Unconfined Pool Boiling, ANSYS Fluent TutorialDescriptionThis project simulates unconfined pool boiling of saturated water inside a cylindrical chamber using the Eulerian multiphase model in ANSYS Fluent. Pool boiling is a fundamental heat transfer process across many industrial and engineering applications, and understanding its behavior — including key concepts like the Onset of Nucleate Boiling (ONB), Departure from Nucleate Boiling (DNB), and Critical Heat Flux (CHF) — is essential for designing efficient heat exchange systems, preventing equipment burnout, and ensuring safety in high-heat applications such as nuclear reactors.The cylindrical chamber geometry was designed in Design Modeler and meshed in ANSYS Meshing using a structured grid, with mesh quality specifically optimized to capture the complex interphase behavior characteristic of multiphase boiling simulations.MethodologyLiquid water and vapor interaction was captured using the Eulerian multiphase model, with the RPI (Rensselaer Polytechnic Institute) boiling sub-model enabled to represent the underlying boiling physics. Several interphase forces were configured, including drag, lift, and wall lubrication, alongside wall adhesion to realistically capture bubble detachment behavior from the heated surface.Boiling mass transfer mechanisms were activated to capture the liquid-to-vapor phase change directly, with the energy equation enabled to resolve the resulting temperature distribution and the Realizable k-epsilon model applied for turbulence. Bubble dynamics were modeled in detail, including bubble departure diameter and frequency, nucleation site density, an area influence coefficient, and a quenching model correction incorporating bubble waiting time — together capturing the full cycle of bubble formation, growth, and departure from the heated wall.ConclusionResults include vapor volume fraction contours that reveal the bubbles' changing shape and the mass exchange occurring through condensation as they ascend through the liquid, along with the convective motion this boiling process induces throughout the surrounding fluid.These results illustrate the complete physical picture of nucleate pool boiling — from bubble nucleation at the heated wall, through growth and departure, to condensation and convective mixing as bubbles rise — providing insight directly applicable to heat exchanger design optimization and to predicting the onset of burnout conditions in high-heat industrial and safety-critical applications.

Heat Pipe (Thermosyphon) CFD Simulation Using VOF Multiphase Model, ANSYS Fluent TrainingDescriptionThis project simulates a heat pipe using the multiphase VOF model in ANSYS Fluent. The 3D geometry was designed in Design Modeler as a rectangular domain measuring 10 cm long and 1.2 cm wide, meshed in ANSYS Meshing with a total of 18,000 cells. Given the nature of this problem, a transient solver was used throughout.MethodologyThis study models the heat pipe's operation using the multiphase VOF model, with evaporation and condensation mass transfer explicitly activated to capture the phase-change cycle central to the device's function. A hot wall was set at 400 K and a cold surface at 300 K, and solving the problem in a time-dependent manner revealed water droplets forming at the top of the geometry and moving downward under the combined influence of capillary action and gravity. The saturation property was defined using a piecewise linear input, with turbulence resolved using the Realizable k-epsilon model.ConclusionResults include 2D contours of water and vapor volume fraction, mass transfer rate, and temperature. Comparing volume fraction contours at two different time points clearly shows an established, repeating evaporation-condensation cycle, with droplets forming at the top of the tube and migrating downward under gravity and wall capillary effects.The results also capture the vapor phase's density variation over time, following the ideal gas law as local temperature and pressure conditions shift. The mass transfer rate itself trends toward a stable average value, indicating that evaporation and condensation reach a balanced, self-sustaining equilibrium within the heat pipe — consistent with the expected steady-cycling behavior of a properly functioning thermosyphon.

DescriptionThis project uses ANSYS Fluent to simulate boat propeller cavitation, applying the Mixture multiphase model to a critical phenomenon in marine propulsion engineering. Cavitation occurs when localized low pressure on the propeller blades causes water to vaporize, forming bubbles that collapse and erode blade surfaces while degrading propulsion efficiency. This simulation captures how cavitation forms and evolves around a rotating propeller, a key concern in naval architecture and propeller design.MethodologyThe propeller geometry is built in DesignModeler and meshed in ANSYS Meshing using an unstructured grid suited to the rotating fluid domain. The Mixture model is configured with the Schnerr-Sauer cavitation model to simulate water-vapor phase change, with appropriate vaporization pressure limits set to capture cavitation onset. Mesh motion is implemented to represent propeller rotation, paired with the SST k-omega turbulence model for accurate external flow resolution, and the analysis is run transient to capture the time-dependent development of cavitation, including super-cavitation at high rotational speeds.ConclusionResults include vapor volume fraction distributions on the propeller surfaces, pressure fields showing where cavitation initiates and grows, and the relationship between rotational speed and cavitation extent. These findings directly inform propeller design optimization — blade geometry, material selection, and operating speed — to reduce cavitation-driven erosion, noise, and vibration, supporting more efficient and durable marine propulsion systems.

