[kach22i]

Here is a sceptic on it:
Wave Disk Engine – New engine design from MSU and ARPA-E that sounds too good to be true – The Blogs at HowStuffWorks

Why does this sound too good to be true? Because there are limits to how efficient a real-world gas turbine engine can be, and the claims here (“the generator will use 60 percent of fuel for propulsion”) are beyond those limits. In addition, when looking at the image on this page…

* The first thing that is uncomfortable is the fact that intake and exhaust happen simultaneously, and generally that opens the possibility for flow-through.
* Second, there is no obvious compression step, and compression is important to efficiency. The image says, “Shock waves compress air and fuel”. The only way for this to happen, since there is neither a mechanical volumetric change evident (as in the compression stroke of a piston engine) nor a ramming compression step (as in a ram jet or pulse jet engine), is for the “shock waves” to create some sort of stratified charge in the closed-off chamber. This would have to be a completely new technique, and there is no description or detail on this technique offered, so we are left to wonder what the technique is doing. Also note that if compression is happening through stratification, there would need to be a vacuum forming elsewhere in the chamber. (While it is possible for pulse jet engines to operate statically (without ram air), their efficiency is generally terrible because of lack of compression. So the wave disk engine, again, would be breaking new ground).
* Keep in mind all of the problems that Rotary Engines have with sealing. A gas turbine engine (or a ram jet engine) does not need seals because the compression phase acts as a wall that forces all thrust out the open end. There appear to be no seals in the wave disk engine, so what keeps the compressed stratified charge in its chamber?

I would love to be proven wrong on this – the world could really benefit from a 60% efficient engine. However, these three problems lead me to believe that this engine will not be 60% efficient in the real world. We can revisit in a year and see if I am right or wrong.

Lots of cool stuff on the Dr's website:
http://www.egr.msu.edu/mueller/