liquid rocket gas generator question

[racket]

Hi ( do you have a name?? , its friendlier if we call each other by name )

The GT6041 wheel with a 1.47 A/R housing (like I used on my GT6041 afterburning kart ) jetandturbineowners.proboards.com/index.cgi?board=diygeneral&action=display&thread=78 .....................has a CORRECTED mass flow of ~90lbs/min , in reality when used as a gas turbine engine the flow is what the compressor delivers , namely ~165 lbs/min - 2.75 lbs/sec UNCORRECTED.

With the comp running at maximum tip speed theres a ~4.2:1 pressure ratio at 65% effic , this results in a ~225 deg C rise in temp during compression and equates to a horsepower output of ~137 hp/lb of mass flow , or ~378 hp for our 165 lbs/min .

The thing with turbines is we can't fudge the numbers as its all "simple maths" , the GT6041 flows ~2.75lbs/sec and would have a gas velocity of ~2,000 ft/sec at the scroll throat .

Lets workout the kinetic energy ...........0.5 X 2.75 X 2000 X 2000 div by 32.2 = 170807 ft lbs/sec , divide by 550 ft lbs/sec/hp = 310 hp , now this wouldn't be enough to drive our 378 hp compressor , so theres further pressure drop within the turb wheel which produces the remaining 68 hp to balance the comp requirement .

As I said , its just simple maths that can't be fudged .

So , I'll re-ask the questions .......................what horsepower are you designing for , and what sort of mass flow was the Turbonique using for its engine ??

Some extra details on the Turbonique would be appreciated so that I can get a better appreciation of what you'll require :-)

Cheers
John

[spiveycool]

My name is John. The Turbonique details are on line at www.freepistonjetengine.741.com/myfiles/turbonique/index.html

[racket]

Hi John

Thank you for a really good Link , its answered all the queries I've had about these units over the years :-)

Ok , from what I can see in the graph on page 86 the Model S-12 requires a "fuel" flow of ~5 to 6 gallons per minute , ~50 lbs/min or 0.83 pounds/second for its ~350 hp output , a similar or greater mass flow of oxygen/fuel/water would need to be supplied for a similar power output.....................those Turboniques were thirsty buggers :-(

The thrust engine stats ( p 83) were interesting , using the Model T-12 fuel flow was ~6.75 gpm for its thrust of ~175 pounds , thats ~0.95 lbs/sec flow at ~5,800 ft/sec efflux velocity, actually the graph figures don't completely make sense when the maths is done , but they're "ballpark" .

Cheers
John

[spiveycool]

The Turbonique setup was designed in the early sixty's. I know that materials/machine tool/engineering have made tremendous advances since then. It amazes me that they managed to do what they did. I think it is past due for this to be dusted off and brought up to date. I want to update the turbo/turbine setups. I have little interest in the thrust engines as there are better solutions to that problem. As I see it there are many uses for very high output/short duration turbo machinery and I personally have a few projects that require this setup. If nothing else I can always build some copy's of the old stuff but i know that I can do better than that with what is now available.