Non-Premixed Combustion — ANSYS Fluent CFD SimulationDescriptionThis project simulates non-premixed combustion in a 2D combustion chamber, where air and hydrocarbon fuel enter through two separate inlets and react to release the fuel's chemical energy as heat. It's a foundational study in reacting-flow CFD — the configuration that describes most real burners, furnaces, and gas-turbine combustors, where fuel and oxidizer are deliberately kept apart until they meet in the reaction zone. Within the Combustion: Beginner CFD Training Package, this project introduces the foundational combustion model — the mixture-fraction approach — establishing the core reacting-flow method the later chamber, swirl, and flare cases build on.MethodologyThe key modeling choice is the non-premixed (mixture-fraction) approach within Fluent's Species Transport framework. Instead of tracking every reaction rate directly, the model solves transport equations for the mixture fraction — the local mass fraction originating from the fuel stream — and reads the resulting species and temperatures from pre-computed chemistry. This is what makes non-premixed combustion both efficient and stable: the chemistry is folded into the mixture fraction, so you model the mixing and let the thermochemistry follow. By definition, the fuel and oxidizer enter through independent paths and do not premix before reaching the chamber. An air stream (N₂ at mass fraction 0.767, O₂ at 0.233) enters at 300 K and 1.19 kg/s, while a pure CH₄ (methane) stream enters at 300 K and 0.019 kg/s through a separate inlet. The geometry is built in Design Modeler and meshed in ANSYS Meshing as an unstructured mesh of 11,202 cells.AnalysisThe results provide contours of pressure, temperature, velocity, and density, plus mass-fraction fields for O₂, CH₄, H₂O, CO₂, N₂, CO, and C₂H₆, along with in-chamber pathlines. The fields confirm a properly anchored combustion reaction: methane and air react where the streams meet, consuming reactants and producing CO₂, H₂O, and intermediates like CO — and the temperature field maps the flame and hot-product zone exactly where the mixture fraction is near stoichiometric. By the end of this project, you'll be able to set up Species Transport with the non-premixed mixture-fraction model, define separate fuel and oxidizer inlets with realistic compositions and flow rates, and read flame structure and product formation from temperature and species contours.

Bluff-Body Mild Burner CFD Simulation, ANSYS Fluent TrainingDescriptionThis project simulates combustion within a bluff-body mild burner using ANSYS Fluent. A burner is a device that combines a controlled amount of air with fuel within a safe enclosed space, converting fuel energy into heat energy while producing combustion gases as a byproduct. Since the resulting flame transfers heat into the chamber interior through both convection and radiation, the Discrete Ordinates (DO) radiation model is applied, alongside the Species Transport model to capture the combustion process occurring within the chamber.The burner operates by spraying fuel through a dedicated jet inlet into the chamber, while air enters symmetrically from four directions, combining with the fuel to sustain the flame. The chamber's internal flow path is cyclic — part of the gas exits through the exhaust section, while the remainder recirculates back into the enclosure along the same circular path.Several assumptions were applied to the simulation: it was run under steady-state conditions using a pressure-based solver, with gravitational effects excluded.Geometry & MeshThe 3D geometry was designed in Design Modeler. Given the model's symmetrical structure, only a 90-degree section was modeled, with the two lateral surfaces defined as symmetry boundaries. The geometry consists of three small-diameter inlet ducts (two air inlets and one fuel inlet) and one small-diameter exhaust outlet pipe.The domain was meshed in ANSYS Meshing using an unstructured grid totaling 1,107,286 elements, with boundary layer mesh applied at the inlet and outlet sections to improve the accuracy of near-wall flow behavior.MethodologyKey simulation settings included:Viscous model: Realizable k-epsilon with enhanced wall treatmentSpecies model: Non-premixed combustionRadiation model: Discrete Ordinates (DO), with the energy equation enabledBoundary conditions: Velocity inlets for air (2 m/s, 300 K) and fuel (1 m/s, 300 K), each with internal emissivity of 1, zero NO pollutant mass fraction, and mixture fraction settings appropriate to each stream (fuel set to a mean mixture fraction of 1); pressure outlet at the exhaust (0 Pa gauge, internal emissivity of 1); outer walls set to zero heat flux with opaque boundary type and internal emissivity of 1Solution methods: Coupled pressure-velocity coupling, PRESTO! for pressure discretization, and second-order upwind schemes applied across momentum, energy, turbulent kinetic energy, turbulent dissipation rate, pollutant NO, discrete ordinates, mean mixture fraction, and mixture fraction varianceInitialization: Hybrid methodConclusionThe simulation captures the combustion behavior within the bluff-body mild burner, characterizing how the cyclic recirculating flow pattern sustains flame stability while combining radiation and convective heat transfer mechanisms to distribute thermal energy throughout the chamber. The resulting flow, temperature, and species distribution fields reflect the coupled effects of the non-premixed combustion process and the recirculating exhaust pathway central to this burner's mild combustion design.

