Pigging Oil Flow in a Pipeline CFD Simulation
The present problem simulates the pigging oil flow inside pipelines using ANSYS Fluent software.
This ANSYS Fluent project includes CFD simulation files and a training movie.
There are some free products to check our service quality.
To order your ANSYS Fluent project (CFD simulation and training), contact our experts via [email protected], online support, or WhatsApp.
The present problem simulates the pigging oil flow inside pipelines using ANSYS Fluent software. Inside the pipelines in this model, there is a piece called a pig. The term pig stands for Pipeline Inspection Gauge and is used in pipelines to check and record geometric and fluid information, as well as other items such as cleaning pipes and creating a physical barrier between two different fluids, etc. In fact, using pigs inside pipelines and controlling and directing them is called pigging.
Since the presence of pigs in the passage of fluid flow can act as a barrier, the use of these pigs can cause a pressure drop in the flow of the desired fluid, which is known as a problem that must be addressed. In the present model, a simple stationary pig is defined inside a pipeline. The purpose of the present simulation is to investigate the behavior of the fluid around the body of this pig inside the pipe and also to investigate the pressure drop on both the upper and lower sides of the pig.
The simulation process is performed in two different modes; Thus, oil flow with different inlet speeds including 0.9 m/s and 1.9 m/s enters the interior of the pipeline. Also, the VOF multi phase model has been used to define the oil and gas materials in the pipelines, and two materials have been defined as gas-oil and petro in the present model. This simulation was performed in 90 seconds with a time step of 0.03 seconds.
Geometry & Mesh
The present model is designed in two dimensions using Design Modeler software. The model includes a pipeline with a certain geometry, which has a simple pig inside it. The following figure shows a view of the geometry.
The meshing of the present model has been done using ANSYS Meshing software. The mesh type is unstructured and the element number is 5789. The following figure shows an overview of the mesh.
Pigging CFD Simulation
To simulate the present model, several assumptions are considered:
- We perform a pressure-based solver.
- The simulation is transient; the amount of pressure drop changes on both the top and bottom sides of the pig has been investigated over time.
- The gravity effect on the fluid is ignored.
A summary of the defining steps of the problem and its solution is given in the following table:
|Multi phase Model||VOF|
|number of Eulerian phases||2 (gas-oil & petro)|
|Inlet 1||Velocity Inlet|
|velocity magnitude||variable (0.9 & 1.9 m.s-1)|
|volume fraction for petro||1|
|volume fraction for gas-oil||0|
|gauge pressure||0 pascal|
|Walls (walls of pipeline & walls of pig)||Wall|
|wall motion||stationary wall|
|momentum||second order upwind|
|turbulent kinetic energy||first order upwind|
|turbulent dissipation rate||first order upwind|
|gauge pressure||0 pascal|
|y-velocity||variable (0.9 & 1.9 m.s-1)|
|petro volume fraction||0|
At the end of the solution process, two-dimensional contours related to the pressure, velocity, and volume fraction of each of the phases defined in the model are obtained. All contours of both cases are obtained at the last second of the simulation process.
All files, including Geometry, Mesh, Case & Data, are available in Simulation File. By the way, Training File presents how to solve the problem and extract all desired results.