Experimental and Numerical Spray Characterization of a Gas Turbine Fuel Atomizer in Cross Flow

2002 ◽  
Author(s):  
F. A. Tap ◽  
A. J. Dean ◽  
J. P. Van Buijtenen
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Droplet Size ◽  
Cross Flow ◽  
Field Measurements ◽  
Fuel Injector ◽  
Ambient Conditions ◽  
Air Stream ◽  
Break Up

An experimental and numerical characterization of a macrolaminate pressure atomizer, placed perpendicularly to a high-velocity, turbulent air stream, is presented in this work. The purpose of the study was to compare detailed spray measurements with computations using a commercial CFD code. This study was part of the development of the premixing section of a midsize gas turbine, redesigned to meet low emissions and dual fuel market requirements. First, the spray characteristics were determined by injecting into a quiescent environment at ambient conditions. This data provided input for CFD calculations. Then the fuel injector was placed in a test section, at ambient conditions as well, that simulated the cross flow position of the atomizer in the prototype combustor. Droplet size and velocity were measured downstream of the injector nozzle, using a one-dimensional Phase Doppler Particle Analyzer. Measurements were done in two measuring planes. Flow field measurements were made to establish a common base for the computations. 2D computations were made of these experiments, using a k-ε turbulence model. The droplet trajectories were calculated with a Lagrangian ‘random walk’ technique, including drop break-up. The computed droplet size and velocity show agreement with the measurements. Drop break-up was also well represented by the model. The computed dispersion of the injected mass is not in agreement with the measured profile. This discrepancy in droplet dispersion is possibly due to high turbulence levels in the flow field, which were not well captured in the model.

Simulation of Airflow and Fuel Spray Through an Axial Swirler for Gas Turbine Applications

2008 ◽  
Author(s):  
Joshua E. Kempenaar ◽  
Kim A. Shollenberger ◽  
Gareth W. Oskam
Keyword(s):  
Gas Turbine ◽  
Cfd Simulation ◽  
Cross Flow ◽  
Fuel Spray ◽  
Fuel Injector ◽  
Discrete Phase Model ◽  
Flow Area ◽  
Jet In Cross Flow ◽  
Discrete Phase ◽  
Break Up

A computational fluid dynamics (CFD) simulation of the effects of an upstream blockage on the fuel spray and airflow through an axial swirler in an experimental gas turbine fuel injector has been conducted. Blockage was varied by means of varying the inside diameter of a restriction upstream of the entrance to the axial swirler. Fuel is injected as a jet in cross-flow through fuel nozzles located in axial swirler vanes. Fuel spray was modeled in the commercial CFD code Fluent 6.3.26 using the Lagrangian approach with the built-in Discrete Phase Model (DPM). Results are given for the TAB, Wave, and KH-RT break-up models. Preliminary simulations with the TAB break-up model were performed for a simple axisymmetric jet and compared to experimental results before simulating the axial swirler geometry. The axial swirler simulations predict that spray dispersion decreases and droplet size increases as the flow area of the blocker ring increases.

scholarly journals Transient Three-Dimensional Flow Field Measurements by Means of 3D µPTV in Drying Poly(Vinyl Acetate)-Methanol Thin Films Subject to Short-Scale Marangoni Instabilities

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1223
Author(s):  
Max Tönsmann ◽  
Philip Scharfer ◽  
Wilhelm Schabel
Keyword(s):  
Flow Field ◽  
Vinyl Acetate ◽  
Three Dimensional ◽  
Field Measurements ◽  
Initial Assessment ◽  
Ambient Conditions ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Short Scale ◽  
Dry Film

Convective Marangoni instabilities in drying polymer films may induce surface deformations, which persist in the dry film, deteriorating product performance. While theoretic stability analyses are abundantly available, experimental data are scarce. We report transient three-dimensional flow field measurements in thin poly(vinyl acetate)-methanol films, drying under ambient conditions with several films exhibiting short-scale Marangoni convection cells. An initial assessment of the upper limit of thermal and solutal Marangoni numbers reveals that the solutal effect is likely to be the dominant cause for the observed instabilities.