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.

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.

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

Diesel Fuel Combustion: Particle Surface Reaction CFD SimulationDescriptionDiesel spray combustion involves complex multiphase interactions, including liquid fuel atomization, vaporization, turbulent mixing, and chemical reaction. This study uses a Discrete Phase Model (DPM) to simulate diesel spray combustion, tracking how diesel fuel droplets evaporate, react with oxygen, and generate combustion products. The simulation considers a multi-component diesel mixture composed primarily of gasoil and water (H₂O), injected into an oxidizing environment containing O₂, with the resulting reaction producing CO₂ and H₂O vapor.The primary objective is to analyze the behavior of the reacting spray, track the spatial distribution of species such as CO₂ and H₂O vapor, and evaluate how evaporation and reaction kinetics influence overall combustion efficiency. The study combines finite-rate chemistry with the eddy-dissipation model to capture both kinetically-controlled and turbulence-driven reaction dynamics, offering insight into the spatial distribution of combustion products that can help optimize diesel combustion for efficiency and emissions control.ANSYS Fluent solves this reacting multiphase flow using an Eulerian-Lagrangian approach: the continuous gas phase is modeled through the Navier-Stokes equations coupled with turbulence and combustion models, while the discrete diesel droplet phase is tracked using the Lagrangian framework. The geometry of the diesel injector and combustion chamber was built in SpaceClaim to accurately capture the nozzle and spray region, and the mesh was generated in ANSYS Meshing with refinement concentrated near the injector nozzle to resolve the high velocity and pressure gradients occurring there. The final mesh totals 1,250,256 cells, balancing computational accuracy with efficiency.MethodologyDiesel droplets were injected and tracked as discrete particles using the Discrete Phase Model, undergoing evaporation and chemical reaction as they traveled through the domain. Since the fuel was modeled as a mixture of gasoil and water, multicomponent evaporation was applied: water evaporates first due to its lower boiling point, while the gasoil component undergoes thermal decomposition and combustion afterward.Combustion itself was captured using a combined finite-rate/eddy-dissipation approach, accounting for both kinetically-controlled and turbulence-driven reaction behavior to ensure realistic predictions within the turbulent flow field. The Species Transport model solved the transport equations for the reacting species (O₂, CO₂, H₂O vapor) to determine their spatial distribution, while turbulence was resolved using the standard k-epsilon model.ConclusionThe results include contour plots of the key combustion products and particle behavior throughout the domain. The CO₂ distribution highlights the regions where combustion is occurring and reflects the efficiency of the oxidation reactions taking place, while the liquid water distribution indicates areas of incomplete evaporation or residual water content remaining in the fuel. The H₂O vapor distribution, by contrast, shows the extent of evaporation and combustion product formation across the domain.Particle diameter distribution shows diesel droplets shrinking as evaporation and combustion progress, with larger droplets persisting in cooler, lower-turbulence regions, while particle temperature profiles show droplet temperatures rising as they move through the combustion zone, peaking near regions of the most intense oxidation activity. Together, these results characterize the spray combustion process in detail and highlight opportunities for optimizing fuel-air mixing and overall combustion efficiency.

