LES of Hydrogen Enriched Methane/Air Combustion in the SGT-800 Burner at Real Engine Conditions

2018 ◽  
Author(s):  
Daniel Moëll ◽  
Daniel Lörstad ◽  
Xue-Song Bai
Keyword(s):  
High Pressure ◽  
Mixture Fraction ◽  
Flame Structure ◽  
Flame Temperature ◽  
Flow Simulation ◽  
Sudden Expansion ◽  
Inlet Temperature ◽  
Complex Flow ◽  
Control Variables ◽  
Hydrogen Enrichment

DLE (Dry Low Emission) techniques are widely used today to reduce the harmful NOx emissions associated with high combustion temperatures. In many DLE systems the fuel and air are pre-mixed which effectively keep the flame temperature as low as possible, ideally equal to the turbine inlet temperature. By using pre-mixing stability issues such as flash back and combustion driven dynamics may occur. Operating the engine with hydrogen diluted natural gas will decrease the flash back limits of the system due to the high diffusivity and highly reactive nature of hydrogen. In this study the stability effects of hydrogen diluted into methane in the Siemens SGT-800 combustor is studied. The SGT-800 combustor is an annular combustor where the flame is stabilized using a swirl burner combined with a sudden expansion combustor. The expansion gives rise to a vortex break down where the flame stabilizes in the local low speed zones. Here a single burner sector is studied using the flow solver Siemens PLM software STAR-CCM+. The turbulence is simulated through the use of LES (Large Eddy Simulation) where the largest energy carrying flow scales are resolved and only the smaller scales are modelled. The chemistry is coupled to the turbulent flow simulation by the use of FGM (Flamelet Generated Manifolds) which are integrated using presumed probability density functions. The FGM approach assumes that the local flame structure is laminar and that all species across a flame can be related to a set of control variables. The control variables in this case are the heat loss, the mixture fraction and its variance and a reaction progress variable. In this paper two effects are studied, first the transition from an atmospheric flame to a pressurized flame and second the effect of hydrogen enrichment. The flame shape and position are mainly affected by the transition from atmospheric to high pressure, where the power density increases by almost a factor of 20. The flame is moving further upstream closer to the burner in all pressurized cases. The hydrogen enrichment plays a strong role in how the combustion driven dynamics is coupling with the acoustics of the rig. The high pressure pure methane case show a strong pressure peak whereas the hydrogen enriched case dampens that peak and distributes the energy to other frequencies. This work shows that high fidelity CFD is capable of capturing complex flow and flame interactions such as thermoacoustic instabilities in industrial scale systems.

Measurements of Hydrogen-Enriched Combustion of JP-8 in Open Flame

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Michael Seibert ◽  
Sen Nieh
Keyword(s):  
Flame Structure ◽  
Flame Temperature ◽  
Operational Reliability ◽  
Initial Energy ◽  
Pollutant Emissions ◽  
Gaseous Emissions ◽  
Open Flame ◽  
Point Of Use ◽  
Hydrogen Enrichment ◽  
Secondary Air

Hydrogen enrichment is presented as a control parameter to improve JP-8 combustion. Research in fuel reforming gives an opportunity for hydrogen production at the point of use. Hydrogen-enriched combustion of JP-8 seeks to take advantage of the energy density of JP-8 and the combustibility of hydrogen. At low power output (<2 kWe), technologies such as Stirling engines, thermoelectric, and thermophotovoltaic generators have the potential to compete with diesel engines, but require reliable JP-8 combustion. Experiments were conducted with atomized JP-8 in a 5 kWth open flame, based on a 500 W power source. JP-8 is sprayed through an air-atomizing nozzle. Hydrogen was added to either the atomizing air or to a concentric tube supplying the main combustion air. In these experiments, hydrogen represented up to 26% of the fuel energy contribution (EC). During hydrogen enrichment, JP-8 flow rate was reduced to maintain constant fuel energy input. Temperature is measured vertically and laterally through the flame. Temperature profiles show that combustion shifts toward the nozzle as hydrogen is added. Hydrogen in the secondary air maintains diffusion flame behavior, but earlier in the flame. Hydrogen in the nozzle air creates a premixed pilot flame structure in the center of the flame. This premixed hydrogen and air flame provides initial energy to speed droplet heating and vaporization, producing higher peak temperatures than the other cases studied. Gaseous emissions are measured above the visible flame. Hydrogen enrichment by both methods reduced unburned hydrocarbon emissions by up to 70%. The advantages provided by hydrogen enrichment represent opportunities for reduced size, improved operational reliability and control, and reduced pollutant emissions.

