Two Stream Combustion, CFD Simulation ANSYS Fluent TrainingDescriptionCombustion reactions occur when air combines with hydrocarbon fuel, converting fuel energy into heat energy. In some applications, two separate fuel streams are used to carry out this reaction — a configuration known as two-stream combustion, where two fuel streams react with a common oxidizer. This project models a horizontal cylindrical combustion chamber using methane (CH₄) and diesel (C₁₂H₂₃) as fuels, combined with an oxidizer stream to produce combustion. The chamber includes four separate inlets: one each for the primary fuel, secondary fuel, and oxidizing stream. The CH₄ stream enters at a flow rate of 0.02 kg/s and 810 K, the C₁₂H₂₃ stream at 0.02 kg/s and 530 K, and the oxidizer at 1.2 kg/s and 723 K.The Species model was used to define the combustion reaction, configured in non-premixed combustion mode — meaning fuel and oxidizer enter the reaction zone through separate paths without mixing beforehand. This model relies on a mixture fraction representing the mass fraction derived from the fuel stream. Since a secondary fuel is present, the secondary stream option was also activated. The 3D geometry was built in SpaceClaim, representing the interior of a horizontal cylindrical combustion chamber with four inlets for primary fuel, secondary fuel, and airflow. The domain was meshed in ANSYS Meshing using an unstructured mesh totaling 689,854 cells.MethodologyThe simulation was run under steady-state conditions using a pressure-based solver, with gravitational effects excluded.Key model settings included:Turbulence model: Realizable k-epsilon with standard wall functionsSpecies model: Non-premixed combustion with non-adiabatic energy treatment and secondary stream enabledSpecies definitions: Fuel as CH₄, oxidizer as 0.79 N₂/0.21 O₂, secondary stream as C₁₂H₂₃Boundary conditions: Mass flow inlets for fuel (0.02 kg/s, 810 K, mean mixture fraction 1), oxidizer (1.2 kg/s, 723 K, mean mixture fraction 0), and secondary fuel (0.02 kg/s, 530 K, secondary mean mixture fraction 1); pressure outlet at 0 Pa gauge; stationary walls with zero heat fluxSolution methods: SIMPLE pressure-velocity coupling, standard pressure discretization, and first-order upwind schemes applied across momentum, turbulence, mixture fraction, and energy equationsInitialization: Hybrid methodConclusionResults include 2D and 3D contours of pressure, velocity, temperature, and species mass fractions (CH₄, CO₂, C₁₂H₂₃, O₂, H₂O, H₂, CO), along with water-liquid and water-vapor volume fractions. Temperature rises significantly within the reaction zone, where the primary and secondary fuel streams combine with the oxidizing stream inside the chamber, releasing substantial thermal energy. Near the chamber inlet, reactant mass fractions (CH₄, C₁₂H₂₃, and O₂) decrease, while reaction product concentrations (CO₂, CO, H₂O, and others) correspondingly increase — confirming that the combustion reaction proceeds correctly, converting fuel and oxidizer into combustion products.

Combustion Chamber CFD Simulation with Combusting Particle, ANSYS Fluent TrainingDescriptionThis project simulates a combustion chamber involving combusting particles using ANSYS Fluent, with the 3D geometry designed in SpaceClaim and the domain meshed in ANSYS Meshing using a structured grid totaling 125,000 cells. Given the nature of this problem, the simulation was run using a transient solver to capture the time-dependent behavior of the combustion process as it develops within the chamber.MethodologyGiven the continued industrial reliance on coal and the growing importance of developing cleaner coal combustion technologies, accurately modeling coal combustion characteristics remains an important area of study. This simulation uses a two-way Discrete Phase Model (DPM) for particle tracking, with anthracite — the highest-calorific-value type of coal — used as the injected material, while the Species Transport model with its volumetric sub-model was enabled to capture the combustion reaction itself. Particles were injected into the domain at a velocity of 1 m/s and a temperature of 308 K over a 1-second injection period, with turbulence resolved using the standard k-epsilon model and the energy equation enabled to capture temperature variation throughout the domain as combustion progresses.ConclusionResults include 2D and 3D contours of temperature along with particle track visualizations, confirming that effective combustion occurred within the chamber. The average chamber temperature reached 3765.30 K, a result consistent with the high calorific value expected from anthracite combustion and indicative of a well-sustained reaction throughout the injection period.

