Thruster not generating enough thrust

Project Support
1

If I’m honest, I just want to double check with someone that knows what they’re doing. See… I’m trying to simulate how much thrust I can generate with a 2cm wide “turbine” spinning at 50 000 RPM to create suction for a linetracing racing “robotracer” robot. My current objective is to create at least 1N of thrust force ideally 2N. However, no matter what I do, I get 0.1N of thrust. And because I’m new, I’m not sure if the problem is in my geometry or somewhere within the simulation.

Sorry and thanks in advance. My project (I think)

2

Hi there, and welcome to the SimScale forum!

Thanks for reaching out and sharing your project. It’s an interesting application, and it’s completely normal to have questions when you’re starting out. A tenfold difference between your expected and simulated thrust is indeed significant, and it usually points to something in the setup that needs a second look.

Since I am unable to view your project directly, I’d recommend a few general troubleshooting steps. This will help you pinpoint whether the issue is with your geometry or the simulation settings.

Geometry Checklist

A solid simulation starts with clean geometry. Here are a couple of things to verify:

Watertight Model: Ensure your geometry is a “watertight” solid with no gaps or interfering surfaces.
Rotating Zone: For a simulation involving rotating parts like your turbine, you’ll need a dedicated cylindrical volume around it to define the rotating region. Make sure this volume fully encloses the turbine.

Simulation Setup

This is often where small details can have a big impact. I recommend walking through this excellent Tutorial: Drone Simulation Using Rotating Zones. It covers a very similar type of analysis and is a great guide for checking your own setup.

Here are the key areas to pay close attention to, as detailed in the tutorial:

Rotating Zone (MRF): In the “Advanced Concepts” section of your simulation setup, you need to define a Moving Reference Frame (MRF) rotating zone. Double-check that you’ve assigned the correct rotational speed (50,000 RPM) and the correct axis of rotation.

Boundary Conditions: How you define the air around your turbine is crucial. The tutorial provides a good example of setting up an “Atmosphere” boundary condition.

Mesh: The mesh quality is very important for accuracy. Ensure you have a fine enough mesh around the turbine blades to capture the geometry and the flow physics accurately. The tutorial covers how to apply mesh refinements.

Result Control: To measure thrust, you’ll need to use the “Forces and moments” result control item and assign it to the surfaces of your turbine blades. This will calculate the pressure and viscous forces acting on the blades.

If you’ve gone through the tutorial and are still facing issues, let us know.

I hope this helps you get to the bottom of the issue. Keep us posted on your progress!