Summary of "Fluid Flow Simulation in Pipe with Sudden Enlargement || Minor Loss || Analysis of Flow Through Pipe"

Summary of "Fluid Flow Simulation in pipe with Sudden Enlargement || Minor Loss || Analysis of Flow Through pipe"

This video tutorial demonstrates how to perform a fluid flow simulation in a pipe featuring a sudden enlargement using ANSYS Workbench (2022 R1). The main focus is on modeling, meshing, setting boundary conditions, running the simulation, and visualizing results to understand fluid behavior and minor losses due to sudden enlargement in pipes.

Main Ideas and Concepts

Objective: Simulate fluid flow through a pipe with a sudden enlargement to analyze velocity changes and flow behavior.
Software Used: ANSYS Workbench 2022 R1 (or any installed version).
Physical Setup: A pipe consisting of a smaller diameter section followed by a larger diameter section (sudden enlargement).
Fluid: water (default material selected).

Detailed Methodology and Instructions

1. Starting the Project in ANSYS Workbench

Open ANSYS Workbench and select the Analysis System.
Choose Design Modeler for geometry creation.

2. Geometry Creation

Set units to centimeters.
Create primitive cylinders to represent pipe sections:
- First cylinder: larger diameter, oriented along the x-axis.
- Second cylinder: smaller diameter, also oriented along the x-axis but positioned to create a sudden enlargement.
Use Boolean operations (unite) to combine the two cylinders into a single solid geometry.
Convert the solid pipe into a hollow section by applying Thin Surface:
- Select faces to keep.
- Set wall thickness (example: 0.5 cm).
Fill internal faces to define fluid volume inside the pipe.

3. Naming and Defining Zones

Rename fluid zone inside the pipe as "water".
Rename pipe walls as "pipe Wall".

4. Meshing

Generate default mesh initially to reduce computational time.
Specify boundary faces:
- Inlet face.
- Outlet face.
- Wall faces (pipe walls).
Mesh is transferable to Fluent for simulation.

5. Setup in Fluent

Define number of processes (e.g., 4) for parallel computation.
Specify gravity direction (usually y-direction, -9.81 m/s²).
Select fluid material as water.
Apply boundary conditions:
- Velocity inlet (e.g., 1 m/s).
- Outlet and wall boundary conditions set accordingly.
Initialize the flow with standard initialization from the inlet.

6. Calculation Settings

Set number of iterations (e.g., 20 for short runs, 500 for detailed runs).
Choose visualization parameters:
- Velocity contours.
- Streamlines.
- Wall shear or pipe wall parameters.
Run the simulation.

7. Visualization and Post-Processing

Adjust transparency of pipe walls for better visualization.
Create streamlines starting from the inlet to observe flow paths.
Modify legend and color scales for velocity contours.
Animate the flow to observe fluid particle movement through the sudden enlargement.
Save animations as video files for review.

Key Observations from Simulation

Velocity decreases significantly as fluid passes from the smaller diameter pipe section to the larger diameter section (sudden enlargement).
Fluid particles near pipe walls experience more resistance and move slower compared to particles near the pipe center.
Particles at the center exhibit higher velocity and move ahead of those near the walls.
Color contours and velocity streamlines visually depict these velocity variations.
The simulation runs until all fluid particles exit the outlet, providing a dynamic view of flow behavior.

Lessons and Applications

Sudden enlargement in pipes causes velocity drop and minor losses due to flow separation and resistance near walls.
CFD simulations help visualize and quantify these effects.
The methodology can be applied to other pipe geometries and fittings to analyze fluid behavior.
Proper geometry preparation, meshing, and boundary condition setup are crucial for accurate simulation results.