CFD Simulation of a Firearm Silencer
Hello, this is Ertan Taskin from Ozen Engineering, Inc. In this video, I'll be discussing the generic simulations of suppressors or silencers used in firearms. The products we will use in this presentation include:
- Workbench
- SpaceClaim
- CFX Solver
- CFD Post
Introduction to Silencer Applications and Technology
The concept of the silencer dates back to the early 1900s. The silencer, shown as part 11, is attached to the rifle, identified as part 10. As the bullet moves from right to left on the screen and exits the barrel, it passes through structures that absorb pressure, thereby diminishing sound.
CFD Simulation Setup
We will demonstrate a CFD calculation on a generic case using Workbench. The focus will be on the fluid dynamics rather than the structural components. The geometry includes:
- Air as the main fluid domain
- The suppressor as the solid domain
- The bullet
We will also demonstrate a reference case without a silencer for comparison.
Geometry and Meshing
In SpaceClaim, we consider one-tenth of the entire domain. The mesh is coarse for simplicity and speed, but a finer mesh is recommended for more accurate results.
CFX Pre-Processing
In the CFX Pre, we define the bullet as an immersed solid with a translational degree of freedom along the Z-axis. The inlet boundary condition uses a pressure curve, and the majority of the domain is set as an opening condition. Symmetry boundary conditions are applied to the side surfaces.
Pressure Curve Conditions
We have several options for defining pressure curves:
- Create an expression for a sinusoidal curve with a step function.
- Import data for the pressure curve, ensuring correct units for time and pressure.
Post-Processing and Results
After setting up the problem, we perform CFD calculations and proceed to post-processing. The animation shows how pressure builds up, the bullet moves, and how the silencer affects pressure waves and sound.
Comparison with and without Silencer
We compare pressure curves for cases with and without a silencer. The suppressor significantly reduces sound intensity, although the suppressor in this example is not optimized.
Conclusion
This video demonstrated generic simulations of firearm suppressors using ANSYS products like Workbench, SpaceClaim, CFX, and CFD Post. Thank you for watching.
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Hello, I am Ertan Taskin from Ozen Engineering. Today, I will be talking about CFD simulations of a firearm silencer. The products I will be using in this presentation are Workbench, SpaceClaim, CFX Solver, and CFD Post.
Before diving into the details of the CFD application, I would like to give you a brief introduction about silencer applications and technology.
The idea of a silencer, as shown in part 11, is attached to the rifle with ID number 10. When the bullet moves from right to left on the screen and after it leaves the barrel, it passes through certain structures where the pressure is absorbed, diminishing the sound.
In the next slide, I will show you the simulation of CFD calculations on a generic case. In this example, we will use Workbench. In Workbench, we have a geometry and a fluid component, as well as a structural component. Our focus for this video will be on the fluid side.
We will start with the geometry, which is open in SpaceClaim. There are multiple components already assigned, including the main fluid domain, the suppressor (solid domain), and the bullet. In this example, I will also demonstrate a reference case without a silencer.
We will create a long solid fluid with a base column and remove the access part. We will then fit and paste the column one and one. We will notice that we have extra geometry on the surface. We will remove this, as it is not needed for the reference case.
We will continue with the CFX Pre and set the problem. The bullet is defined and the rest of the domain has a coarse mesh for easy and fast calculations. The bullet is in the barrel area on the fluid portion of the barrel area and is defined as an immersed solid.
We have provided a pressure curve for the inlet boundary condition. After the silencer portion, the rest of the domain is set as the opening condition. The side surfaces are symmetry boundary conditions.
We have several options for the pressure curve conditions, including expressions and user functions. With these settings, we can perform the CFD calculations and then do the post-processing. We will demonstrate the post-processing with the animation screen.
The pressure builds up and after a while, the bullet starts to move. The first pressure wave passes through the silencer and then diminishes. The bullet continues to move and leaves the firearm.
We will collect the pressure data at a specific region of the domain right after the silencer and see how the pressure is changing throughout the calculation time. Now let us examine the same field with the no silencer option.
We will see how the bullet moves and how the pressure regions are developing. We will use this cross at the exit of the firearm to make a comparison. We will look at two different pressure curves, one with a more sudden pressure increase and drop, and the other with a more gradual change.
These curves may mimic different firearm conditions or types of firearms. Considering the first curve, we will compare the no suppressor versus suppressor cases and look at the pressure profiles. We will notice a significant difference.
We can calculate the sound intensity with a generic formula and then make a comparison in terms of decibels to see if the suppressor versus no suppressor makes sense.
In this video, we demonstrated generic simulations of a firearm silencer using ANSYS products such as Workbench, SpaceClaim, CFX, and CFD Post. Thank you for watching, and please subscribe to our channel. If you have any questions, please leave a comment, and I will try to answer them.