DescriptionThis project extends a previous simulation of the VA-111 Shkval supercavitating torpedo in ANSYS Fluent by incorporating mass transfer to capture cavitation effects. The objective is to analyze how cavitation influences the vehicle's hydrodynamic performance and to compare it against the non-cavitating case. The Shkval is a high-speed underwater vehicle, making this a distinctly marine and naval engineering problem, where supercavitation is exploited to dramatically reduce drag and enable exceptional underwater speeds.The geometry and mesh remain the same as in the previous study: the VA-111 Shkval was created in SpaceClaim and meshed in Fluent Meshing, producing a polyhedral mesh of 257,000 cells.MethodologyThe simulation uses a transient, pressure-based solver with the k-ε turbulence model, initialized from a steady, no-mass-transfer case. To capture the cavitation, the Zwart-Gerber-Belamri model is enabled, which accounts for the mass transfer between the liquid and vapor phases. This cavitation model is coupled with the VOF multiphase model to accurately represent the formation and collapse of the vapor cavities that surround the vehicle.ConclusionThe results reveal significant differences in the flow field and performance characteristics once cavitation is taken into account. The mass transfer rate contour identifies the regions where cavitation occurs, with the highest rates near the vehicle's nose and along its body. The volume fraction contour shows the vapor cavities enveloping the vehicle, which effectively reduce the wetted area.The pressure distribution exhibits a low-pressure region near the nose that triggers the formation of the vapor cavities, and the velocity magnitude contour shows higher velocities within the cavity than in the surrounding liquid — confirming the drag-reduction mechanism of supercavitation. The turbulent kinetic energy contour highlights elevated turbulence in the wake, caused by the collapse of the vapor cavities; this turbulence can add to the drag and affect the vehicle's stability.Overall, incorporating mass transfer and cavitation modeling provides valuable insight into how cavitation shapes the hydrodynamic performance of the VA-111 Shkval. The results clearly demonstrate the benefits of supercavitation: by forming vapor cavities that shrink the wetted area, the vehicle achieves a marked reduction in skin-friction drag — the key principle behind high-speed underwater travel in marine engineering.

Sub-Oceanic Volcanic Activity — ANSYS Fluent CFD SimulationDescriptionThis project simulates sub-oceanic volcanic activity using ANSYS Fluent and the Volume of Fluid (VOF) multiphase model — a complex and critical environmental scenario. Sub-oceanic volcanic eruptions play a crucial role in shaping the planet's oceans and climate, and their accurate simulation supports oceanographic research, ocean engineering, tsunami forecasting, and weather and climate science. The simulation captures the interaction between water, lava, and vapor on the sea floor, combining wave modeling with the extreme thermal effects of an eruption. As the capstone of the Open Channel Flow: Beginner CFD Training Package, it is the most complex and specialized case in the set, bringing together free-surface waves, multiphase interaction, and mass transfer in a single environmental problem.MethodologyThe underwater topography is designed in ANSYS Design Modeler and meshed in ANSYS Meshing with an unstructured grid optimized for a challenging multiphase scenario. The VOF multiphase model is configured to capture the interaction between water, lava, and vapor. The Open Channel Flow model is enabled together with the Open Channel Wave boundary submodel for realistic wave simulation, and Fifth-Order Stokes Wave Theory is implemented for accurate surface-wave patterns. Mass transfer is modeled using the Lee model to represent evaporation and condensation — capturing the vapor generation caused by the extreme eruption temperatures and its effect on the ocean hydrodynamics.AnalysisPost-processing focuses on the interaction between the eruption and the sea surface: the disruption of the wave patterns due to the volcanic activity, and the hydrodynamic effects of vapor generation on the ocean surface dynamics. From these results you can interpret the complex multiphase behavior, validate the model against known oceanic and volcanic phenomena, and connect the findings to real-world applications such as tsunami prediction, ocean engineering, and climate research. By the end of this project, you'll be able to set up a VOF simulation coupling water, lava, and vapor, apply the open-channel wave submodel with Fifth-Order Stokes wave theory, implement evaporation and condensation with the Lee mass-transfer model, and interpret the wave–eruption interaction that governs this environmental scenario.