Computational Design and Experimental Evaluation of Using a Leading Edge Fillet on a Gas Turbine Vane

2001 ◽  
Author(s):  
G. A. Zess ◽  
K. A. Thole
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Pressure Gradient ◽  
Gas Turbine ◽  
Total Pressure ◽  
Guide Vane ◽  
Leading Edge ◽  
Field Measurements ◽  
Computational Design ◽  
Horseshoe Vortex

With the desire for increased power output for a gas turbine engine comes the continual push to achieve higher turbine inlet temperatures. Higher temperatures result in large thermal and mechanical stresses particularly along the nozzle guide vane. One critical region along a vane is the leading edge-endwall juncture. Based on the assumption that the approaching flow to this juncture is similar to a two-dimensional boundary layer, previous studies have shown that a horseshoe vortex forms. This vortex forms because of a radial total pressure gradient from the approaching boundary layer. This paper documents the computational design and experimental validation of a fillet placed at the leading edge-endwall juncture of a guide vane to eliminate the horseshoe vortex. The fillet design effectively accelerated the incoming boundary layer thereby mitigating the effect of the total pressure gradient. To verify the CFD studies used to design the leading edge fillet, flow field measurements were performed in a large-scale, linear, vane cascade. The flow field measurements were performed with a laser Doppler velocimeter in four planes orientated orthogonal to the vane. Good agreement between the CFD predictions and the experimental measurements verified the effectiveness of the leading edge fillet at eliminating the horseshoe vortex. The flowfield results showed that the turbulent kinetic energy levels were significantly reduced in the endwall region because of the absence of the unsteady horseshoe vortex.

An Experiment Study of Wall Slot Jets Pertinent to Trailing Edge Cooling of Turbine Blades

2010 ◽  
Author(s):  
Zifeng Yang ◽  
Anand Gopa Kumar ◽  
Hirofumi Igarashi ◽  
Hui Hu
Keyword(s):  
Flow Field ◽  
Turbine Blades ◽  
Flow Characteristics ◽  
Field Measurements ◽  
Main Stream ◽  
Wall Jet ◽  
Ambient Conditions ◽  
Trailing Edge ◽  
Jet Streams ◽  
Cooling Effectiveness

An experimental study was conducted to quantify the flow characteristics of wall jets pertinent to trailing edge cooling of turbine blades. A high-resolution stereoscopic PIV system was used to conduct detailed flow field measurements to quantitatively visualize the evolution of the unsteady vortex and turbulent flow structures in cooling wall jet streams and to quantify the dynamic mixing process between the cooling wall jet streams and the main stream flows. The detailed flow field measurements are correlated with the adiabatic cooling effectiveness maps measured by using pressure sensitive paint (PSP) technique to elucidate underlying physics in order to improve cooling effectiveness to protect the critical portions of turbine blades from the harsh ambient conditions.

URANS Simulation of an Appended Hull During Steady Turn With Propeller Represented by an Actuator Disk Model

2011 ◽  
Author(s):  
Charles M. Dai ◽  
Ronald W. Miller
Keyword(s):  
Flow Field ◽  
Cross Flow ◽  
Field Measurements ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
Complex Flow ◽  
Ship Maneuvering ◽  
Disk Model ◽  
Actuator Disk ◽  
Propeller Wake

This paper reports on the comparison between computational simulations and experimental measurements of a surface vessel in steady turning conditions. The primary purpose of these efforts is to support the development of physics-based high fidelity maneuvering simulation tools by providing accurate and reliable hydrodynamic data with relevance to maneuvering performances. Reynolds Averaged Unsteady Navier Stokes Solver (URANS): CFDSHIPIOWA was used to perform simulations for validation purposes and for better understanding of the fundamental flow physics of a hull under maneuvering conditions. The Propeller effects were simulated using the actuator disk model included in CFDShip-Iowa. The actuator disk model prescribes a circumferential averaged body force with axial and tangential components. No propeller generated side forces are accounted for in the model. This paper examines the effects of actuator disk model on the overall fidelity of a RANS based ship maneuvering simulations. Both experiments and simulations provide physical insights into the complex flow interactions between the hull and various appendages, the rudders and the propellers. The experimental effort consists of flow field measurements using Stereo Particle-Image Velocimetry (SPIV) in the stern region of the model and force and moment measurements on the whole ship and on ship components such as the bilge keels, the rudders, and the propellers. Comparisons between simulations and experimental measurements were made for velocity distributions at different transverse planes along the ship axis and different forces components for hull, appendages and rudders. The actuator disk model does not predict any propeller generated side forces in the code and they need to be taken into account when comparing hull and appendages generated side forces in the simulations. The simulations were compared with experimental results and they both demonstrate the cross flow effect on the transverse forces and the propeller slip streams generated by the propellers during steady turning conditions. The hull forces (include hull, bilge keels, skeg, shafting and strut) predictions were better for large turning circle case as compared with smaller turning circle. Despite flow field simulations appear to capture gross flow features qualitatively; detailed examinations of flow distributions reveal discrepancies in predictions of propeller wake locations and secondary flow structures. The qualitative comparisons for the rudders forces also reveal large discrepancies and it was shown that the primary cause of discrepancies is due to poor predictions of velocity inflow at the rudder plane.

