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The jet propulsion with closed combustion type


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looks like the inside of a pulsating shower head. alot like a rodial engine.   purty neat engines here http://www.keveney.com

Dear DFINITLYDISTRUBD:   I suggest firstly you fixed the engine with a shelf. after adjust it ,it can work normally, You let it drive your cart.

dear all:   I always think whether the new jet can work under various conditions. to adopt some cases if it must be adjusted.   In some cases we hope the jet provides less push force than common. I a

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DFINITLYDISTRUBD:

 

for now I think 80psi is too high if you use my disign.. We needn't the so high pressure because the jet can get pressure further higher by the combustion. If you use your design,maybe the combustion can't provide the very high pressure because you don't utilize all volume as air.Thus you need to adopt a higher pressure.

 

In my design, I think the pressure from compressor is 30-35psi is proper. I prefer you can get more cfm.

 

i also think the rotation speed is too high(120,000 rpm). if you drive the rotary valve by the turbine, you should reduce the rotary speed a lot to the valve by other transmission case.

 

I'll calculate and give some idea if there is sth need to be updated.

 

Any question, pls ask me.

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DFINITLYDISTRUBD:

 

What size of the compressor is? Is it 6” that you said before?

I calculate roughly, the inlet hole of the compressor is about 2”. Is it close to real diameter?

I am not familiar with centrifugal compressor.

 

You can try to drive the valve with very high speed; your design is different from mine after all. But you should prepare to reduce the speed if it is not effective. The transmission is small size because it need not to transfer big energy.

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DFINITLYDISTRUBD

 

I know why you prefer higher pressure than more currency. You can’t be clear what pressure that the combustion in your jet can get.

Is there enough energy to drive the turbine?

I remind: but only the energy from combustion to turbine should be taken into account, you also consider the additional energy to create pull force. It is a propulsion that you want to make.

It is hard for me to estimate the pressure from combustion in your design though the mechanical structure is simpler than mine. The combustion in your jet is neither completely nor kept closed in volume comparatively. It is hard to estimate the increase on pressure.

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DFINITLYDISTRUBD:

 

I think the rotary valve’s speed should be less than the turbine’s speed a lot. Maybe you use belt transmission to reduce the speed from turbine to valve. After all we are doing experiment.

 

I hear that there are many funds in USA, can you apply some money from them for your research?

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When I analyzed the efficiency of my jet in post#59(page 6), As to the new jet: efficiency=1-k*[u^(1/k)-1]/(u-1)/{w^[(k-1)/k]}

I ever said that the increase of gas pressure “ U” can get 9 -10 theoretically. I explain the reason below:

by many document, the mixture of air and methane burns from the standard condition under constant pressure, the highest temperature can get 2200K -2300K if it has best concentration. What is the temperature while burning with a constant volume?

I think the quantity of heat from combustion are same by either way, constant pressure combustion or constant volume.

q= Cv*ΔT1=Cp*ΔT2 ,Cp/Cv=k

If we know the increase of temperature by constant pressure combustion, also can know the increase of temp. by constant volume combustion.

K=1.4, (actually k may changes a little while very high temperature). I calculated, the highest temperature can get 3000K.

If other fuel be used instead of methane, the quantity of heat will be less a little, not much. Here I don’t list more data. I think it is because they are all composed by similar elements.

After we have the idea of the range of increase of temperature,

per the formula: Pv=RT if v is a constant, P varies with T. If T increases by 9 times, P increases by 9 times.

Can I adopt the formula: Pv=RT? In the course the pressure is high, the temperature isn’t low. I think we can use the formula. Or the deviation is small, it doesn’t influence the use.

The analyses upper is theoretically, but I think it is basically conform to reality. All the data I later listed in the example in the post is in this range.

 

The example I listed is methane burning at the standard condition, that is under about 1 bar. In my jet the burning is rarely under 1 bar, maybe much higher. I checked some material, Cp and Cv is directly relative to the composition of the gas and temperature. While the pressure isn’t very high, Cp and Cv vary little. So I think, If only pressure vary, others keep same, the final temperature after combustion almost same(vary little).

 

Pls point out the mistake if it has.

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Re: the jet propulsion with closed combustion type - 06-16-2006, 11:24 PM

 

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DFINITLYDISTRUBD:

 

I think the rotary valve’s speed should be less than the turbine’s speed a lot. Maybe you use belt transmission to reduce the speed from turbine to valve. After all we are doing experiment.

 

I hear that there are many funds in USA, can you apply some money from them for your research?

First off.......why the desire to complicate? also more parts = more friction, more things to go wrong, less efficiency!

 

As to funds they may be out there but they are verrrrrrrry difficult (if not impossible) to get!

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First off.......why the desire to complicate? also more parts = more friction, more things to go wrong, less efficiency!

What you said is reasonable at some extent, but sometimes you have to give in because it may relative to principle, sometimes the other side has bigger reason. After all you are doing experiment, you can try many thing, I hope the machine is simple.

 

As to funds they may be out there but they are verrrrrrrry difficult (if not impossible) to get!

What you research is a big project, it has big meaning,relative to save a lot of energy, why can't you try?

 

at last,how well do you fabricate you engine now?

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DFINITLYDISTRUBD:

 

how well do you assemble you engine?

 

Attention, safety is first.

I worry you are too hurry,that cause some thing out of imagination.

Each time you start the engine later, In advance you should conside how to deal with sth suddenly occurs.

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how well do you assemble you engine?

 

Attention, safety is first.

I worry you are too hurry,that cause some thing out of imagination.

Each time you start the engine later, In advance you should conside how to deal with sth suddenly occurs.

 

Verrrrrrrry sorry about not getting back to you sooner!:)

 

Yes saftey is a big concern with all of my projects (I'm quite accident prone!).

 

Progress is very slow and problems with the valve timing aren't helping matters either nor are my long hours at my day job. (There should be a law against the hours I must work just to keep my job...all overtime is manditory at the shop!) But I have fired it up on several occasions. So far it runs but not well...I've got a few tricks left up my sleeve to try.

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DFINITLYDISTRUBD:

 

It seems that the gas in your engine only be ignited occasionally, it is unpleasant.

Though we want to adjust for work orderly, it is hard to find direction. maybe you will try on many portion. I also feel hard to analyse the course.

You might adopt my design finally.

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DFINITLYDISTRUBD:

 

How well do you solve the problem?

Could you tell me the size of the chamber in your machine, It seems that you only use one chamber. (You have told me before). If you can tell me the actual rotation speed, that would be better, can you test it? I try to analyze it and solve the trouble.

Can you give a photo of your machine?

If you feel inconvenient, you can write to my personal E-mail: [email protected]

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DFINITLYDISTRUBD:

 

Your engine can’t work continuously,I just consider the portion of combustion, if I ignore the cooperation between the portions inside.

 

I try to analyze: you just use a chamber, and the shape inside chamber is simple. The combustion and the flow of the gas exist at the same time. You didn’t control the flow speed and position of flow well either. I think it is hard to keep the flame steady. The fire is blown down.

On another side, the composition of gas near the flame is also important. If it is improper, the fire disappears.

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