up to 20%) have velocities from 8 to 32 m/s; velocities of 32 m/s and more are typical for 1% of droplets. During the results processing, aerosol particles with a size of 1 micron or less have not been taken into account. The values of We criterion for the respective sizes and velocities of the sprayed fuel droplets have been determined. It has been established that significant part of the droplets undergoes catastrophic crushing, which is characteristic for the values of We numbers from 7800 and higher. The obtained results can be used for mathematical and physical modeling of the process of slurry fuels atomization in the furnaces of power boilers in order to predict the aerodynamic characteristics of the designed and existing units.

Measurement of Aerodynamic Breakup of Non-Newtonian Drops by Digital In-Line Holography

2014 ◽  
Author(s):  
Jian Gao ◽  
Neil S. Rodrigues ◽  
Paul E. Sojka ◽  
Jun Chen
Keyword(s):  
Strain Rate ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Droplet Size Distribution ◽  
Newtonian Fluids ◽  
Bulk Liquid ◽  
Spray Formation ◽  
Spray Process ◽  
Low Viscosity ◽  
Breakup Mechanism

Aerodynamic fragmentation of bulk liquid into small droplets is an essential spray process that occurs in a variety of combustion systems. The aerodynamic breakup of non-Newtonian fluids, such as aerospace propellants, bio-fuels, fire-fighting liquids, thermal barrier coatings, water-gel explosives, paints, etc, is involved in many important applications. Non-Newtonian fluids differ from Newtonian fluids in that they do not exhibit a linear shear stress-strain rate relationship. They are employed when the liquid is desirable to have a low viscosity during spray formation (high strain rate) and a higher viscosity when on a target (low strain rate). This useful rheological behavior leads to a significantly different breakup mechanism of non-Newtonian fluids compared to that of Newtonian liquids. Unfortunately, there are limited experimental studies on the aerodynamic breakup of non-Newtonian drops. This is probably due to the difficulty in measuring fragments of complex morphologies. Digital in-line holography (DIH) provides simultaneous measurements of the particle size and position with unique access to three-dimensional (3D) information. Previous applications have demonstrated its applicability to arbitrary-shape particles, capability of extracting 3D morphologies, and effectiveness in characterizing the aerodynamic breakup of Newtonian drops. In the present study, the aerodynamic breakup of non-Newtonian drops is characterized using DIH. The measured characteristics including breakup morphologies, fragment/droplet size distribution and velocity distributions, demonstrate the effectiveness of DIH as a diagnostic tool for non-Newtonian fluids.

Direct microscopic image and measurement of the atomization process of a port fuel injector

2010 ◽  
Vol 21 (7) ◽  
pp. 075403 ◽  
Author(s):  
Mohamed Esmail ◽  
Nobuyuki Kawahara ◽  
Eiji Tomita ◽  
Mamoru Sumida
Keyword(s):  
Microscopic Image ◽  
Fuel Injector ◽  
Atomization Process

Experimental Investigation Into the Effects of the Steady Wake-Tip Clearance Vortex Interaction in a Compressor Cascade

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Andreas Krug ◽  
Peter Busse ◽  
Konrad Vogeler
Keyword(s):  
Flow Field ◽  
Experimental Studies ◽  
Axial Compressor ◽  
Field Measurements ◽  
Tip Clearance ◽  
Compressor Cascade ◽  
Unsteady Interaction ◽  
Linear Compressor Cascade ◽  
Tip Clearance Vortex ◽  
The Impact

An important aspect of the aerodynamic flow field in the tip region of axial compressor rotors is the unsteady interaction between the tip clearance vortex (TCV) and the incoming stator wakes. In order to gain an improved understanding of the mechanics involved, systematic studies need to be performed. As a first step toward the characterization of the dynamic effects caused by the relative movement of the blade rows, the impact of a stationary wake-induced inlet disturbance on a linear compressor cascade with tip clearance will be analyzed. The wakes were generated by a fixed grid of cylindrical bars with variable pitch being placed at discrete pitchwise positions. This paper focuses on experimental studies conducted at the newly designed low-speed cascade wind tunnel in Dresden. The general tunnel configuration and details on the specific cascade setup will be presented. Steady state flow field measurements were carried out using five-hole probe traverses up- and downstream of the cascade and accompanied by static wall pressure readings. 2D-particle image velocimetry (PIV) measurements complemented these results by visualizing the blade-to-blade flow field. Hence, the structure of the evolving secondary flow system is evaluated and compared for all tested configurations.

Characteristics of injection of diesel fuel, rapeseed oil and their mixtures in diesel engines of various types

2021 ◽  
pp. 167-178
Author(s):  
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Diesel Engines ◽  
Rapeseed Oil ◽  
High Speed ◽  
Fuel Injection ◽  
Experimental Studies ◽  
Fuel Injector ◽  
High Speed Diesel ◽  
Engine Type

The necessity of adapting diesel engines to work on vegetable oils is justified. The possibility of using rapeseed oil and its mixtures with petroleum diesel fuel as motor fuels is considered. Experimental studies of fuel injection of small high-speed diesel engine type MD-6 (1 Ch 8,0/7,5)when using diesel oil and rapeseed oil and computational studies of auto-tractor diesel engine type D-245.12 (1 ChN 11/12,5), working on blends of petroleum diesel fuel and rapeseed oil. When switching autotractor diesel engine from diesel fuel to rapeseed oil in the full-fuel mode, the mass cycle fuel supply increased by 12 %, and in the small-size high-speed diesel engine – by about 27 %. From the point of view of the flow of the working process of these diesel engines, changes in other parameters of the fuel injection process are less significant. Keywords diesel engine; petroleum diesel fuel; vegetable oil; rapeseed oil; high pressure fuel pump; fuel injector; sprayer

