Topic
Combustor
About: Combustor is a research topic. Over the lifetime, 57580 publications have been published within this topic receiving 492450 citations. The topic is also known as: burner & combustion chamber.
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TL;DR: In this paper, the authors present a discussion of different methods which can be used to suppress combustion instabilities using active control, as well as a review of the work which has recently been performed in this area of combustion research.
789 citations
01 Jan 2019
TL;DR: In this article, the potential use of ammonia as a carbon-free fuel is discussed, and recent advances in the development of ammonia combustion technology and its underlying chemistry are discussed. But, there are several challenges in ammonia combustion, such as low flammability, high NOx emission, and low radiation intensity.
Abstract: This paper focuses on the potential use of ammonia as a carbon-free fuel, and covers recent advances in the development of ammonia combustion technology and its underlying chemistry. Fulfilling the COP21 Paris Agreement requires the de-carbonization of energy generation, through utilization of carbon-neutral and overall carbon-free fuels produced from renewable sources. Hydrogen is one of such fuels, which is a potential energy carrier for reducing greenhouse-gas emissions. However, its shipment for long distances and storage for long times present challenges. Ammonia on the other hand, comprises 17.8% of hydrogen by mass and can be produced from renewable hydrogen and nitrogen separated from air. Furthermore, thermal properties of ammonia are similar to those of propane in terms of boiling temperature and condensation pressure, making it attractive as a hydrogen and energy carrier. Ammonia has been produced and utilized for the past 100 years as a fertilizer, chemical raw material, and refrigerant. Ammonia can be used as a fuel but there are several challenges in ammonia combustion, such as low flammability, high NOx emission, and low radiation intensity. Overcoming these challenges requires further research into ammonia flame dynamics and chemistry. This paper discusses recent successful applications of ammonia fuel, in gas turbines, co-fired with pulverize coal, and in industrial furnaces. These applications have been implemented under the Japanese ‘Cross-ministerial Strategic Innovation Promotion Program (SIP): Energy Carriers’. In addition, fundamental aspects of ammonia combustion are discussed including characteristics of laminar premixed flames, counterflow twin-flames, and turbulent premixed flames stabilized by a nozzle burner at high pressure. Furthermore, this paper discusses details of the chemistry of ammonia combustion related to NOx production, processes for reducing NOx, and validation of several ammonia oxidation kinetics models. Finally, LES results for a gas-turbine-like swirl-burner are presented, for the purpose of developing low-NOx single-fuelled ammonia gas turbine combustors.
768 citations
TL;DR: In this article, the authors present a review of some facets of combustion control and focus on the sensors that take or could take part to combustion control solutions, together with the associated control concepts.
640 citations
TL;DR: A review of the literature on the effects of freestream turbulence, surface curvature, and hole shape on the performance of film cooling is presented in this article. But, it is difficult to predict film cooling performance because of the inherent complex flowfields along the airfoil component surfaces in turbine engines.
Abstract: The durability of gas turbine engines is strongly dependent on the component temperatures. For the combustor and turbine airfoils and endwalls, film cooling is used extensively to reduce component temperatures. Film cooling is a cooling method used in virtually all of today's aircraft turbine engines and in many power-generation turbine engines and yet has very difficult phenomena to predict. The interaction of jets-in-crossflow, which is representative of film cooling, results in a shear layer that leads to mixing and a decay in the cooling performance along a surface. This interaction is highly dependent on the jet-to-crossflow mass and momentum flux ratios. Film-cooling performance is difficult to predict because of the inherent complex flowfields along the airfoil component surfaces in turbine engines. Film cooling is applied to nearly all of the external surfaces associated with the airfoils that are exposed to the hot combustion gasses such as the leading edges, main bodies, blade tips, and endwalls. In a review of the literature, it was found that there are strong effects of freestream turbulence, surface curvature, and hole shape on the performance of film cooling. Film cooling is reviewed through a discussion of the analyses methodologies, a physical description, and the various influences on film-cooling performance.