Advanced Multi-Cup Fuel Injector Technology for Environmentally Responsible Aviation Gas Turbine Engines

2015 ◽  
Author(s):  
Erlendur Steinthorsson ◽  
Adel Mansour ◽  
Brian Hollon ◽  
Michael Teter ◽  
Clarence Chang
Keyword(s):  
Gas Turbine ◽  
Direct Injection ◽  
Pressure Ratio ◽  
Test Facility ◽  
Turbine Engines ◽  
Practical Implementation ◽  
Gas Turbine Engines ◽  
Fuel Injector ◽  
Ambient Conditions ◽  
Environmentally Responsible

Participating in NASA’s Environmentally Responsible Aviation (ERA) Project, Parker Hannifin built and tested multipoint Lean Direct Injection (LDI) fuel injectors designed for NASA’s N+2 55:1 Overall Pressure-Ratio (OPR) gas turbine engine cycles. The injectors are based on Parker’s earlier three-zone injector (3ZI) which was conceived to enable practical implementation of multipoint LDI schemes in conventional aviation gas turbine engines. The new injectors offer significant aerodynamic design flexibility, excellent thermal performance, and scalability to various engine sizes. The injectors built for this project contain 15 injection points and incorporate staging to enable operation at low power conditions. Ignition and flame stability were demonstrated at ambient conditions with ignition air pressure drop as low as 0.3% and fuel-to-air ratio (FAR) as low as 0.011. Lean Blowout (LBO) occurred at FAR as low as 0.005 with air at 460 K and atmospheric pressure. A high pressure combustion testing campaign was conducted in the CE-5 test facility at NASA Glenn Research Center at pressures up to 250 psi and combustor exit temperatures up to 2,033 K (3,200 °F). The tests demonstrated estimated LTO cycle emissions that are about 30% of CAEP/6 for a reference 60,000 lbf thrust, 54.8-OPR engine. This paper presents some details of the injector design along with results from ignition, LBO and emissions testing.

Flow Field Derived Equivalent Reactor Networks for Accurate Chemistry Simulation in Gas Turbine Combustors

2009 ◽  
Author(s):  
Scott A. Drennan ◽  
Chen-Pang Chou ◽  
Anthony F. Shelburn ◽  
Devin W. Hodgson ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Flame Structure ◽  
Cost Effective ◽  
Fuel Injector ◽  
Accurate Analysis ◽  
Detailed Chemistry ◽  
Reactor Networks ◽  
Detailed Kinetics ◽  
Time Required

A method has been developed in which the flow field predicted by Computational Fluid Dynamics (CFD) is automatically condensed into an Equivalent Reactor Network (ERN), composed of well stirred reactors, allowing rapid and accurate analysis of emissions. This paper presents the effectiveness of utilizing an ERN that is a direct abstraction of the computational flow field for combustion analysis. The CFD results are divided into reactors using various filters on flow-field variables to construct an ERN that represents the 3-D combustor flow field and flame structure. Detailed kinetics can then be used in ERN simulations to analyze effects of fuel composition and operating condition on emissions. The technique is applied to a commercial industrial gas turbine combustor fuel injector and compared against experimental emissions results. Sensitivity of emissions predictions to different parameters in the network extraction is also presented. Parameter variations in fuel flow rate are applied to the ERN to obtain relative impacts of fuel-air ratio on the emissions of NOx without requiring new CFD solutions. This automatic approach has been found to reduce the time required to construct and analyze flow field derived ERNs with detailed chemistry by 90%. A local calculation of Damko¨hler number, important for stability analysis, is also presented. This calculation also uses abstracted information from the CFD flow field and detailed-kinetics simulations for more accurate, cost-effective analysis.