Experimental Studies of the Primary Zone Flow Field and Combustion Performance of a Triple Swirler Combustor

2005 ◽  
Author(s):  
Yunhui Peng ◽  
Quanhong Xu ◽  
Yuzhen Lin
Keyword(s):  
Flow Field ◽  
Experimental Studies ◽  
Fuel Injector ◽  
Lean Blowout ◽  
Combustion Performance ◽  
Primary Zone ◽  
Image Velocimetry ◽  
Aero Engine ◽  
Exit Temperature ◽  
Promising Solution

Improvement of the lean blowout limit and more uniform combustor exit temperature distribution are particularly desirable for future aero engine. A triple swirler combination plus an airblast fuel injector might be a promising solution. The design with the triple swirler plus the airblast fuel injector including design A and B was presented and investigated in this paper. Single rectangle sector module combustor was used in the experiment for lean blowout (LBO), and three cups rectangle sector combustor was used for pattern factor (PF) experiments. The LBO and PF experiment data were provided. The primary zone flow field was measured by PIV (Particle Image Velocimetry) under atmospheric pressure and temperature. The result showed that the design A was a promising design, and the primary jet played very important role for flow field of primary zone. The insight relation between flow field and combustion performance could be found out from this paper.

Modal Analysis of Breakup Mechanisms for a Liquid Jet in Crossflow

2021 ◽  
pp. 1-36
Author(s):  
Sheikh Salauddin ◽  
Wilmer Flores ◽  
Michelle Otero ◽  
Bernhard Stiehl ◽  
Kareem Ahmed
Keyword(s):  
Coherent Structures ◽  
Liquid Fuel ◽  
Hydrodynamic Instability ◽  
Aviation Industry ◽  
Dynamic Mode ◽  
Capillary Breakup ◽  
Breakup Mechanism ◽  
Jet In Crossflow ◽  
Fuel Jet ◽  
Primary Breakup

Abstract Liquid fuel jet in Crossflow (LJIC) is a vital atomization technique significant to the aviation industry. The hydrodynamic instability mechanisms that drive a primary breakup of a transverse jet are investigated using modal and traveling wavelength analysis. This study highlights the primary breakup mechanisms for aviation fuel Jet-A, utilizing a method that could be applied to any liquid fuel. Mathematical decomposition techniques known as POD (Proper Orthogonal Decomposition) and Robust MrDMD (Multi-Resolution Dynamic Mode Decomposition) are used together to identify dominant instability flow dynamics associated with the primary breakup mechanism. Implementation of the Robust MrDMD method deconstructs the nonlinear dynamical systems into multiresolution time-scaled components to capture the intermittent coherent structures. The Robust MrDMD, in conjunction with the POD method, is applied to data points taken across the entire spray breakup regimes: enhanced capillary breakup, bag breakup, multimode breakup, and shear breakup. The dominant frequencies of breakup mechanisms are extracted and identified. These coherent structures are classified with an associated time scale and Strouhal number. Three primary breakup mechanisms, namely ligament shedding, bag breakup, and shear breakup, were identified and associated with the four breakup regimes outlined above. Further investigation portrays these breakup mechanisms to occur in conjunction with each other in each breakup regime, excluding the low Weber number Enhanced Capillary Breakup regime. Spectral analysis of the Robust MrDMD modes' entire temporal window reveals that while multiple breakup mechanisms are convolved, there is a dominant breakup route for each breakup regime. An associated particular traveling wavelength analysis further investigates each breakup mechanism. Lastly, this study explores the effects of an increased momentum flux ratio on each breakup mechanism associated with a breakup regime.

scholarly journals Characterization and first results from LACIS-T: a moist-air wind tunnel to study aerosol–cloud–turbulence interactions

2020 ◽  
Vol 13 (4) ◽  
pp. 2015-2033 ◽  
Author(s):  
Dennis Niedermeier ◽  
Jens Voigtländer ◽  
Silvio Schmalfuß ◽  
Daniel Busch ◽  
Jörg Schumacher ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Spatial Scales ◽  
Experimental Studies ◽  
Field Measurements ◽  
Hygroscopic Growth ◽  
Moist Air ◽  
Aerosol Cloud ◽  
Cloud Microphysical Processes ◽  
First Results ◽  
Microphysical Processes

Abstract. The interactions between turbulence and cloud microphysical processes have been investigated primarily through numerical simulation and field measurements over the last 10 years. However, only in the laboratory we can be confident in our knowledge of initial and boundary conditions and are able to measure under statistically stationary and repeatable conditions. In the scope of this paper, we present a unique turbulent moist-air wind tunnel, called the Turbulent Leipzig Aerosol Cloud Interaction Simulator (LACIS-T) which has been developed at TROPOS in order to study cloud physical processes in general and interactions between turbulence and cloud microphysical processes in particular. The investigations take place under well-defined and reproducible turbulent and thermodynamic conditions covering the temperature range of warm, mixed-phase and cold clouds (25∘C>T>-40∘C). The continuous-flow design of the facility allows for the investigation of processes occurring on small temporal (up to a few seconds) and spatial scales (micrometer to meter scale) and with a Lagrangian perspective. The here-presented experimental studies using LACIS-T are accompanied and complemented by computational fluid dynamics (CFD) simulations which help us to design experiments as well as to interpret experimental results. In this paper, we will present the fundamental operating principle of LACIS-T, the numerical model, and results concerning the thermodynamic and flow conditions prevailing inside the wind tunnel, combining both characterization measurements and numerical simulations. Finally, the first results are depicted from deliquescence and hygroscopic growth as well as droplet activation and growth experiments. We observe clear indications of the effect of turbulence on the investigated microphysical processes.

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