Combustion Chamber by DPM Spray, CFD Simulation ANSYS Fluent TrainingDescriptionThis project simulates a combustion chamber incorporating the Discrete Phase Model (DPM) using ANSYS Fluent, with the 3D geometry built in SpaceClaim and the mesh generated in ANSYS Meshing. The mesh was initially constructed using tetrahedral elements, then converted into a polyhedral mesh within Fluent itself. Given the nature of this problem, the simulation was run using a transient solver to capture the time-dependent development of the spray and combustion process.MethodologyThis project simulates a gas turbine combustion chamber — a configuration commonly used in jet engine applications — using the Discrete Phase Model alongside the Species Transport model. The effect of injecting sprayed benzene combusting particles is captured using the Eddy-Dissipation combustion approach together with its volumetric sub-model, with the Species Transport model enabled to represent the combustion reaction itself. Both airflow and fuel enter the domain through their respective inlet boundaries at a velocity of 3 m/s, with turbulence resolved using the SST k-omega model and the energy equation enabled to capture temperature variation as combustion progresses.ConclusionResults include contours of temperature and chemical species mass fraction, along with particle track visualizations. The benzene fuel reaches the nozzle as sprayed particles and is carried into the combustion chamber at high velocity, where combustion occurs within the nozzle before the resulting high-speed, high-temperature flow enters the chamber itself. The accompanying animation reveals that the flame front advances more slowly than the fuel penetration, with the injected fuel outpacing the flame as it moves through the domain.

Wet Combustion Using DPM Combusting Particle, ANSYS Fluent TrainingDescriptionThis project simulates the wet combustion of anthracite particles within a combustion chamber using ANSYS Fluent, combining the Discrete Phase Model (DPM) with the Species Transport model to capture the full combustion process — from particle devolatilization through oxidation, producing carbon dioxide and water vapor as reaction products.The geometry was designed in Design Modeler and meshed in ANSYS Meshing using an unstructured grid, subsequently converted into polyhedral cells to reduce computational cost while preserving mesh quality.MethodologyAnthracite particles were modeled with a 2% liquid fraction and injected over a 0.5-second duration, using non-spherical particle shapes combined with a Rosin-Rammler diameter distribution to represent realistic fuel particle behavior. As the particles heat up within the chamber, they undergo devolatilization, releasing volatile fractions that subsequently oxidize alongside the remaining particle mass.The Species Transport model tracks this multi-component reaction process, capturing the release and oxidation of volatiles and the resulting production of carbon dioxide and water vapor, while the coupled DPM framework tracks each particle's individual heating, devolatilization, and combustion behavior throughout its trajectory in the domain.ConclusionThe simulation captures the complete combustion pathway of the anthracite particles, from initial heating through devolatilization and final oxidation, with chamber temperatures reaching as high as 2400 K as combustion proceeds. The resulting temperature and species distribution fields illustrate how particle-scale combustion dynamics — driven by particle size distribution, volatile release timing, and oxidation behavior — collectively shape the chamber's overall thermal and chemical environment, providing insight directly applicable to industrial coal, biomass, and waste combustion system design.

