Advanced Manufacturing

Manufacturing Methods for a Better Engine:

Researcher Finds Rotating Detonation Patterns

Before you can begin to talk about the manufacturing methods for better engines, you need to learn what’s going on inside the machinery and investigate the physics. By building a series of experimental rotating detonation engines, University of Washington researcher James Koch and his team found promising patterns in an advanced technology known as the rotating detonation engine, or RDE.

A Tech Briefs Q&A reveals Koch’s test engines and how those experimental manufacturing methods confirmed the researcher’s mathematical models of the “explosive” RDE.

Testing the Model: The Manufacturing Methods of an Experimental Rotating Detonation Engine

The "RDE" is a promising technology, because of its high power output and simple manufacturing method: place a cylinder inside of a cylinder.

But don’t be fooled by the simple structure.

With a rotating detonation engine, fuel flows in the gap between the cylinders. Upon ignition, the rapid heat release forms a strong pulse of gas, and the detonation wave travels around the circular channel, or annulus, creating a wave of pressure.

A rotating detonation engine has a shocking combustion process, and these explosive detonations have been traditionally difficult to model.

"These detonations have a mind of their own," said Koch. “Once you detonate something, it just goes. It's so violent.

Using high-speed cameras, the team, led by Koch, demonstrated characteristics of the engine’s explosion, including wave speed, oscillations, creation, destruction, and synchronization.

With the information, engineers can, for the first time, develop tests to stabilize the often-chaotic RDEs and begin thinking about manufacturing methods for the engines.

The Tech Briefs Q&A reveals how Koch’s team developed an experimental rotating detonation engine. Learn about the University of Washington team controlled different parameters (like size of the gap between the cylinders) and recorded the combustion processes with a high-speed camera.

“We directly image our combustion chamber,” Koch told Tech Briefs in the Q&A. “We are watching — slowed down, of course — the actual detonation waves traveling around the combustion chamber.”

Each experiment took only 0.5 seconds to complete, but the researchers recorded these experiments at 240,000 frames per second so they could see the action in slow motion.

The goal of the mathematical model, according to Koch, was solely to reproduce the behavior of the pulses seem in the high-speed camera videos — to confirm that the model output matched the experimental results.

"I have identified the dominant physics and how they interplay. Now I can take what I've done here and make it quantitative," said Koch. "From there we can talk about how to make a better engine."
 

Questions in the Tech Briefs Q&A include:

  • What is different about a rotating detonation engine, compared to conventional engines?
  • What are the advantages of a rotating detonation engine?
  • How was the team able to examine different variables through your experimental engine?
  • What does the high-speed camera reveal?
  • What was Koch’s most interesting discovery through this process?
     

Read the Tech Briefs Q&A: Researcher Finds Promising Patterns in ‘Explosive Rotating Detonation Engine.

Read about Promising Patterns in ‘Explosive’ Rotating Detonation Engine