The jet propulsion with closed combustion type

[qumf]

The biggest difficulties to realize the new type jet engine are:

1. The force that some parts bear are not steady, It is harmful for these parts. My method is make parts bear force from pulling force to pressure or both. Thus that would be better. But it will be a little weigh after this measurement.

2. To regulate the work procedure for high efficiency, safety, and economy is really hard, but the jet have to work under many circumstances. The simple countermeasures are: 1. Set the engine rotation speed within a certain range while working. Out off the tolerance the engine will be inefficient, even dangerous. 2. Change the turbine’s position to some extent, move it forward and backward; change the flow resistance in general pipe; change the shape of the general pipe. 3. If necessary we can add openings or bypass on the general pipe.

 

Temporary I shall set the rotate speed of the chamber’s front door and back door at 5000~ 6500rpm, the blower’s rotate speed will be higher a lot. Set the gas pressure from blower increase by 30%. As to the chamber: length: diameter=1.5: 1 (All these datas depend on the size of engine)

 

I roughly calculate an example of the kind of jet. The size is petty big.

1. While without move, the pulling force per engine’s section area is less than current the most advanced engine by 15% because at this time there isn’t enough gas and rotate speed is limited. Once the jet begins to move, the situation will turn better.

2. to compare with the current jet, If they have same pulling force, the new type jet’s lighter by 30% (I estimate some components, maybe more actually)

3. to compare with the current jet, the efficiency of this jet is higher by over 80%

Regarding to common jet engine, the last two specifications are more important.

I have stated merit and dismerit. everybody,Is it worth practice?

[GAHD]

asssuming you are right in regards to feul efficiency and weight reduction it would be very worth it to develop the design. What you need is a prototype to make your claims more concrete.

 

I would like to know what makes you think it will be over 80% more efficient, that's quite the large number.

[qumf]

Dear GAHD:

 

I said "the efficiency is higher by 80%" because I only considered the two main parts' effect.compressor and turbine related to the current jet engine.blower and turbine related to my jet engine.I didn't considered the loss of energy at other portions(courses)' influence,such as convergence of gas.I think these influences are comparatively small or similar between two type of jet engines.

I ever calculated a common current jet engine before, the energy from spouted gas that can be utilized, about 70% of them will be absorbed by turbine for the compressor ahead.according to some specialized book I know the efficiency of compressor is 60% or less.The turbine in my engine can only absorbs 30% of the energy because the blower needn't increase the pressure so high. The blower's efficiency can get 85%.

Based on the premises, I said so. The proportion of efficiency 80% is acomparative data, not absolute data. Though some other course may influence the whole efficiency to big extent that I ignore improperly, I still think my engine' efficiency must be very high.

Who can guide me how to calculate the loss of energy at other course?

If the data I state here has some wrong or I misunderstand, pls point out.

[Ver]

Hi

Just a couple of thoughts re your engine qumf

Where will the drive for the doors be taken from.-- I presume there will be a reduction gearbox.

Will the doors to the combustion chamber remain flat as in the diagram.

Is the first compartment after the compressor an accumulator of sorts.

What size aircraft would you put it on.

What about noise because it is pure jet thrust and no bypass, considering modern bypass can put out perhaps 70 000lb thrust and more. A pure jet at those thrust levels with pulse system combustion may be a little noisy.

The basic system looks interesting. I hope you overcome any problems you encounter.

regards Dave R

[qumf]

Dear Dave R:

 

Thank you remind me these questions.

to drive the doors,I think I will use reduction gearbox. The consumed energy is small because we only need rotate the two doors . For now I would set the reduction rate (from turbine to doors )as 3~3.5 The gearbox is small.I did n't show the component in diagram.

In the example I calculated, the section area of the jet engine's out circle is 1.4 squre meter. i'm sure we can use small size. I think we can adopt it in ship firstly because We can cool it conviently and safety.We will use different parameters for different size of jet engine.

Truly spouting gas discontinously will cause noise.So big noise will happen in branch pipes. the gas from the commen piston type internal combustion engine( I don't know how to call by english) is also discontinuous.In fact over half of noise spread out from opening in this type of internal combustion engine. At the opening of the general pipe of my jet,the flow can be ensured steady and uniform . So the noise can be reduce. On the other side, all work course exist at any time. the noise might be absorbed each other.(to be confirmed by prctise), another method:I take some measurement on the branch pipes.absorb noise and insulate noise and make less noise happen.

I would like you say it feasible than interesting.

Thanks QMF

[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?

the noise might be absorbed each other

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.

[qumf]

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.

[qumf]

sorry,everybody

 

I find i made a mistake while I calculated the biggest possible efficiency of two type engine. I will consider it again.The deformation may influence the last result of the comparation of two engines.