Diesel-Air Mixture Flow with Fuel Droplet Evaporation, CFD TrainingDescriptionThis project investigates the complex dynamics of a diesel-air mixture using ANSYS Fluent, focusing on the interaction between dispersed fuel droplets and the continuous air phase, along with the impact of droplet evaporation on the resulting flow field — analysis directly relevant to engine combustion and fuel spray characterization. The 3D geometry represents a simplified cylindrical combustion chamber, built in SpaceClaim, and meshed in ANSYS Meshing using a grid of over 2 million elements to ensure sufficient resolution for capturing the complex flow phenomena involved.MethodologyA pressure-based, transient solver was used, with the standard k-epsilon turbulence model and standard wall functions applied to capture the flow's turbulent behavior. The energy equation was enabled to resolve the temperature field. The Species Transport model with Eddy-Dissipation for turbulence-chemistry interaction was used to model the mixing of diesel and air. The Discrete Phase Model (DPM) simulated the movement and evaporation of fuel droplets as discrete entities, with two-way coupling enabled to capture the interaction between the dispersed phase (droplets) and the continuous phase (air). Temperature-dependent latent heat effects were also included to account for the energy consumed during droplet evaporation.Droplet evaporation was permitted throughout the domain, capturing the associated mass transfer process. Diesel fuel was injected from the center of the inlet, with air entering from the surrounding region, and the simulation ran for 5 seconds to capture the mixture's transient behavior.ConclusionThe simulation results provide detailed insight into the diesel-air mixture's flow behavior: Density contours show higher mixture density near the injection point, decreasing as the diesel jet spreads and mixes with the surrounding air — reflecting diesel's higher density relative to air. Mass fraction contours for diesel (C10) show the fuel jet extending into the chamber, with concentration progressively decreasing as mixing occurs, while nitrogen mass fraction contours show a corresponding decrease near the injection point as the diesel jet displaces the surrounding air.Static temperature contours reveal a significant temperature rise where the diesel jet interacts with the air, indicating heat release associated with combustion. Turbulence intensity is elevated near the jet, reflecting strong mixing activity, while velocity magnitude contours show peak velocity at the jet core, gradually decreasing as the jet spreads — illustrating momentum transfer from the injected diesel. Particle trajectories from the DPM model illustrate the dispersion and evaporation of individual fuel droplets within the chamber, with smaller droplets evaporating faster and exhibiting shorter residence times. Particle residence time visualizations further show how time spent within the domain varies depending on droplet size and injection location.

Liquid Fuel Combustion Inside a Chamber Using DPMDescriptionLiquid fuel combustion processes have been at the core of energy production and propulsion systems for over a century, providing the necessary thrust and power for a wide range of applications. Among the various fuel types, liquid ethanol (C₂H₅OH) has gained attention as a renewable and cleaner-burning alternative to fossil fuels, and when paired with an oxidizer such as nitrous oxide (N₂O), it can undergo a vigorous combustion reaction that releases energy for various industrial and technological applications.This project models that ethanol-nitrous oxide combustion process using ANSYS Fluent, with the geometry designed in SpaceClaim. The combustion chamber measures 6000 mm in diameter, featuring a fuel nozzle positioned at its center. The domain was meshed in ANSYS Meshing, generating a total of 769,000 elements.MethodologyThe liquid fuel droplets were modeled using a two-way Discrete Phase Model (DPM), with the continuous phase solved under steady-state conditions while the discrete phase was tracked unsteadily to capture droplet behavior over time. Turbulence was resolved using the standard k-epsilon model, while the combustion of ethanol and nitrous oxide was captured using the Species Transport model with its volumetric reaction option, coupled with the Eddy-Dissipation turbulent-chemistry interaction model.ConclusionThe simulation proceeded in two major stages. First, the continuous phase was solved, allowing the velocity and pressure fields to reach steady conditions, with the chamber's average temperature settling at 320 K while filled with nitrous oxide. Once this steady state was established, fuel injection began: ethanol droplets measuring 0.5 mm were injected at a temperature of 273.15 K.As the fuel droplets absorbed heat from the surrounding environment, their temperature rose over time until reaching the devolatilization point, at which ethanol vapor was released and given the opportunity to mix with the nitrous oxide oxidizer and react. This reaction drove a dramatic temperature rise, with the chamber's average temperature climbing to approximately 460 K, while producing combustion products according to the following reaction:3C₂H₅OH + 2N₂O → 3CO₂ + 4H₂O + 2N₂