Home Water Distiller CFD SimulationDescriptionThis project simulates a small-scale home water distiller using ANSYS Fluent, investigating one of the more accessible approaches to water desalination. The system relies entirely on heat transfer and phase change to produce clean water: a floor heater warms water until it evaporates, and because this steam carries none of the original salt, bacteria, or contaminants, cooling it back into liquid form yields pure freshwater. The steam travels through a spiral tube, where a fan cools the surrounding pipe walls, driving the vapor to condense back into fresh water on the other side.The device is built from three functional sections: an evaporator at the bottom where water turns to steam, a condenser at the top where that steam is cooled, and a spiral tube connecting the two that serves as the pathway for vapor transfer and the site where condensation actually occurs. To keep the model manageable, the heater and fan themselves weren't explicitly modeled; instead, fixed temperatures were assigned directly to represent their effects; the evaporator was held at 373 K, matching the saturation temperature of water, while the condenser was set to 363 K. The patch tool was used to define the initial water level inside the evaporator tank.Because the process unfolds over time as water evaporates and vapor condenses, the simulation was run as a time-dependent, unsteady case, allowing the rate of phase change and the resulting freshwater output to be tracked as the system evolves. The three-dimensional geometry was built in Design Modeler, and the model was meshed in ANSYS Meshing using an unstructured grid of 478,805 cells.MethodologyThree phases coexist in this system: liquid water, water vapor, and air, which serves as the coolant inside the condenser. Since these phases need to be tracked with distinct, clearly defined boundaries, the Volume of Fluid (VOF) model was used, with air set as the primary phase and both liquid water and water vapor treated as secondary phases. The Sharp interface option was applied to keep the boundary between phases crisp rather than smeared across a transition layer.The evaporation-condensation process between the water and vapor phases was captured through a mass transfer mechanism based on Lee's equations, which calculate phase-change rates based on the saturation temperature and the evaporation/condensation frequency coefficients. With the saturation temperature set at 373.15 K, any fluid temperature above this threshold triggers evaporation, while any temperature below it triggers condensation.ConclusionThe simulation produced contours of temperature, phase-change rate, and volume fraction for both water and vapor, captured on a mid-plane cross-section at the final second of the 10-second simulation, along with animations tracking how these quantities evolve over time. Plots of freshwater output — both the volume-averaged water fraction inside the system and the mass flow rate of freshwater leaving the condenser — were also generated.The temperature and mass transfer contours line up closely: wherever the fluid temperature drops below the saturation point, condensation occurs, shown by a negative phase-change rate. Inside the evaporator, water evaporates from its surface and rises as steam; once that steam reaches the cooler condenser tube, it condenses back into liquid, producing usable freshwater. The output plots confirm that freshwater production increases steadily over time as more condensation occurs, demonstrating that the desalination system's core evaporation-condensation cycle works as intended.

