Rotary vs Turbine (Jet)
 

I know a jet has a continuos burn and is not practical for small time apps. Is the rotar Mr. Felix's way of introducing the efficiency (at least hp/cc) to the automotive world?


A jet still uses the Otto cycle, maybe all fuel burners do, so maybe it was taken into consideration when he found a way for the turbine aka eccentric shaft to be propelled/spun using rotor housings.

Any thoughts......please share

wat

Well now....

For one, the Otto cycle works on these paths (ideally). Isentropic compression (intake), constant volume heat addition (fuel is burned), isentropic expansion (power stroke), constant volume heat rejection (exhaust). A turbine engine DOES NOT operate on this principle.

The turbine engine is based on the Brayton cycle and is as follows. Isentropic compression (by compressor blades), constant-pressure heat addition (combustors), isentropic expansion (in the turbine), constant-pressure heat rejection (exhaust nozzel).

A constant pressure process is not even close to a constant volume process. The ICE burns the fuel at around the top of the piston throw and it will ideally burn before the piston moves far down. Therefore, the combustion applies pressure while the cylinder's volume is relatively constant. This pressure exerts a force on the piston's surface area which in turn propels it downward.

The turbine uses a nozzle along with fan blades to compress the air where it then enters the combustor. The fuel air is ignited and allowed to expand immediately towards the rear of the engine. This expansion is is under a constant pressure. The air then moves through a series of blades within a diffuser and exits the engine. As you can see above, the turbine engine and rotary engine have very little in common (except that they produce, usually, positive net work). Hope this was informative....

^ I swear you're taking the same class I am...

Which class? I've taken 5 thermal-fluid science classes so far. When I graduate in May I'm heading to work for GE Aviation on turbine engines. I absolutely love this stuff.

I'm taking a thermo fluids course. I'm at Mac right now. Where do you go?

When I was at Sheridan College, I worked at Pratt and Whitney Canada in the Drafting and Combustion Departments. It was by far the most interesting job I've ever had in my entire life. The few minutes per week I was able to walk through the Production area made sitting at a desk the rest of the time worth it. I'm sure GE would be no different! Good luck!

I was kind of right.

http://www.mazda.com/mazdaspirit/rotary/story/

It just seemed like Wankel liked the jet engine but saw from it's constant pressure process that it was impractical for stop and go, so he made a compromise.

In the link it is coined as, half turbine/half reciprocating

jet engines work better for jets and rotary works better for everything else

I'm currently at Bucknell University.

Im a jet engine mechanic, all I know is they suck, compress, bang and blow:) and make a lovely sound;) Hmm sounds like a turbo rotary:)

i lol'd :)
The only reason turbines are used in aviation is because they make mega-huge power for their size, weight, and cost. piston and rotaries can't come anywhere close to a turbine's power to weight to operating-cost ratio.

anyways, rotaries are simpler (in construction, if not design) than piston engines. Lighter and MUCH fewer moving parts to create friction and break. theoretically, this would mean that rotaries should get better mileage and last longer than comparable piston engines, but pistons have had a head start in design and improvement and rotaries are still catching up. given time and research, rotaries could replace gas powered pistons. (has anyone tried to develop a diesel rotary?)

Only thing rotaries really have in common with turbines is that they go 'round :)

Well if you're interested, SAE paper 2007-01-1254 is about the use of Direct Injection- Homogeneous Combustion Radical Ignition. This is relatively similar to diesel compression ignition. This engine used hydrogen but the team also published a paper using methanol and I believe are working on other fuel sources as well. DI-HCRI allows for spontaneous and even combustion without the use of an igniting heat source. It also does not use a throttle to control the engine speed, much like a diesel engine.

It is very similar to the homogeneous charge compression ignition but is easier to control and produces a cleaner exhaust. (This engine runs at a lean condition so few hydrocarbons are expelled). It's a rather interesting idea which could potentially lead to some interesting advancements in rotary technology.

hell yea i work on T64-GE-419 in the navy and it is beast especially in the winter they keep you warm when the helo turns up :)

http://www.turbinecar.com/turbine.htm
http://www.turbinecowboy.com/carstru...hotoalbum_view
http://science.howstuffworks.com/m1-tank2.htm

No, hp/cc is just a benchmark for engineering geeks and enthusiasts, and has no practical value. However, he may have been looking for better mechanical efficiency when he designed his engines.

The turbocharger evolved into the turbine engine and the supercharger evolved into the rotary engine. Hopefully that explanation will answer your question better than the engineering geeks and their fancy college words. ;)

As stated in other posts, a typical turbine engine operates by the Brayton cycle.

That's ironic, I would have thought that the turbocharger evolved from the jet engine.

i thought we were talkin about my ex girlfriend for a minute here til i read the rest of the thread.

anyone here ever try making one of those jet engines with a car turbo?

Homemade Jet Engine Video

nope. aircraft were turbocharged long before they were turbined :)

Actually, it was only a few years. The two technologies were very close to each other (with respect to aviation).