Computational and Experimental Analysis of a Compact Combustor Integrated into a JetCat P90 RXi

2021 ◽  
Author(s):  
Daniel Holobeny ◽  
Brian T. Bohan ◽  
Marc D. Polanka
Keyword(s):  
Bluff Body ◽  
Flame Stabilization ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Turbine Engine ◽  
Pressure Losses ◽  
Primary Zone ◽  
Sustained Operation ◽  
Mass Flow Rates ◽  
Stable Flame

Abstract Ultra Compact Combustors (UCC) look to reduce the overall combustor length and weight in modern gas turbine engines. Previously, a UCC achieved self-sustained operation at sub-idle speeds in a JetCat P90 RXi turbine engine with a length savings of 33% relative to the stock combustor. However, that combustor experienced flameout as reactions were pushed out of the primary zone before achieving mass flow rates at the engine's idle condition. A new combustor that utilized a bluff body flame stabilization with a larger combustor volume looked to keep reactions in the primary zone within the same axial dimensions. This design was investigated computationally for generalized flow patterns, pressure losses, exit temperature profiles, and reaction distributions at three engine power conditions. The computational results showed the validity of this new Ultra Compact Combustor, with a turbine inlet temperature of 1080 K and a pattern factor of 0.67 at the cruise condition. The combustor was then built and tested in the JetCat P90 RXi with rotating turbomachinery and gaseous propane fuel. The combustor maintained a stable flame from ignition through the 36,000 RPM idle condition. The engine ran self-sustained from 25,000 to 36,000 RPM with an average exit gas temperature of 980 K, which is comparable to the stock engine.

Experimental Study on Pressure Losses in Porous Materials

2018 ◽  
Author(s):  
Giacomo Fantozzi ◽  
Mats Kinell ◽  
Sara Rabal Carrera ◽  
Jenny Nilsson ◽  
Yves Kuesters
Keyword(s):  
Discharge Coefficient ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Turbine Engine ◽  
Geometrical Properties ◽  
Pressure Losses ◽  
Technological Advances ◽  
Pore Radius Distribution ◽  
Engine Components ◽  
Test Objects

Recent technological advances in the field of additive manufacturing have made possible to manufacture turbine engine components characterized by controlled permeability in desired areas. These have shown great potential in cooling application such as convective cooling and transpiration cooling and may in the future contribute to an increase of the turbine inlet temperature. This study investigates the effects of the pressure ratio, the thickness of the porous material and the hatch distance used during manufacturing on the discharge coefficient. Moreover, two different porous structures were tested and in total 70 test objects were investigated. Using a scanning electron microscope, it is shown that the porosity and pore radius distribution, which are a result from the used laser power, laser speed and hatch distance during manufacturing, will characterize the pressure losses in the porous sample. Furthermore, the discharge coefficient increases with increasing pressure ratio, while it decreases with increasing thickness to diameter ratio. The obtained experimental data was used to develop a correlation for the discharge coefficient as a function of the geometrical properties and the pressure ratio.

Effect of Air Pressure and Gutter Angle on Flame Stability and DeZubay Number for Methane-Air Combustion

2017 ◽  
Vol 34 (1) ◽  
Author(s):  
S. Boopathi ◽  
P. Maran
Keyword(s):  
High Speed ◽  
Pressure Range ◽  
Bluff Body ◽  
Apex Angle ◽  
Flame Stabilization ◽  
Air Pressure ◽  
Flame Stability ◽  
Stability Chart ◽  
Stable Flame

AbstractThe combustion at high speed reactants requires a flame holding characteristics to sustain the flame in the afterburner. The flame holding characteristics of the combustor is carried out by the bluff-body stabilizers. The range of conditions of parameters influencing the flame stabilization is to be identified and the effects on the flame sustainability have to be investigated. DeZubay used the concept of DeZubay number and flame stability envelope to determine the stabilization and blowout range. In the present work, the effect of air pressure and the angle of apex of the V-gutter on flame stabilization and blowout mechanism have been experimentally investigated for six different apex angles and four different air pressure conditions. The value of DeZubay number at each condition has been calculated and verified with DeZubay stability chart for flame stabilization. The results show that stable flame is obtained for the entire pressure range when the apex angle of the V gutter is in 60° and 90°.

scholarly journals Experimental investigation of distance between v-gutters on flame stabilization and NOx emissions