scholarly journals Fire Safety Evaluation of High-Pressure Ammonia Storage Systems

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 520
Author(s):  
Yong Ho Chung ◽  
Won-Ju Lee ◽  
Jun Kang ◽  
Sung Hwan Yoon
Keyword(s):  
High Pressure ◽  
Strain Rate ◽  
Oxygen Concentration ◽  
Flame Structure ◽  
Flame Temperature ◽  
Safety Evaluation ◽  
Fire Spread ◽  
Flammability Limit ◽  
Radiation Heat Loss ◽  
Auto Ignition

Ammonia combustion is a promising energy source as a carbon free fuel without greenhouse gas emissions. However, since the auto-ignition temperature is 651 degrees Celsius and the range of flammability limit is not wide compared to other fuels, fundamental studies on ammonia fires have rarely been conducted so far. Therefore, this study aims to numerically estimate fire spread characteristics when ammonia fuel in a high-pressure state leaks to the outside, especially focusing on the flammability limit according to oxygen concentration. Three kinds of reaction mechanism for numerical analysis were adopted to compare the flame structure, flammability limit, and combustion characteristics. Plank-mean absorption coefficients of nitrogen species were taken for the radiation model, in addition to the optically thin model. The effect of radiation heat loss could be identified from the maximum flame temperature trend at a low strain rate. It was confirmed that the pyrolysis of ammonia in the preheated zone results in hydrogen production, and the generated hydrogen contributes to heat release rate in the flame zone. It is found that the contribution of hydrogen would be an important role in the flammability limit of ammonia combustion. Finally, Karlovitz and Peclet numbers showed well the extinction behaviors of ammonia combustion as a result of LOC (Limit Oxygen Concentration) analysis as a function of global strain rate.

scholarly journals Investigation of Thermal Radiation from Soot Particles and Gases in Oxy-Combustion Counter-Flow Flames

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1756
Author(s):  
Chaoyang Wang ◽  
Guangtong Tang ◽  
Huibo Yan ◽  
Lujiang Li ◽  
Xiaopei Yan ◽  
...  
Keyword(s):  
Thermal Radiation ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Mixture Fraction ◽  
Flame Structure ◽  
Flame Temperature ◽  
Stoichiometric Mixture ◽  
Particle Radiation ◽  
Mixture Ratio ◽  
Soot Particles

Oxy-combustion with high flame temperature, low heat loss, high combustion efficiency, and low NOx emissions is being extensively studied. The thermal radiation from soot particles and gases in oxy-combustion accounts for the vast majority of the total heat transfer. Based on a detailed chemical reaction mechanism coupled with the soot particle dynamics model and optically thin radiation model, the influence of the flame structure and temperature distribution on the thermal radiation in oxygen-enriched counterflow diffusion flames was studied in this paper. The results revealed that reasonable assignment of total recycled flue gas and the degree of dilution of fuel and oxidant were critical, which can be used to adjust the overall radiation situation of the flame. At the same adiabatic flame temperature, as the fuel concentration decreased and the oxidant concentration increased (the stoichiometric mixture ratio is from 0.3 to 0.6), the soot formation decreased, which led to the particle radiation disappearing while the main radiation zone of gases moved 0.04 cm toward the fuel side. At the same stoichiometric mixture fraction (0.4), the radiation area was broadened and the radiation of soot particles was gradually enhanced with the adiabatic flame increasing from 2300 K to 2700 K.