Investigation of Flow Characteristics in a Combustor With Opposed Jets

2018 ◽  
Author(s):  
Yongbin Ji ◽  
Bing Ge ◽  
Shusheng Zang
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Momentum Flux ◽  
Flow Characteristics ◽  
Cross Flow ◽  
Flux Ratio ◽  
Main Flow ◽  
3D Flow ◽  
Momentum Flux Ratio ◽  
High Efficient

Jet-in-cross flow (JICF) has been investigated broadly because of its wide engineering application, for example in the gas turbine field, film cooling on the turbine vanes and blades, primary and dilution jets in the combustors and so on. In the gas turbine combustors, the main flow is generated by the swirlers to stabilize the flame, which induces complicated 3D flow characteristics. Different from uniform main flow, swirling cross flow has a strong tangential velocity component, which will deflect the jets in the circumferential direction as well as in the streamwise direction. So, the degradation behavior of the jets is more complex than that in the uniform cross flow. This paper presents PIV measurement of the flow field inside of a three-nozzle annular combustor with opposed quenching jets on the liner walls. Dry ice as a newly proposed flow tracer was proposed and tried. The momentum flux ratio and jet holes configuration are studied to evaluate their effects on the primary recirculation zone, downstream flow field. Finally, numerical simulation was also performed to reveal 3D flow characteristics as well as turbulent kinetic energy generation. The results show that momentum flux ratio has a dominant influence on flow characteristics in the combustor. Getting better understanding of jets behavior in the swirling cross flow helps optimization design of quenching or dilution holes geometry and arrangement for the gas turbine combustor, which turns to be very beneficial to the low-emission and high efficient combustor development.

The Impact of Representative Aerodynamic Flow Fields on Liquid Fuel Atomisation in Modern Gas Turbine Fuel Injectors

2014 ◽  
Author(s):  
A. G. Barker ◽  
J. F. Carrotte
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Liquid Fuel ◽  
Swirling Flow ◽  
Subsequent Development ◽  
Potential Effect ◽  
Far Field ◽  
Fuel Injector ◽  
Swirl Vane ◽  
The Impact

In modern gas turbine engines swirl is typically imparted to the airflow as it enters the region of heat release to stabilize the flame. This swirling airstream is often highly turbulent and contains non-uniformities such as swirl vane wakes. However, it is within this environment that fuel atomization takes place. This paper is concerned with the potential effect of these airstream characteristics on the atomization process. Such a flow field is difficult to capture within simplified geometries and so measurements have been made within, and downstream of, injector representative geometries. This is experimentally challenging and required the application of a variety of techniques. The geometry considered is thought typical of an air-blast style injector, as may be used within current or future applications, whereby liquid fuel is introduced onto a pre-filming surface over which an airstream passes. Data is presented which characterizes the atomizing airstream presented to the pre-filming region. This includes significant flow field non-uniformities and turbulence characteristics that are mainly associated with the swirling flow along with the vanes used to impart this swirl. The subsequent development of these aerodynamic features over the pre-filming surface is also captured with, for example, swirl vane wakes being evident through the injector passage and into the downstream flow field. It is argued these characteristics will be common to many injector designs. Measurements with and without fuel indicate the effect of the liquid film, on the non-dimensional aerodynamic flow field upstream of the pre-filming region, is minimal. However, the amount of airflow passing through the pre-filming passage is affected. In addition to characterization of the airstream, its impact on the liquid fuel film and its development along the pre-filming surface is visualized. Furthermore, PDA measurements downstream of the fuel injector (i.e. the injector ‘far-field) are presented and the observed spray characteristics spatially correlated with the upstream aerodynamic atomizing flow field. Hence for the first time a series of experimental techniques have been used to capture and correlate both near and far field atomization characteristics within an engine representative aerodynamic flow field.

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