2019 ◽  
Vol 23 (5 Part B) ◽  
pp. 2971-2981 ◽  
Author(s):  
Dias Umyshev ◽  
Abay Dostiyarov ◽  
Andrey Kibarin ◽  
Galya Tyutebayeva ◽  
Gaziza Katranova ◽  
...  
Keyword(s):  
Bluff Body ◽  
Flame Stabilization ◽  
Temperature Fields ◽  
Flame Stability ◽  
Bluff Bodies ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Inlet Velocity ◽  
Exhaust Gas Temperature

Blow-off performance and NOx emissions of the propane and air mixture in a rectangular combustion chamber with bluff bodies were investigated experimentally and numerically. The effects of distance between bluff bodies on NOx emissions, the blow-off limit, and exhaust gas temperature were examined. It was observed that NOx emissions are highly dependent on distance between V-gutters. The re-circulation zone behind the bluff body expands in width based on the decrease of distance between V-gutters, and expands in length with the increase of inlet velocity. The temperature fields behind the bluff body show a similar change, the temperature behind the bluff body reaches its highest when the distance between V-gutters reaches 20 mm, meaning it has better flame stability. The blow-off limit is significantly improved with the decrease of distance between V-gutters. The blow-off limit is greatly improved by reducing the distance between the V-gutters. Maximum blow-off limit of 0.11 is reached in the case of 20 mm, compared with 0.16 at 50 mm at a speed of 10 m/s.

scholarly journals Development of the AGT101 Regenerator Seals

1987 ◽  
Author(s):  
C. A. Fucinari ◽  
J. K. Vallance ◽  
C. J. Rahnke
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Dynamic Test ◽  
Development Program ◽  
Analytical Techniques ◽  
Gas Turbine Engine ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Turbine Engine ◽  
Seal Design

The design and development of the regenerator seals used in the AGT101 gas turbine engine are described in this paper. The all ceramic AGT101 gas turbine engine was designed for 100 hp at 5:1 pressure ratio with 2500F (1371C) turbine inlet temperature. Six distinct phases of seal design were investigated experimentally and analytically to develop the final design. Static and dynamic test rig results obtained during the seal development program are presented. In addition, analytical techniques are described. The program objectives of reduced seal leakage, without additional diaphragm cooling, to 3.6% of total engine airflow and higher seal operating temperature resulting from the 2000F (1093C) inlet exhaust gas temperature were met.

Acoustic Sensitivities of Lean-Premixed Fuel Injectors in a Single Nozzle Rig

1999 ◽  
Vol 121 (3) ◽  
pp. 429-436 ◽  
Author(s):  
D. W. Kendrick ◽  
T. J. Anderson ◽  
W. A. Sowa ◽  
T. S. Snyder
Keyword(s):  
Mach Number ◽  
Bluff Body ◽  
Dynamical Behavior ◽  
Flame Stabilization ◽  
Acoustic Characteristics ◽  
Turbine Engine ◽  
Fuel Injectors ◽  
Acoustic Coupling ◽  
Lean Premixed ◽  
Exit Mach Number

An experimental and numerical investigation into the attenuation of combustion induced pressure oscillations in a single nozzle rig was undertaken at the United Technologies Research Center. Results from these investigations indicated a high combustor exit Mach number, similar to that used in a gas turbine engine, was required to correctly simulate the combustor dynamics and evaluate acoustic characteristics of lean premixed fuel injectors. Comparisons made between aerodynamically stabilized and bluff-body stabilized nozzles and the use of premixed and diffusion pilots showed that small levels of diffusion piloting behind a bluff-body yielded the best acoustic/emission performance. Their success is due to increased flame stabilization (superior anchoring ability), which reduced flame motion and thermal/acoustic coupling. For cases where diffusion piloting was not present, both designs exhibited similar dynamical behavior. Increases in the combustor exit Mach number and reductions in the inlet air temperature were shown to degrade acoustic performance of both nozzle designs. The bluff-body configuration with small levels of diffusion piloting, however, was found to be less sensitive to these changes when compared to its aerodynamic counterpart.