Internal Gas Analysis and CFD Predictions of Double Contra-Rotating Axial Swirlers With Fuel Injection From Between the Two Outlets

2012 ◽  
Author(s):  
Phil T. King ◽  
T. B. Mat Lazim ◽  
Gordon E. Andrews ◽  
Mohamed M. Pourkashanian ◽  
Andy C. McIntosh
Keyword(s):  
Equivalence Ratio ◽  
Schmidt Number ◽  
Mixture Fraction ◽  
Flame Temperature ◽  
Combustion Model ◽  
Inlet Temperature ◽  
Processing Application ◽  
Combustion Models ◽  
Turbulent Schmidt Number ◽  
Air Mixing

A double contra-rotating axial swirler was investigated at 0.38 equivalence ratio and 600K inlet temperature at 1 bar, both experimentally and using CFD. Natural gas fuel was injected from between the two contra-rotating flows. The experimental results showed that whilst the NOx emissions were relatively high, the system has excellent flame stability characteristics meaning the flame could be maintained at very low fuel-air ratios, down to an equivalence ratio of around 0.28. CFD predictions were carried out using the equilibrium pdf combustion model alongside the partially premixed combustion model using default model constants, and the NOx model was applied as a post-processing application. The results showed that whilst the location and shape of the flame and the combustor fuel-air distribution could not be precisely captured, the peak temperature, CO, UHC and NOx levels were correctly predicted. The influence of the turbulent Schmidt number, Sct, was therefore investigated in an attempt to improve the predictions. Lower values offered an improvement in the fuel-air mixing predictions, but not in the combustion predictions, where the peak flame temperature could only be predicted correctly when using the default value of Sct = 0.85. This indicates that the use of a universal turbulent Schmidt number for both the fuel-air mixing and combustion models may not be suitable for the present swirler and combustor configuration, therefore future work will look to use a separate value of Sct for the mixture fraction than for the pdf combustion models.

Study on the Effect of Adiabatic Flame Temperature on NOx Formation Using Ethanol Gasoline Blend in SI Engine

2013 ◽  
Vol 781-784 ◽  
pp. 2471-2475 ◽  
Author(s):  
B. M. Masum ◽  
M.A. Kalam ◽  
H.H. Masjuki ◽  
S. M. Palash
Keyword(s):  
Equivalence Ratio ◽  
Gasoline Engine ◽  
Flame Temperature ◽  
Inlet Temperature ◽  
Si Engine ◽  
Nox Formation ◽  
Adiabatic Flame Temperature ◽  
No Formation ◽  
Blended Fuel ◽  
Active Research

Active research and development on using ethanol fuel in gasoline engine had been done for few decades since ethanol served as a potential of infinite fuel supply. This paper discussed analytically and provides data on the effects of compression ratio, equivalence ratio, inlet temperature, inlet pressure and ethanol blend in cylinder adiabatic flame temperature (AFT) and nitrogen oxide (NO) formation of a gasoline engine. Olikara and Borman routines were used to calculate the equilibrium products of combustion for ethanol gasoline blended fuel. The equilibrium values of each species were used to predict AFT and the NO formation of combustion chamber. The result shows that both adiabatic flame temperature and NO formation are lower for ethanol-gasoline blend than gasoline fuel.

Finite Element Volume Analysis of Propane Preheated Air Flame Passing Through a Minichannel

2014 ◽  
Author(s):  
Masoud Darbandi ◽  
Majid Ghafourizadeh ◽  
Gerry E. Schneider
Keyword(s):  
Finite Element ◽  
Radiation Effects ◽  
Mixture Fraction ◽  
Flame Structure ◽  
Current Method ◽  
Reacting Flow ◽  
Wall Functions ◽  
Flamelet Model ◽  
Combustion Modeling ◽  
Detailed Kinetics

A hybrid finite-element-volume FEV method is extended to simulate turbulent non-premixed propane air preheated flame in a minichannel. We use a detailed kinetics scheme, i.e. GRI mechanism 3.0, and the flamelet model to perform the combustion modeling. The turbulence-chemistry interaction is taken into account in this flamelet modeling using presumed shape probability density functions PDFs. Considering an upwind-biased physics for the current reacting flow, we implement the physical influence upwinding scheme PIS to estimate the cell-face mixture fraction variance in this study. To close the turbulence closure, we employ the two-equation standard κ-ε turbulence model incorporated with suitable wall functions. Supposing an optically thin limit, it needs to take into account radiation effects of the most important radiating species in the current modeling. Despite facing with so many flame instabilities in such small size configuration, the current method performs suitably with proper convergence, and the encountered instabilities are damped out automatically. Comparing with the experimental measurements, the current extended method accurately predicts the flame structure in the minichannel configuration.