Premixed Combustion in a Porous Zone, CFD Simulation ANSYS Fluent TrainingDescriptionThis project simulates premixed combustion within a porous zone using ANSYS Fluent, examining how the presence of porous media affects combustion behavior. Porous media combustion, often implemented through matrix-stabilized burners, works by allowing the flame to propagate through the solid matrix of a porous material rather than in free space. The solid matrix absorbs and redistributes heat through conduction and radiation, which tends to broaden the reaction zone, lower peak flame temperatures, and improve flame stability compared to conventional open-flame combustion. This approach is widely used in industrial burners and heating applications where more uniform heat distribution, reduced thermal peaks, and extended operational stability are desired — making the comparison between porous and non-porous combustion a valuable way to quantify these effects. The 3D geometry was designed in Design Modeler, consisting of two sections: a lower preheating region and an upper stable-burn region. The domain was meshed in ANSYS Meshing using a structured grid totaling 8,700 cells.MethodologyThis simulation models a simple premixed combustion case within a porous zone, examining how the porous structure influences combustion temperature and helps stabilize the flame — configured as a matrix-stabilized burner. Results were compared against an equivalent premixed combustion case without porosity to isolate the effect of the porous medium. The Species Transport model was used to represent the combustion process, with the incoming mixture flow set at a methane mass fraction of 0.23 and an oxygen mass fraction of 0.77. Combustion was initiated using the ignition spark sub-model. Gravitational effects were included at -9.81 m/s² along the y-axis, and turbulence was resolved using the SST k-omega model.ConclusionResults include 3D velocity fields, air and water volume fraction contours, and simulation animation. The findings show that the porous zone reduces static temperature within the combustion region and promotes a more uniform, stable combustion process compared to an equivalent case without porosity — consistent with the general behavior expected of matrix-stabilized porous burners, where the solid matrix's heat redistribution moderates and stabilizes the reaction zone.

Lime Kiln Combustion CFD Simulation by ANSYS Fluent, TutorialDescriptionThis project simulates the combustion process of methane gas within a vertical lime kiln using ANSYS Fluent. The 3D geometry was designed in Design Modeler as a semi-modeled vertical furnace, leveraging the structure's symmetry to reduce computational cost. The model includes four fuel inlets positioned around the middle of the kiln's side surface, a fifth fuel inlet at the furnace center, a primary air inlet at the center of the kiln, a secondary air inlet in the furnace's lower section, an outlet for reaction products in the lower section, and a dedicated outlet for gas discharge at the top of the furnace. The domain was meshed in ANSYS Meshing, totaling 2,219,550 elements.MethodologyA vertical lime kiln consists of two main functional zones: the combustion zone and the preheating zone. Fuel and air enter through the middle of the kiln and undergo a combustion reaction, releasing substantial heat and raising the internal temperature. Separately, calcium carbonate (limestone) is introduced from the upper section of the kiln. As it absorbs heat generated by the combustion process, it undergoes a distinct thermal decomposition reaction, releasing carbon dioxide and producing calcium oxide (quicklime). This project focuses specifically on modeling the combustion reaction itself within the kiln, rather than the limestone decomposition process.The combustion reaction models a chemical interaction between air and methane, represented using the Species Transport model with its volumetric reaction sub-model. Flow entering through the four side inlets and the central inlet consists of 0.9 methane (CH₄) and 0.1 nitrogen (N₂), entering at 1.357 m/s and 300 K, alongside a simultaneous airflow entering from the central region.The model includes two outlets: reaction products exit through the bottom outlet at atmospheric pressure, while excess gases are drawn out through a separate suction-fan-driven outlet. Porous media was incorporated within the kiln, modeled as aluminum with a porosity coefficient of 0.3, an inertial resistance of 907.4 1/m, and a viscous resistance of 1,100,000 1/m². The standard k-epsilon turbulence model and the energy equation were used to solve the turbulent flow field and capture temperature variation throughout the domain.ConclusionResults include 2D and 3D contours of pressure, temperature, velocity, and mass fractions for O₂, CH₄, H₂O, CO₂, N₂, and CaCO₃. The results confirm that reaction products — including carbon dioxide and water vapor — form as a result of the combustion reaction between methane fuel and air, releasing significant heat in the process. This generated heat is precisely what drives the subsequent dissociation of calcium carbonate into quicklime, linking the combustion process directly to the kiln's primary industrial function.