Dynamics of Non-Premixed Bluff Body-Stabilized Flames in Heated Air Flow

2010 ◽  
Author(s):  
Caleb Cross ◽  
Aimee Fricker ◽  
Dmitriy Shcherbik ◽  
Eugene Lubarsky ◽  
Ben T. Zinn ◽  
...  
Keyword(s):  
Heat Release ◽  
Vortex Shedding ◽  
High Speed ◽  
Bluff Body ◽  
Combustion Process ◽  
Flame Stabilization ◽  
Inlet Temperature ◽  
Fuel Injectors ◽  
Flame Holder ◽  
Process Heat

This paper describes a study of the fundamental flame dynamic processes that control bluff body-stabilized combustion of liquid fuel with low dilatation. Specifically, flame oscillations due to asymmetric vortex shedding downstream of a bluff body (i.e., the Be´nard/von-Ka´rma´n vortex street) were characterized in an effort to identify the fundamental processes that most affect the intensity of these oscillations. For this purpose, the spatial and temporal distributions of the combustion process heat release were characterized over a range of inlet velocities, temperatures, and overall fuel-air ratios in a single flame holder combustion channel with full optical access to the flame. A stream of hot preheated air was supplied to the bluff body using a preburner, and Jet-A fuel was injected across the heated gas stream from discrete fuel injectors integrated within the bluff body. The relative amplitudes, frequencies, and phase of the sinusoidal flame oscillations were characterized by Fourier analysis of high-speed movies of the flame. The amplitudes of the flame oscillations were generally found to increase with global equivalence ratio, reaching a maximum just before rich blowout. Comparison of the flame dynamics to the time-averaged spatial heat release distribution revealed that the intensity of the vortex shedding decreased as a larger fraction of the combustion process heat release occurred in the shear layers surrounding the recirculation zone of the bluff body. Furthermore, a complete transition of the vortex shedding and consequent flame stabilization from asymmetric to symmetric modes was clearly observed when the inlet temperature was reduced from 850°C to 400°C (and hence, significantly increasing the flame dilatation ratio from Tb/Tu ∼ 2.3 to 3.7).

Performance Comparison of Aero-Engine Thrust Augmentors Stabilized by Bluff Body Flame Holders and a Flame-Holder-Less Concept

2011 ◽  
Author(s):  
Armin Tammer ◽  
John T. Cutright ◽  
Yedidia Neumeier ◽  
Ben T. Zinn
Keyword(s):  
Thermal Efficiency ◽  
Bluff Body ◽  
Weight Ratio ◽  
Performance Comparison ◽  
Flame Stabilization ◽  
Pressure Losses ◽  
Stable Combustion ◽  
Flame Holder ◽  
Engine Thrust ◽  
Flight Range

This study investigates the performance benefits of a flame-holder-less flame stabilization concept for thrust augmentors compared to the common flame holder design. The concept proposes to burn a small portion of the augmentor fuel in a rich mixture with air bled from the compressor to produce a highly reactive partially oxidized fuel-air mixture (POx). The POx mixture is injected into the turbine exit flow to enhance combustion kinetics in order to achieve stable combustion in the augmentor. Thermal efficiency during wet and dry operation is compared, taking into account both the pressure losses due to the flame holders and the reduction of core air for the flame-holder-less concept. Furthermore, the thrust-to-weight ratio and the corresponding flight range have been investigated with respect to the system weight and the induced losses. It was found that the thermal efficiency during dry operation is significantly increased when the pressure losses of the flame holders are eliminated. During wet operation, it was calculated that a flame holder system with only 2% total pressure loss of the flow would operate at the same thermal efficiency as the flame-holder-less concept when 3% air is bled from the compressor. If, for an engine operating at these conditions, the flame-holder-less system could maintain stable combustion using less than 3% bleed air, it would increase the thermal efficiency of that engine during wet operation. The results also suggest that a flame-holder-less system is lighter weight and has the potential to increase engine thrust-to-weight ratio and extend flight range when compared to a flame holder system designed to operate at the same overall engine thermal efficiency.

scholarly journals Performance and Exhaust Emissions of a Gas-Turbine Engine Fueled with Biojet/Jet A-1 Blends for the Development of Aviation Biofuel in Tropical Regions

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6570
Author(s):  
Iman K. Reksowardojo ◽  
Long H. Duong ◽  
Rais Zain ◽  
Firman Hartono ◽  
Septhian Marno ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Alternative Fuels ◽  
Coconut Oil ◽  
Gas Turbine Engine ◽  
Inlet Temperature ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Tropical Regions ◽  
Turbine Engine ◽  
Performance And Emissions

