This research aims to characterize emissions and flame stability for a low swirl burner (LSB) design in a full-scale combustor facility using high-hydrogen fuel blends. Previous research has shown LSBs can stabilize flames during lean combustion, reducing emissions. The full-scale combustor will test various hydrogen-methane mixtures at pressures and temperatures simulating gas turbine engines. High-speed imaging and emissions measurements will characterize flame shape and NOx, CO, CO2 levels for the LSB design across fuel mixtures. The goals are to better understand LSB combustion for applying alternative fuels to reduce environmental impacts of gas turbines.

1. Georgia Institute of Technology, Atlanta, Georgia
School of Aerospace Engineering
Ben T. Zinn Combustion Laboratory
Design of High-Pressure, Full-Scale Nozzle Test Facility
Michael Claugus, Ben Kingsley, Adam Kolojejchick-Kotch, Kelvin Murphy
Purpose
Background
• Typical aircraft gas turbine engines
currently use high swirl nozzles to
stabilize and hold the flame
• Low Swirl Burners use a diverging
flowfield instead of a highly swirling
flowfield to stabilize the flame
• Low swirl burners have been shown to
be able to operate at leaner
conditions, reducing emissions
Rig Design
• In conjunction, research in high-hydrogen fuels is being
conducted as a solution to reduce emissions from gas turbine
engines
• Previous research by others has shown that emission levels
can be influenced by fuel type and fuel mixtures, such as
using hydrogen-nitrogen or methane-hydrogen mixtures
• The research conducted will focus on emissions and flame
stability for a LSB utilizing high hydrogen fuel blends
• Characterize NOx, CO, CO2, and O2 emissions for a Low
Swirl Burner design in a full scale facility
• Characterize flame shape for a Low Swirl Burner design
in a full scale facility
Objectives
Critical Orifice Plate
• Choked flow (Mach=1)
• Stable conditions
• Able to calculate flow rate
(DP)
• Calculated using tables of
known OD, desired flow,
temp, and fuel mixture
Subcritical Orifice Plate
• More information is
needed to calculate
flow rate (DP, DT)
• Subsonic flow (M<1)
• Calculated using tables
of known OD, desired
flow, temp, and fuel
mixture
• Maintain b ratio
between 0.1 and 0.8 to
ensure accurate
measurements
Fuel Flow
Critical Orifice Subcritical Orifice Controller On/Off
Future Work
Fuel System
• There is increasing awareness of
the environmental impact of
land-based power generation
gas turbine engines
• Due to environmental concerns,
research on the reduction of
NOx, CO, and CO2 emissions is
increasing
• Previous research has shown that lean fuel mixtures reduce
emissions
• This has been shown to cause combustion instabilities,
flashback, and blowoff
• Fuel type also has impact on emissions
• Previous research has also shown that Low Swirl Burners (LSBs)
help to reduce instabilities, flashback and blowoff
• Designed to be adaptable so that multiple different nozzles can
be tested in the same pressure vessel
• Able to take temperature, pressure, acoustic and emissions
readings
• Four large quartz windows and quartz combustor liner for optical
access
• Exhaust cooled post combustor prior to exiting rig
Key Design Features:
• Choked inlet and exit to
isolate the combustor
acoustically
• Air mass flow rate of 2 kg/s
• Air preheated
• Maximum pressure of 6 atm
• 5 fuel blends available
Design Validation:
• Conducted finite element analysis of
pressure vessel using ANSYS to
determine stresses in vessel
• Conducted heat transfer analysis on
exhaust portion in pressure vessel to
ensure exhaust can withstand the
temperatures of the exhaust gases
• Five predetermined fuels to be used:
• Pure Hydrogen
• Pure Natural Gas
• Hydrogen/Natural Gas
• Hydrogen/Carbon Monoxide
• Hydrogen/Nitrogen
• Three fuel stages, each controlled independently
• Fuel pressure regulated by controller, limiting flow
• Fuel flow rates measured by both critical and subcritical
orifice plates to improve measurement accuracy
Flow Measurement
• Install designed fuel system
• Machine and assemble pressure vessel and internals
• Electrical set up
• Testing
• Final analysis
Control System
• Using a NI DAQ system to monitor
and control system
• Capable of monitoring 36
thermocouples
• Consists of 48 relays for regulating
fuel and air system
Mentor: Julia Lundrigan Advisor: Dr. Tim Lieuwen
Courtesy: Littlejohn, Cheng, Noble & Lieuwen 2010

2. • With the increasing awareness of the negative environmental impact of gas turbine engines and power plant emissions, research on
the reduction of NOx, CO, and CO2 emissions using novel combustor configurations and fuel mixtures is essential. One known
manner in which emissions from gas turbine engines and power plants can be reduced is be operating at lean conditions where the
equivalence ratio (ratio of fuel to air) is low and thus there is more air going through the combustor than is necessary to burn all of
the fuel. Lean combustion systems, however, are prone to combustion instabilities (acoustic and pressure fluctuations), flashback
(the flame propagates upstream), and blowoff (the flame leaves the combustor), which are all extremely detrimental to the system.
Additionally, these effects are worse with high H2 fuels which are most alternative fuels.
• One manner in which these challenges can be overcome is by utilizing low swirl burner (LSB) configurations. Typical aircraft gas
turbine engines currently use high swirl combustors to stabilize and hold the flame. However, previous research has shown that LSBs
can hold a flame during a large range of operating conditions, including very lean conditions. The ability to operate at these
extremely lean conditions ultimately assists with reduced emissions as well as reduced fuel consumption. In addition to utilizing
LSBs, investigations into alternative fuels is also being conducted as a solution to the challenges of greenhouse gas emissions from
gas turbine engines. Previous research by others has shown that emission levels can be influenced by fuel type and fuel mixtures,
such as using hydrogen-nitrogen or methane-hydrogen mixtures.
• The purpose of this research is to conduct high speed chemiluminescence flame imaging and NOx, CO, and CO2 emissions
measurements on novel low swirl burner designs for direct application in industrial gas turbines. For alternative fuels, the manner in
which the flame is stabilized using vortex breakdown in high swirl combustors can lead to increased flashback issues. High speed
chemiluminescence allows for direct observation and analysis of the flame. For these experiments specifically, broad spectrum and
narrow spectrum images will be taken. Narrow spectrum images will focus on the CH* band at 430 nm to ascertain the location of
the flame front; OH* will be used for high hydrogen tests. The research conducted will be on a full scale combustor using single
nozzle designs based on tests performed by another student in the Ben T. Zinn Combustion Laboratory. The combustor will be run at
high pressures and preheat temperatures to further simulate a real gas turbine engine environment. This research has direct
application to power gas turbines as well as indirect application to aircraft gas turbine engines.
• 1. To characterize NOx, CO, CO2, and O2 emissions for a Low Swirl Burner design in a full scale facility. To achieve this it will be
necessary to utilize multiple fuel mixtures to ensure the results represent a range of conditions the combustor would experience in
real world application. This will require testing using methane only, as well as multiple methane and hydrogen mixtures. In order to
simulate a full scale combustor environment, the combustor will be operated at 8atm with air preheated to 600°F and flow
velocities to match real world engine conditions.
• 2. To characterize flame shape for a Low Swirl Burner design in a full scale facility. as stated in the previous objective, to achieve this
it will be necessary to utilize multiple fuel mixtures to ensure the results represent a range of conditions the combustor would
experience in real world application. Additionally, a high resolution CCD camera will be used to take time-average broad spectrum
and narrow spectrum images. Narrow spectrum images will focus on the CH* band at 430 nm to ascertain the location of the flame
front. This will allow for further characterization of the LSB design.