scholarly journals A Method to Measure the Fuel Distribution and the Fuel Captured by V–Gutter Flameholder in High Speed Airstream

1985 ◽  
Author(s):  
Gu Shan-Jian ◽  
Yang Mao-Lin ◽  
Li Xiang-Yi
Keyword(s):  
Flow Rate ◽  
Experimental Error ◽  
High Speed ◽  
Fuel Flow Rate ◽  
Fuel Distribution ◽  
Fuel Flow ◽  
Sampling Condition ◽  
Detailed Determination

A method to measure the fuel distribution and the percentage of fuel flow rate captured by a V-gutter flameholder in a high speed airstream has been developed. The effects of configuration and size of the probe and temprature of the sample mixture in the probe on measurement have been investigated. The detailed determination of isokinetic sampling condition is described. The effects of V-gutter geometry on flowfield have been considered. The total experimental error is of the order ±5%.

scholarly journals Experimental Study of Thermo-Acoustic Instability Triggering in a Staged Liquid Fuel Combustor Using High-Speed OH-PLIF

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Antoine Renaud ◽  
Shigeru Tachibana ◽  
Shuta Arase ◽  
Takeshi Yokomori
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Pressure Fluctuations ◽  
Dynamic Mode ◽  
Frequency Change ◽  
Main Stage ◽  
Fuel Flow Rate ◽  
Time Frequency ◽  
Acoustic Instability ◽  
Fuel Flow

A staged injector developed by JAXA and fueled with kerosene is studied in a high-pressure combustion experiment. With a stable pilot fuel flow rate, the fuel flow rate in the main stage is progressively increased. A high-speed OH-planar laser-induced fluorescence (PLIF) system is used to record the flame motion at 10,000 fps. In the beginning of the recording, the flame behavior is dominated by relatively low-frequency rotation due to the swirling motion of the flow. These rotational motions then coexist with a thermo-acoustic instability around 475 Hz which increases the amplitude of the pressure fluctuations inside the chamber. Dynamic mode decomposition (DMD) analyses indicate that this instability is associated with a widening of the flame occurring when the pressure fluctuations are the highest, giving the instability a positive feedback. The instability frequency then abruptly switches to 500 Hz, while the mode shape remains the same. This frequency change is studied using time–frequency analysis to highlight a change in the feedback mechanism characterized by a modification of the time delay between pressure and heat release fluctuations.

scholarly journals Experimental Study of Thermo-Acoustic Instability Triggering in a Staged Liquid Fuel Combustor Using High-Speed OH-PLIF

2017 ◽  
Author(s):  
Antoine Renaud ◽  
Shigeru Tachibana ◽  
Shuta Arase ◽  
Takeshi Yokomori
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Pressure Fluctuations ◽  
Low Frequency ◽  
Frequency Change ◽  
Main Stage ◽  
Fuel Flow Rate ◽  
Acoustic Instability ◽  
Driving Mechanisms ◽  
Fuel Flow

A staged injector developed by JAXA and fueled with kerosene is studied in a high-pressure combustion experiment. With a stable pilot fuel flow rate, the fuel flow rate in the main stage is progressively increased. A high-speed OH-PLIF system is used to record the flame motion at 10,000 fps. In the beginning of the recording, POD modes shows that the flame behavior is dominated by relatively low-frequency rotation due to the swirling motion of the flow. These rotational motions then coexist with a thermo-acoustic instability around 475 Hz which increases the amplitude of the pressure fluctuations inside the chamber. DMD analyses indicate that this instability is associated with a widening of the flame occurring when the pressure fluctuations are the highest, giving the instability a positive feedback. The instability frequency then abruptly switches to 500 Hz while retaining the same driving mechanisms. Potential candidates for this frequency change are proposed.

Two-Dimensional Imaging of Soot Volume Fraction in Pulsed Diffusion Flames by Laser-Induced Incandescence

2006 ◽  
Author(s):  
H. Sapmaz ◽  
C. Ghenai
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Volume Fraction ◽  
Two Dimensional ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Laser Induced Incandescence ◽  
Pulsed Flames

Laser-Induced Incandescence (LII) is used in this study to measure soot volume fractions in steady and flickering ethylene diffusion flames burning at atmospheric pressure. Better understanding of flickering flame behavior also promises to improve understanding of turbulent combustion systems. A very-high-speed solenoid valve is used to force the fuel flow rate with frequencies between 10 Hz and 200 Hz with the same mean fuel flow rate of steady flame. Periodic flame flickers are captured by two-dimensional phase-locked emission and LII images for eight phases (0°–360°) covering each period. LII spectra scan for minimizing C2 swan band emission and broadband molecular florescence, a calibration procedure using extinction measurements, and corrections for laser extinction and LII signal trapping are carried out towards developing reliable LII for quantitative applications. A comparison between the steady and pulsed flames results and the effect of the oscillation frequency on soot volume fraction for the pulsed flames are presented.

Measurements of Soot Volume Fraction in Pulsed Diffusion Flames by Laser-Induced Incandescence

2006 ◽  
Author(s):  
H. Sapmaz ◽  
C. Ghenai
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Volume Fraction ◽  
Calibration Procedure ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Laser Induced Incandescence ◽  
Pulsed Flames

Laser-Induced Incandescence (LII) is used in this study to measure soot volume fractions in steady and flickering ethylene diffusion flames burning at atmospheric pressure. Better understanding of flickering flame behavior also promises to improve understanding of turbulent combustion systems. A very-high-speed solenoid valve is used to force the fuel flow rate with frequencies between 10 Hz and 200 Hz with the same mean fuel flow rate of steady flame. Periodic flame flickers are captured by two-dimensional phase-locked emission and LII images for eight phases (0° - 360°) covering each period. LII spectra scan for minimizing C2 swan band emission and broadband molecular florescence, a calibration procedure using extinction measurements, and corrections for laser extinction and LII signal trapping are carried out towards developing reliable LII for quantitative applications. A comparison between the steady and pulsed flames results and the effect of the oscillation frequency on soot volume fraction for the pulsed flames are presented.

