Moving Reference Frame (MRF) – ANSYS Fluent Training Package, 10 Practical Exercises for ADVANCEDS

Description

Moving Reference Frame (MRF) CFD Simulation Package, ANSYS Fluent Training for ADVANCED Users

This CFD training package is prepared for ADVANCED users of ANSYS Fluent software in the Moving Reference Frame (Frame Motion) area, including 10 practical exercises. You will learn and obtain comprehensive training on how to simulate projects. The achieved knowledge will enable you to choose the most appropriate modeling approaches and methods for applications and CFD simulations.

Cavitation (Moving Reference Frame)

The cavitation phenomenon is one of the phenomena in that vapor bubbles are formed in the part of the fluid whose pressure is low. Sometimes there is a misconception that the only reason for this phenomenon to occur and the formation of steam bubbles is because the liquid pressure reaches the vapor pressure (P_v). However, various other factors and parameters cause this phenomenon to occur. In project number 1, the fluid flow of water and the cavitation phenomenon around an Inducer inside a pipe.

One of the most critical industry issues is investigating the possibility of cavitation inside the pumps and solutions to reduce it. So in project number 2, fluid is defined as diesel vapor with a density equal to 9.4 kg.m-3 and a viscosity equal to 0.000007, and also the multiphase VOF model is used. Thus, the base fluid of diesel is liquid, and the secondary fluid is vapor diesel, and between these two fluids, a mass transfer is defined in the form of cavitation.

In project number 3, which has been done by the CFD numerical simulation method, cavitation has been simulated in a cross-flow turbine. Unlike most turbines where the flow is axial or radial, the fluid flows crosswise. This type of turbine has a low speed and is used for places where a low head and high flow are required. This project has been done in three main parts. In the first case, which is without an airfoil, but in the second case, to prevent cavitation, an airfoil is placed at the entrance, and in the third case, the airfoil angle compared to the second case is 15 degrees in a clockwise direction.

Compressor

Project number 4 simulates the air compression inside a Rampressor. The Rampressor is a unique ultrasonic compressor rotor that operates at a high-pressure ratio, and engine technology and gas compression are the ramjet ultrasonic shock wave. In this simulation, the inner wall of the Rampressor rotates around its central axis (z-axis) at a rotational speed of 40,000 rpm.

Turbine

In project number 5, the effect of steady rotation of centrifugal turbine on water and two-phase air mixture is investigated. The multiphase MIXTURE model is used to solve water and air phases interactions. The secondary phase (air) volume fraction has very low values in the 0.0001 order, which proves the validity of the mixture multiphase model in this project. The secondary phase volume fraction should be less than 15% for applying the Mixture Multiphase model. Slip Velocity has been considered at the water and air contact interface.

Fan Stage

In project number 6, steady airflow in a 3D geometry of the Fan Stage is simulated. A fan stage is a common apparatus used to create steady airflow in industrial applications used in the cooling process of newly painted body parts. The periodic boundary condition simulates the real fan stage at the lowest computational cost. Two sections are involved Rotor and Stator. The rotor, which has a built-in blade, rotates with constant angular velocity and leads air to enter the stator region with high velocity. Blade with-in stator alters the flow direction to force the exit stator approximately normal to the outlet surface. Rotor domain rotation is simulated using an MRF module with an angular velocity equal to 1800rpm.

Rice Dryer (Moving Reference Frame)

In project number 7, a revolving rice dryer device was simulated using Evaporating droplets with a one-way DPM model, and then the results were investigated. Hot air enters the rice dryer through the holes on a Porous tube located at the center of the enormous chamber. About three million rice particles are injected with 15% moisture droplets into a chamber revolving with 100rpm angular speed.

Sloshing

Project number 8 shows the importance of the effect of fluid sloshing within the tank on the maneuverability of floating devices like ships, boats, and so on. The initial stage of any simulation is devoted to designing solution geometry or computational domain modeling. The tank uses several series of joints and inner walls to prevent fluid movement. The model of the 2-D tank is modeled by Design Modeler software. The tank geometry is 1 m long and 0.7 m wide. Six rows of 0.35 m high and 0.04 m thick separated the fluid layers.

Earthquake

Project number 9 simulates the effect of an earthquake on a dam. A computational area is designed around a dam with water and air currents. Therefore, a multiphase model of VOF (volume of fluid) has been used to define two air and water flows. Since the interface boundary of the two air and water currents is recognizable and the two fluids do not mix, the multiphase VOF model is used. Using Region Production and the PATCH tool, water flow can be separated from the initial airflow Frame Motion technique to define the earthquake process using a UDF to determine the type of movement and displacement of the computational domain.

Acoustic (Moving Reference Frame)

Project number 10 simulates the airflow inside a Turbojet and examines the acoustic wave and the sound produced inside this turbojet. The model includes a turbojet that has a fan in its inlet. This fan rotates at 2000 rpm and around the X-axis in the current model. Therefore, an airflow area is defined around the fan, which is modeled using frame motion. This turbojet is moving in the air with a Mach number of 0.5, which indicates that the flow can be considered compressible; Because the value of Mach number is more than 0.3. The Broadband Noise Sources model is also used to define the acoustic model. Definitive density is equivalent to air density, i.e., 1.225 kg.m-3, sound speed is equivalent to sound speed in the air, i.e., 340 m.s-1, and reference acoustic power is equal to 1e-12.

You can obtain Geometry & Mesh file and a comprehensive Training Movie that presents how to solve the problem and extract all desired results.