Rosseland Radiation Model, Combustion of Train in TunnelDescriptionThis project simulates the combustion of a train within a tunnel environment using ANSYS Fluent, focusing on the resulting radiation heat transfer captured through the Rosseland radiation model — a method specifically suited to optically thick media such as the dense combustion products generated in this confined-space fire scenario.The 3D geometry represents the tunnel interior with the train positioned inside, meshed using an unstructured grid totaling 372,705 cells.MethodologyCombustion was modeled using the Species Transport model with a volume-based reaction definition representing diesel-air combustion. Radiation heat transfer was captured using the Rosseland approximation, a simplified form derived from the P-1 radiation model that becomes appropriate once the optical thickness of the medium exceeds approximately 3 — a condition well-suited to the soot- and combustion-product-laden atmosphere generated by a train fire within an enclosed tunnel.Boundary conditions were configured to represent fuel leakage and its interaction with the surrounding air, coupling the combustion source with the broader tunnel airflow.ConclusionResults include detailed contours of temperature distribution, velocity fields, radiative heat flux, and mass fractions of fuel, carbon dioxide, oxygen, and water vapor. Together, these results characterize how combustion and radiation heat transfer interact within the confined tunnel geometry, illustrating how the Rosseland approximation captures radiative heat exchange through the optically thick combustion products generated by the fire.These results are directly relevant to tunnel and railway fire safety assessments, offering insight into thermal and radiative conditions during a train fire event that can inform tunnel safety design, ventilation strategy, and emergency response planning.

Jet Fan Application in a Tunnel Considering a Car Explosion, CFD Simulation ANSYS FluentDescriptionThis project simulates a car explosion within a tunnel using ANSYS Fluent, modeling a scenario where a car ignites due to a gasoline leak combined with airflow contact while crossing through the tunnel's interior. The resulting explosion ignites a fire and releases carbon dioxide into the enclosed tunnel space, where the gas accumulates and cannot disperse into open air, posing a serious hazard to other vehicles and passing pedestrians. To address this, tunnels are equipped with jet fans mounted on the roof, which draw carbon dioxide and other pollutants upward and expel them outward, serving as the primary defense against dangerous gas buildup during such an event.The 3D geometry was designed in SpaceClaim, representing the interior of a tunnel with a car modeled on the floor and a jet fan mounted on the roof. A specific volume at the car's rear was defined as the explosion source, alongside a designated region at the jet fan's inlet representing the fan itself. The domain was meshed in ANSYS Meshing using an unstructured grid totaling approximately 2,700,000 cells.MethodologyThis model assumes the combustion reaction has already occurred, so rather than modeling combustion itself, the simulation focuses solely on the resulting carbon dioxide emission. The Species Transport model was used to define the air and CO2 species, with airflow entering the tunnel at 300 K and 1.5 m/s. At the explosion source volume, a CO2 emission rate of 10,000 kg/m³·s and a thermal energy source of 1000 W/m³ were defined to represent the combustion byproducts. The jet fan itself was modeled using a fan boundary condition with a pressure jump of 1,000,000 Pa, which drives the surrounding air to be drawn into and expelled through the fan.Several assumptions were applied throughout: a pressure-based solver was used, the simulation was run under steady-state conditions, and gravitational effects were excluded.ConclusionResults include 2D and 3D contours of pressure, velocity, temperature, and the mass fractions of air and CO2. The results confirm that the jet fan system functions as intended — the explosion at the car's rear generates significant heat and releases CO2, which is then drawn upward and extracted through the jet fans, effectively preventing the gas from spreading throughout the tunnel's interior.To evaluate the jet fan's performance more rigorously, the simulation was repeated under identical conditions but with the fan boundary condition removed from the jet fan inlet. Without the jet fan operating, the results show CO2 filling the tunnel's interior unchecked, underscoring the jet fan system's critical role in maintaining a safe environment during a tunnel fire event.