the jet propulsion with closed combustion type

[qumf]

Originally Posted by Ver

Hi
I understand you may use it in a ship first. Ok- cooling and noise no problem.
I would be interested in your drive system in a ship. Perhaps a free turbine or adding an extra turbine and driving off the compressor shaft. How will you do that?
Do you mean noise cancelling perhaps.
I can see this working but you are brave to take it on and you have seen some of the stress problems that may arise. I hope it all goes well
regards Dave R.

Hi

I correct two sentences:
"In fact over half of noise spread out from opening in this type of internal combustion engine" should be corrected as" over half of noise create at the opening from the final pipe to outside".
"the noise might be absorbed each other" should be corrected as "the noise will be absorbed by other other to some extent". Actually I don't believe the whole noise can be absorbed by them even though the principal affects at the situation.

I don't understand what you said about using the jet engine on ship. It only need a blower while normal working. let it drive itself! including the blower.

Though I have some ideas how to practise the new type engine. But I also lack some knowledge that has been adopted in current internal combustion engines. I know we can get it but I don't clear how to practise by detail. It also must cost a lot of money.

[Ver]

Hi
Qumf. Sorry I may have misunderstood you as using it in a marine application first.

I think we can adopt it in ship firstly because We can cool it conviently and safety

Jet engines are used often in modern warships and they need a transmission system for the prop.
regards Dave R

[Boerseun]

Interesting design, and approach to the whole issue.

I see a couple of problems, though...

First off, unlike a conventional jet engine, your design would be incredibly sensitive to RPM, and the current air conditions (humidity, particules, etc.) which would determine the burn rate.

If you go over a certain RPM, and the intake doors rotate too fast, the door will open again for intake before the mix has completely combusted. Humidity will play a role in the time it takes to achieve full and complete combustion. Altitude will also play a major role. In other words, you might have an engine with a very slim operational margin. It cannot run at less than 5,000 RPM, but then again, it can't run at more than 5,500 RPM, for example.

Okay - with incomplete combustion (i.e. the doors opening too fast) you'll have a normal gas flow like a normal jet engine - just much less effective than a normal jet, because the design drastically changes the airflow a couple o' thousand times a minute. So the engine'll still run, but much less efficient. To obtain your objectives, you're gonna have a very slim margin to play with, probably limiting this design to marine use, where gearboxes running off the engine can allow variable prop speeds for a constant RPM - which you can't do in flight.

[qumf]

Boerseun:

Thank you remind me the things. Though I can't understand all what you said, I try to answer you.

The RPM I proposed is for two purposes: 1. to compete with current jet engine. 2. to regulate jet engine conveniently. AND it is under normal condition. If the conditions change as you stated, I will change ERP, thus the efficiency and power/second will change. The current jet also reduce the efficiency under this condition. Later I will think if the method to regulat work course that I have said can solve and regulate efficiently under the hard condition you said, whether they can regulate themselves effectively .In a word I will ensure complete combustion.
If the size ogf jet engine change, I think the RPM will change.

I will install some sensor to get some information to adjust sth to fit condition's change.(that is usually been used)

The only thing i am a little afraid is the particulates you mentioned.

In a certain range,Altitude(air pressure) has little influence to combustion speed.

If I use it in ship,I needn't prop,pls advise.

regards

[Ver]

Hi

If I use it in ship,I needn't prop,pls advise.

If you use this system in a ship you will have to convert straight jet thrust to mechanical torque to drive the ships propeller. I dont think you would intend to use straight thrust. Your basic engine will need to be specificaly designed for torque output and not as in an aircraft which would be straight thrust from the jet pipe.
To provide this turning power to turn a gearbox input drive you will need to connect mechanicaly to the engine.
If you wish to use the rotating part of your engine to connect a drive, you will need to convert some of the thrust by adding one or more turbines to that shaft and drive directly off that shaft. The other way would be to fit a free turbine which is one or more stages of turbine that will rotate independently of your basic engine. Your gearbox would fit to this part. The drive to your gearbox would probably be a quill shaft drive from a bevel gear running down the free turbine support. Free turbines are used in this way for helicopter engines
regards Dave R

[qumf]

Dear Dave R:

Originally I thought that I only used the straight jet thrust to push the ship.

If I have to use the propellor ,I will consider you suggestion of adding a free turbine and transmission.
Thanks

[qumf]

Dear Boerseun:

AS you said "the current air conditions (humidity..)" , Trully that would influence the combustion speed.If the situation is slight, not severe. the jet engine can adjust itself to fit the situation. If combustion is in complete, the gas's pressure after combustion will be lower than normal ,then the rotate of turbine will smaller than normal;the doors of chamber rotate slower than normal. thus the time provided for combustion will be longer. the combustion will became complete.

If the situation became severe, I would rather to chage the parameter of jet engine that is different from jet for aeroplane. Such as the Diesel engines for ship and truck, they have very different parameters .
If I don't change a little on the jet under severe situation, Even if I can adjust it for efficiency and safety, the power will drop a lot. That is improper.

[qumf]

Dear all:

I've thought out a way to calculate the energy directly used on thrust/ fuel. I'll tell you the the absolute efficiency of both the current jet engine and the new type jet engine.
One of my jet's weakness is heat load. At some positions in my jet it is harder than the current jet engine. maybe I need a additional facility to provide energy to blower instead of turbine.After all the blower needn't a lot of energy.

[qumf]

Deleted!
I deleted the reply, because the method of analyse is too rough, may cause the reader misunderstand. Later 5 or 6 replies behind just for reference.
there is correct analyses in later replies( from reply#59).

I remain the illustration, it might be useful later. by now do ignore it.

qumf 2/11/07

[qumf]

I didn't express clear about estimating the biggest possible efficiency in last post. To estimate the efficiency of the current jet, we need to know the temperatures of several courses of gas in jet( not only two temperatures). I searched the date and calculated the efficiency again, the difference is very small.
As to the new type jet, though I haven't practice, I can calculate, or refer to the current jet/internal combusition engine if they have similar course ,or refer other mannul to get the temperatures and pressure of the courses.