Determination of the Instantaneous Fuel Flow Rate Out of a Fuel Nozzle

2009 ◽  
Vol 132 (2) ◽  
Author(s):  
Tongxun Yi ◽  
Domenic A. Santavicca
Keyword(s):  
Acoustic Wave ◽  
Flow Rate ◽  
Acoustic Velocity ◽  
Fuel Injector ◽  
Pressure Pulsations ◽  
Fuel Flow Rate ◽  
Flow Rates ◽  
Fuel Flow ◽  
Fuel Nozzle

Reported is a practical method for accurate and fast determination of the instantaneous fuel flow rate out of a fuel injector. Both gaseous and liquid fuels are considered. Unsteady fuel flow rates introduced into a combustor can be caused by both self-excited pressure pulsations and fuel modulations. During combustion instability, the air flow rate into a combustor also varies in response to pressure pulsations. Accurate determination of the instantaneous fuel and air flow rates is important for both modeling and control of combustion instability. The developed method is based on the acoustic wave theory and pressure measurements at two locations upstream of a fuel injector. This method bypasses the complexities and nonlinearities of fuel actuators and fuel nozzles, and works for systems with slow-time-varying characteristics. Acoustic impedance of a gaseous fuel nozzle is found to be a function of multivariables, including the forcing frequency, the acoustic oscillation intensity, and the mean fuel flow rate. Thus, it is not an intrinsic property of the fuel injector alone. In the present study, sharp tubing bending with almost zero radii is found to have minimal effects on the distribution of 1D acoustic wave. This is probably because vortex shedding and recirculation at tubing corners do not alter the globally 1D characteristics of acoustic wave distribution. Different from the traditional two-microphone method, which determines the acoustic velocity at the middle locations of the two microphones, the present method allows the acoustic velocity, the acoustic mass flux, and the specific acoustic impedance to be determined along the fuel tubing or an air pipe.

Dynamic Simulation of a HRSG System for a Given Start-Up/Shut Down Curve

2011 ◽  
Author(s):  
Hun Cha ◽  
Yoo Seok Song ◽  
Kyu Jong Kim ◽  
Jung Rae Kim ◽  
Sung Min KIM
Keyword(s):  
Dynamic Analysis ◽  
Gas Turbine ◽  
Flow Rate ◽  
Exhaust Gas ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Start Up ◽  
Gas Turbine Exhaust ◽  
Main Steam ◽  
Duct Burner

An inappropriate design of HRSG (Heat Recovery Steam Generator) may lead to mechanical problems including the fatigue failure caused by rapid load change such as operating trip, start-up or shut down. The performance of HRSG with dynamic analysis should be investigated in case of start-up or shutdown. In this study, dynamic analysis for the HRSG system was carried out by commercial software. The HRSG system was modeled with HP, IP, LP evaporator, duct burner, superheater, reheater and economizer. The main variables for the analysis were the temperature and mass flow rate from gas turbine and fuel flow rate of duct burner for given start-up (cold/warm/hot) and shutdown curve. The results showed that the exhaust gas condition of gas turbine and fuel flow rate of duct burner were main factors controlling the performance of HRSG such as flow rate and temperature of main steam from final superheater and pressure of HP drum. The time delay at the change of steam temperature between gas turbine exhaust gas and HP steam was within 2 minutes at any analysis cases.

Model Analysis of Syngas Combustion and Emissions for a Micro Gas Turbine

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Chi-Rong Liu ◽  
Hsin-Yi Shih
Keyword(s):  
Gas Turbine ◽  
Flow Rate ◽  
Heat Input ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Fuel Flow Rate ◽  
Micro Gas Turbine ◽  
Fuel Flow ◽  
Temperature Distributions ◽  
Flame Structures

The purpose of this study is to investigate the combustion and emission characteristics of syngas fuels applied in a micro gas turbine, which is originally designed for a natural gas fired engine. The computation results were conducted by a numerical model, which consists of the three-dimension compressible k–ε model for turbulent flow and PPDF (presumed probability density function) model for combustion process. As the syngas is substituted for methane, the fuel flow rate and the total heat input to the combustor from the methane/syngas blended fuels are varied with syngas compositions and syngas substitution percentages. The computed results presented the syngas substitution effects on the combustion and emission characteristics at different syngas percentages (up to 90%) for three typical syngas compositions and the conditions where syngas applied at fixed fuel flow rate and at fixed heat input were examined. Results showed the flame structures varied with different syngas substitution percentages. The high temperature regions were dense and concentrated on the core of the primary zone for H2-rich syngas, and then shifted to the sides of the combustor when syngas percentages were high. The NOx emissions decreased with increasing syngas percentages, but NOx emissions are higher at higher hydrogen content at the same syngas percentage. The CO2 emissions decreased for 10% syngas substitution, but then increased as syngas percentage increased. Only using H2-rich syngas could produce less carbon dioxide. The detailed flame structures, temperature distributions, and gas emissions of the combustor were presented and compared. The exit temperature distributions and pattern factor (PF) were also discussed. Before syngas fuels are utilized as an alternative fuel for the micro gas turbine, further experimental testing is needed as the modeling results provide a guidance for the improved designs of the combustor.

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