scholarly journals Impact of High-Pressure Homogenization Parameters on Physicochemical Characteristics, Bioactive Compounds Content, and Antioxidant Capacity of Blackcurrant Juice

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1802
Author(s):  
Bartosz Kruszewski ◽  
Katarzyna Zawada ◽  
Piotr Karpiński
Keyword(s):  
High Pressure ◽  
Vitamin C ◽  
Antioxidant Capacity ◽  
Bioactive Compounds ◽  
Titratable Acidity ◽  
Physicochemical Characteristics ◽  
Food Preservation ◽  
Inlet Temperature ◽  
High Pressure Homogenization

High-pressure homogenization (HPH) is one of the food-processing methods being tested for use in food preservation as an alternative to pasteurization. The effects of the HPH process on food can vary depending on the process parameters used and product characteristics. The study aimed to investigate the effect of pressure, the number of passes, and the inlet temperature of HPH processing on the quality of cloudy blackcurrant juice as an example of food rich in bioactive compounds. For this purpose, the HPH treatment (pressure of 50, 150, and 220 MPa; one, three, and five passes; inlet temperature at 4 and 20 °C) and the pasteurization of the juice were performed. Titratable acidity, pH, turbidity, anthocyanin, vitamin C, and total phenolics content, as well as colour, and antioxidant activity were measured. Heat treatment significantly decreased the quality of the juice. For processing of the juice, the best were the combinations of the following: one pass, the inlet temperature of 4 °C, any of the used pressures (50, 150, and 220 MPa); and one pass, the inlet temperature of 20 °C, and the pressure of 150 MPa. Vitamin C and anthocyanin degradation have been reported during the HPH. The multiple passes of the juice through the machine were only beneficial in increasing the antioxidant capacity but negatively affected the colour stability.

Low Emissions Combustion for the Regenerative Gas Turbine: Part 1—Theoretical and Design Considerations

1974 ◽  
Vol 96 (1) ◽  
pp. 32-48 ◽  
Author(s):  
W. R. Wade ◽  
P. I. Shen ◽  
C. W. Owens ◽  
A. F. McLean
Keyword(s):  
Gas Turbine ◽  
Flame Temperature ◽  
Homogeneous System ◽  
Automotive Application ◽  
Inlet Temperature ◽  
Oxides Of Nitrogen ◽  
Turbine Engine ◽  
Homogeneous Combustion ◽  
Hc Emissions ◽  
Model Year

This first part, of a two part paper, reviews the NOx emission problem of the regenerative gas turbine engine for automotive application. It discusses the problem of fuel droplet burning, which causes heterogenous combustion with resulting high flame temperatures and high levels of oxides of nitrogen. The paper proposes means to achieve homogeneous combustion and shows that, even with this approach, flame temperatures need to be closely controlled to effect a compromise between NOx, CO, and HC emissions in order to meet the stringent numerical levels of emissions specified by the Federal standards for 1976 and subsequent model year automobiles. The paper shows that combustor inlet temperature of a homogeneous system has little effect, theoretically, on computed NOx emissions expressed as grams per mile, thereby strengthening the case for the regenerative turbine engine. A design concept for homogeneous combustion with controlled flame temperature is discussed.

Aero-Thermodynamic Loss Analysis in Cases of Normal Shock Wave-Turbulent Shear Layer Interaction

1997 ◽  
Vol 119 (2) ◽  
pp. 297-303 ◽  
Author(s):  
J. K. Kaldellis
Keyword(s):  
Shear Layer ◽  
Practical Interest ◽  
Flow Simulation ◽  
Strong Shock ◽  
Turbulent Shear ◽  
Complex Flow ◽  
Loss Model ◽  
Layer Interaction ◽  
Loss Analysis ◽  
Shock Loss

Transonic-supersonic decelerating flow cases appearing in modern turbomachines are some of the most complex flow cases in fluid mechanics which also present practical interest. In the present work, a closed and coherent shock loss model is proposed based on the complete viscous flow simulation using some fast and reliable computational tools. The resulting model describes accurately the entropy rise and the total pressure loss in cases of strong shock-shear layer interaction and cancels the need to use low speed correlations modified for compressibility effects and extrapolated to transonic-supersonic flow cases. The accuracy and the reliability of the proposed shock-loss model are verified using detailed experimental data concerning various flow cases which present either flow separation or industrial interest.

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