Biofuels as alternative fuels in today’s world are becoming increasingly important for the reduction of greenhouse gases. Here, we present and evaluate the potential of a new alternative fuel based on the conversion of medium-chain fatty acids to biojet (MBJ), which was produced from coconut oil using hydrotreated processes. MBJ is produced by using both deoxygenation and isomerization processes. Several blends of this type of biojet fuel with Jet A-1 were run in a gas-turbine engine (Rover 1S/60, ROTAX LTD., London, England) for the purpose of investigating engine performance and emissions. Performance results showed almost the same results as those of Jet A-1 fuel for these fuels in terms of thermal efficiency, brake-specific fuel consumption, turbine-inlet temperature, and exhaust-gas temperature. The results of exhaust-gas emissions also showed no significant effects on carbon monoxide, unburned hydrocarbon, and nitrogen oxides, while a decrease in smoke opacity was found when blending MBJ with Jet A-1. MBJ performed well in both performance and emissions tests when run in this engine. Thus, MBJ brings hope for the development of aviation biofuels in tropical regions that have an abundance of bioresources, but are limited in technology and investment capital.

Experimental and Numerical Analysis of Gas Premix Turbulent Flames Stabilized in a Swirl Burner with Central Bluff Body

2020 ◽  
Author(s):  
Fernando Biagioli ◽  
Alessandro Innocenti ◽  
Steffen Terhaar ◽  
Teresa Marchione
Keyword(s):  
Numerical Analysis ◽  
Bluff Body ◽  
Reverse Flow ◽  
Flame Stabilization ◽  
Turbulent Flames ◽  
Experimental Investigations ◽  
Swirl Burner ◽  
Stable Flame ◽  
Sudden Transition ◽  
Flame Behaviour

Abstract Lean premixed gas turbulent flames stabilized in the flow generated by an industrial swirl burner with a central bluff body are experimentally found to behave bi-stable. This bi-stable behaviour, which can be triggered via a small change in some of the controlling parameters, for example the bulk equivalence ratio, consists in a rather sudden transition of the flame from completely lifted to well attached to the bluff body. While several experimental investigations exist on this topic, numerical analysis is limited. The present work is therefore also of numerical nature, with a two-fold scope: a) simulation and validation with experiments of the bi-stable flame behaviour via Computational Fluid Dynamics (CFD) in the form of Large Eddy Simulation (LES) and b) analysis of CFD results to shed light on the flame stabilization properties. LES results, in case of the lifted flame, show that the vortex core is sharply precessing at a given frequency. Phase averaging these results at the frequency of precession clearly indicates a counter-intuitive and unexpected presence of reverse flow going all the way through the flame apex and the bluff body tip. A simple one-dimensional flame stabilization model is applied to explain the bi-stable flame behaviour.

Process Studies as Applied to Ceramic Gas Turbine Engine Low-Emission Double-Zone Micro-Diffusion Combustion Chamber

1994 ◽  
Author(s):  
A. V. Sudarev ◽  
Y. I. Zakharov ◽  
E. D. Vlnogradov ◽  
L. S. Butovsky ◽  
E. A. G. Ranovskaya
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Diffusion Combustion ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Turbine Engine ◽  
Operation Conditions ◽  
Fuel Burn ◽  
Heat Regeneration

Initial results of the first step (at Pa = 0.11–0.12 MPa) of an experimental investigation of the basic parameters of full-scale, micro-flame double-zone combustors with flame tubes are presented. This combustion chamber is developed for a 2.5 MW advanced ceramic gas turbine unit. (Sudarev, et al., 1991). This engine, when working at the design operation conditions, has an efficiency range of 41–46%, which is a function of using either intecooling or a heat regeneration scheme. The efficiency is the result of increasing the gas temperature to a maximum turbine inlet temperature of 1250°C and a 2.5 MW pressure ratio of 29. With such high initial parameters of the working media, the problem of nitrogen oxide emissions reduction assumes paramount importance. The objective of the paper is to develop a combustor which would ensure NOx emissions at the design conditions not above 75 mg/Nm3 (at 15% 02) due to application of a double-stage working process of pre-mixture firing. Specific features of fuel burn-up, formation of pollutants at combustion, dependencies of combustor characteristics and upgraded algorithm of combustor loading are also shown.

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