DescriptionThis project simulates air gap membrane distillation (AGMD) using ANSYS Fluent. Producing potable water from saline or impure sources is a central goal of clean water engineering, and AGMD is one of the membrane distillation technologies developed specifically for this purpose.Water desalination systems fall into two broad categories: thermal desalination and membrane desalination. In the thermal method, a phase change is used to produce fresh water, whereas in the membrane method, specialized membranes separate the water from its impurities. Membrane distillation (MD) systems combine the two approaches — they rely on both a phase change and a dedicated filter membrane. Several MD configurations exist; the one studied here is Air Gap Membrane Distillation (AGMD).The AGMD system consists of four zones: the feed channel, the membrane layer, the air gap, and the cooling channel. Hot water flows through the feed layer while cold water flows in the opposite direction through the cooling layer. The membrane layer sits next to the feed water, and the air gap is placed between the membrane and the cooling channel. In operation, the water first undergoes surface evaporation, and the resulting pure vapor then condenses on the cold surface. For simplicity, the hot feed water is assumed to have already been converted to steam, so saturated steam flows through the feed channel, ready to condense in the air gap.The geometry was modeled in 2D using Design Modeler, and the model was meshed in ANSYS Meshing using a structured grid of 150,000 cells.MethodologyBecause the system involves the steam turning into water through condensation, together with the presence of an air gap, three phases must be represented, so a multiphase model is required rather than a single fluid. The VOF (Volume of Fluid) model is used, since it cleanly separates the different phases and resolves a distinct interface between them — the best choice for capturing a sharp boundary between the water and vapor phases. Air is defined as the primary phase, with liquid water and water vapor as the secondary phases; the volume fraction of each secondary phase is solved through its transport equation.A phase change occurs between the water and vapor phases, so a mass transfer is defined between them based on the evaporation-condensation mechanism. This mechanism governs the phase change between liquid and vapor, with Lee's equations used to calculate the mass transfer rate; these equations depend on the saturation temperature and the frequency coefficients of evaporation and condensation. In addition, the membrane is represented as a porous medium, with a porosity parameter — the ratio of void volume to total volume — defining its permeability.ConclusionOn completion of the solution, contours of temperature, the phase change rate between water and vapor, and the volume fraction of each of the water and vapor phases were obtained.The results show the temperature dropping on the cold side of the air gap, with the temperature contours clearly revealing the thermal boundary layer. The highest condensation (phase change) rate occurs in the regions where the temperature falls, and the negative sign of the phase change rate indicates the transformation from vapor to liquid. Examining the volume fraction contour of the distilled water reveals a film of liquid forming on the cold plate of the air gap; this freshly produced fresh water then runs to the bottom of the air gap under gravity.Overall, the results confirm that the desalination system operates correctly and that the membrane distillation mechanism performs as intended — demonstrating how AGMD converts hot saline feed into clean, condensed fresh water, and how CFD can be used to evaluate and optimize such clean-water technologies.

DescriptionThis project simulates a Humidification Dehumidification (HDH) desalination system using ANSYS Fluent, a core clean water engineering method for producing fresh water from saline sources. The system operates in two coupled stages: a humidifier (evaporator), where hot salt water is sprayed and evaporates into dry air to produce salt-free humid air, and a dehumidifier (condenser), where that humid air contacts cold tube surfaces and condenses into fresh water. This two-step cycle mirrors real-world HDH desalination units, making it directly relevant to sustainable, low-energy freshwater production.MethodologyThe system is modeled in two separate simulations reflecting its two stages. The 3D geometry is built in DesignModeler and meshed in ANSYS Meshing — a hybrid structured/unstructured mesh of 206,928 cells for the humidification chamber, and an unstructured mesh of 553,086 cells for the dehumidification chamber. Cooling tubes in the dehumidifier are simplified using a constant-temperature thermal wall boundary rather than explicit pipe modeling.In the humidification simulation, salt water is introduced as a discrete phase using the Discrete Phase Model, with droplets (1e-6 m diameter) surface-injected over 10 seconds and evaporating into the dry air stream. The Species Transport model tracks the resulting water vapor concentration without chemical reaction, and the internal membrane packing is represented as a porous medium defined by porosity, viscous resistance, and inertial resistance.In the dehumidification simulation, the VOF multiphase model captures the distinct liquid water and water vapor phases, with evaporation-condensation mass transfer defined via Lee's equations based on saturation temperature and phase-change frequency.ConclusionThe humidification stage results, evaluated at the final simulation second, show water vapor mass fraction and discrete particle concentration contours, along with animations tracking droplet spray behavior and vapor mass fraction buildup over time — confirming steady production of humid, salt-free air. The dehumidification stage results show velocity, temperature, mass transfer rate, and phase volume fraction contours, confirming condensation occurring in regions where vapor temperature drops below saturation near the cold tube surfaces, with the highest freshwater yield concentrated around those cooled surfaces. Together, these results validate the HDH system's core function: converting saline water into clean, potable water through a fully coupled evaporation-condensation cycle.