Radiation Heat Transfer in Combustion Chamber, ANSYS Fluent TrainingDescriptionThis project investigates the steady combustion of methane and air within a simple extended cubical combustion chamber using ANSYS Fluent, with particular attention to radiation heat transfer — a critical consideration given the extremely high temperatures involved in combustion chambers. The 3D geometry was designed in Design Modeler and meshed in ANSYS Meshing, totaling 384,112 elements.MethodologyThe simulation captures a mixture static temperature reaching a maximum of 3500 K within the chamber. Methane and air enter the domain through separate inlets — methane through a single inlet, while airflow enters through two inlets to promote a more uniform fuel-air mixture. Air and fuel enter at mass flow rates of 0.00468 kg/s and 0.000205 kg/s, respectively.The chemical reaction between methane and air produces CO₂ and H₂O; since the combustion is air-rich, oxygen and nitrogen remain unconsumed at the end of the reaction. The Species Transport model was activated to simulate combustion, with volumetric reactions enabled.Given the high temperatures generated within the chamber, radiation heat transfer required explicit modeling, so the Discrete Ordinates (DO) model was also enabled. Turbulence was resolved using the RNG k-epsilon model, chosen for its ability to more accurately capture intense heat flux generation within the domain compared to other k-epsilon variants.ConclusionResults include 2D contours of temperature, velocity, species mass fraction, streamlines, and velocity vectors throughout the combustion chamber, with an outlet mixture mass flow rate of 0.004885042 kg/s. The primary combustion process occurs within the chamber itself, clearly visible in the temperature and reaction heat contours, which show the maximum temperature gradient and peak reaction heat concentrated in this region. The combustion process is similarly evident in the species mass fraction contours — the CO₂ mass fraction, for instance, shows a sharp increase corresponding directly to the combustion reaction taking place.

Thermoacoustic Analysis in Combustion Chamber, CFD Simulation TutorialDescriptionThis project, covering non-premixed combustion and acoustics together, investigates a thermoacoustic phenomenon within a combustion chamber using ANSYS Fluent. In thermoacoustic systems, heat is converted into sound waves, which can then be harnessed for tasks such as pumping heat or generating electricity. Since the process involves no moving parts, it offers a reliable, low-maintenance approach to energy conversion.Methane and oxygen enter the domain through separate inlet boundaries at mass flow rates of 0.001 kg/s and 0.025 kg/s, respectively, mixing and combusting within the chamber. This simulation extracts both the Acoustic Power Level (dB) and Surface Acoustic Power Level (dB) using the steady-state acoustic model available in ANSYS Fluent — the former measuring total sound power, and the latter measuring sound power per unit surface area. The geometry was built in SpaceClaim, with the mesh generated in ANSYS Meshing.MethodologyCombustion was modeled using the Non-Adiabatic, Non-Premixed Combustion model, which accounts for heat loss occurring during combustion — reflecting the reality that some generated heat escapes to the surroundings rather than remaining fully contained. This makes the model more representative of practical scenarios where such losses can't be neglected. Acoustic behavior was captured using the Broadband Noise Source model, which predicts the broadband noise generated by turbulent flow within the CFD simulation.ConclusionThe extracted results include contours of several key parameters. The fuel's mass fraction shows it entering the domain from the center of the inlet plate, while air — defined with a 0.23 oxygen mass fraction and the remainder nitrogen — enters the surrounding zone around the fuel inlet. Mass fraction contours of the combustion reaction products are similarly visible throughout the domain.Acoustic results include the Surface Acoustic Power Level across the chamber walls and the Acoustic Power Level across a plane defined at the chamber's center. The maximum Surface Acoustic Power Level reached 73.56 dB, while the corresponding Acoustic Power Level value was somewhat lower, at 62.93 dB — illustrating how combustion-driven sound generation varies between the chamber's bounding surfaces and its interior flow field.