636 citations
TL;DR: In this paper, the authors consider the relationship between size and pressure loss flow in the Annulus Flow through Liner Holes and describe the effect of Inlet Flow conditions on Inlet flow conditions.
Abstract: Basic Considerations Introduction Early Combustor Developments Basic Design Features Combustor Requirements Combustor Types Diffuser Primary Zone Intermediate Zone Dilution Zone Fuel Preparation Wall Cooling Combustors for Low Emissions Combustors for Small Engines Industrial Chambers Combustion Fundamentals Introduction Classification of Flames Physics or Chemistry? Flammability Limits Global Reaction-Rate Theory Laminar Premixed Flames Laminar Diffusion Flames Turbulent Premixed Flames Flame Propagation in Heterogeneous Mixtures of Fuel Drops, Fuel Vapor, and Air Droplet and Spray Evaporation Ignition Theory Spontaneous Ignition Flashback Stoichiometry Adiabatic Flame Temperature Diffusers Introduction Diffuser Geometry Flow Regimes Performance Criteria Performance Effect of Inlet Flow Conditions Design Considerations Numerical Simulations Aerodynamics Introduction Reference Quantities Pressure-Loss Parameters Relationship between Size and Pressure Loss Flow in the Annulus Flow through Liner Holes Jet Trajectories Jet Mixing Temperature Traverse Quality Dilution Zone Design Correlation of Pattern Factor Data Rig Testing for Pattern Factor Swirler Aerodynamics Axial Swirlers Radial Swirlers Flat Vanes versus Curved Vanes Combustion Performance Introduction Combustion Efficiency Reaction-Controlled Systems Mixing-Controlled Systems Evaporation-Controlled Systems Reaction- and Evaporation-Controlled Systems Flame Stabilization Bluff-Body Flameholders Mechanisms of Flame Stabilization Flame Stabilization in Combustion Chambers Ignition Assessment of Ignition Performance Spark Ignition Other Forms of Ignition Factors Influencing Ignition Performance The Ignition Process Methods of Improving Ignition Performance Fuel Injection Basic Processes in Atomization Classical Mechanism of Jet and Sheet Breakup Prompt Atomization Classical or Prompt? Drop-Size Distributions Atomizer Requirements Pressure Atomizers Rotary Atomizers Air-Assist Atomizers Airblast Atomizers Effervescent Atomizers Vaporizers Fuel Nozzle Coking Gas Injection Equations for Mean Drop Size SMD Equations for Pressure Atomizers SMD Equations for Twin-Fluid Atomizers SMD Equations for Prompt Atomization Internal Flow Characteristics Flow Number Discharge Coefficient Spray Cone Angle Radial Fuel Distribution Circumferential Fuel Distribution Combustion Noise Introduction Direct Combustion Noise Combustion Instabilities Control of Combustion Instabilities Modeling of Combustion Instabilities Heat Transfer Introduction Heat-Transfer Processes Internal Radiation External Radiation Internal Convection External Convection Calculation of Uncooled Liner Temperature Film Cooling Correlation of Film-Cooling Data Practical Applications of Transpiration Cooling Advanced Wall-Cooling Methods Augmented Cold-Side Convection Thermal Barrier Coatings Materials Liner Failure Modes Emissions Introduction Concerns Regulations Mechanisms of Pollutant Formation Pollutants Reduction in Conventional Combustors Pollutants Reduction by Control of Flame Temperature Dry Low-Oxides of Nitrogen Combustors Lean Premix Prevaporize Combustion Rich-Burn, Quick-Quench, Lean-Burn Combustor Catalytic Combustion Correlation and Modeling of Oxides of Nitrogen and Carbon Monoxide Emissions Concluding Remarks Alternative Fuels Introduction Types of Hydrocarbons Production of Liquid Fuels Fuel Properties Combustion Properties of Fuels Classification of Liquid Fuels Classification of Gaseous Fuels Alternative Fuels Synthetic Fuels Index References appear at the end of each chapter
610 citations