DescriptionThis project simulates a two-stage water desalination device, a system that purifies water through evaporation and condensation rather than filtration, removing even the smallest contaminants that other methods can miss. Water is heated to promote surface evaporation at the bottom of the device, and the resulting vapor rises and contacts cooler sloped surfaces where it condenses back into pure liquid water, directed toward the system outlet. The geometry is built in Design Modeler and meshed in ANSYS Meshing with an unstructured grid of 1,936,581 elements.MethodologyThe VOF multiphase model captures the liquid-vapor interface inside the desalination trays, and since surface evaporation isn't included in Fluent's base solver, a UDF is hooked into the source code to model this mass transfer mechanism directly. The device's bottom surface raises the bulk water temperature to around 353 K, increasing the water molecules' energy and accelerating the evaporation process. Turbulence is resolved with the realizable k-epsilon model, chosen for its accuracy in internal flows, and the energy equation is active given the heat transfer driving the process. The simulation runs transient and in 3D, with gravity enabled so the vapor's upward motion, a consequence of its lower density relative to liquid water, is captured correctly.AnalysisThe results show a stratified pressure distribution inside the system trays, consistent with the hydrostatic pressure of the standing water column in each tray. The temperature contour confirms elevated temperatures at the bottom surface, which increases the water molecules' motion and kinetic energy and in turn speeds up surface evaporation. The mass transfer rate contour quantifies how much vapor is generated at any point in the system, and this vapor generation rate matches the amount of water ultimately condensed at the cool sloped plates and collected as distillate, confirming that the vapor produced through evaporation is fully accounted for as clean water leaving through the outlet.

DescriptionThis project investigates the performance of a step solar desalination unit (solar still) using ANSYS Fluent, studied through CFD analysis. Producing potable water from saline sources is a central goal of clean water engineering, and the solar still achieves this passively — using nothing but solar energy to convert brackish or seawater into fresh water.The model consists of a small chamber with a sloping glass surface on each side and a series of steps inside, over which saline water flows. Solar radiation passes through the glass to the water surface on the steps, evaporating it; the resulting vapor then meets the cold glass surface and condenses in a distillation process. The freshwater produced by condensation runs down the slope of the glass plate and is discharged as pure water.The model was built in 3D using Design Modeler. Because the geometry is symmetric, only one-quarter of it is modeled. This quarter-geometry comprises two sloping glass surfaces and the steps that carry the water flow. Meshing was performed in ANSYS Meshing, producing 809,037 elements.MethodologyTo convert saline water into fresh water, the water must first be turned into vapor and then condensed back into liquid. A solar still typically consists of a sloped glass cover placed over the device and a stepped platform that holds the saline water to be distilled. The glass cover acts as both a rigid substrate and a transparent layer that admits the sun's rays, while the heat needed to generate vapor comes from the solar energy absorbed inside the device. The vapor then rises, strikes the cool glass cover, and condenses into fresh water.To capture this, the Solar Ray Tracing model is enabled to represent the absorbed solar heat, and the Species Transport model is activated to model the two components — water and vapor — inside the chamber. This approach treats the chamber interior as a water-vapor mixture and does not explicitly simulate the flow of the distilled water. At the start of the simulation, the interior is filled entirely with vapor; the bottom plane of the chamber represents the water surface, and since evaporation occurs there, this surface is treated as vapor.Constant values of 1.00314 × 10⁻⁵ m²/s and 0.0002 kg/m·s are assigned to the mass diffusion coefficient and the thermal diffusion coefficient, respectively, governing the conversion between water and vapor. The sloping plate where the vapor condenses is assumed to consist only of vapor. The ambient air temperature is taken as 311.75 K with a heat transfer coefficient of 25 W/m²K. The stepped platform holding the saline water is assumed to absorb heat with no transmissivity, while the glass cover is assumed to have maximum transmissivity and no absorbance. Gravity is enabled in the Y direction, and the incompressible ideal-gas model is used to account for the density difference between water and vapor.ConclusionOn completion of the solution, three-dimensional contours of velocity, temperature, velocity vectors, and species mass fraction inside the still were obtained.The velocity contours and vectors show how the generated vapor rises within the device to strike the upper sloped glass surface. The 3D temperature contour makes clear that the saline water on the stepped platform has heated up enough to evaporate, while the glass cover remains cold enough to condense the vapor, which then slides down to the lower part of the device where the fresh water is collected. Finally, the species mass fraction contour shows a water mass fraction of one on the stepped platform and the glass substrate, while the water fraction decreases within the interior space — confirming that vapor is forming there. Together, these results demonstrate the complete evaporation-condensation cycle that enables the solar still to deliver clean, desalinated water using only solar energy.