Gluhareff 130R power failure issue still open ... Any Idear?

[luc]

Hi again ... Raymond,

I have one question for you ... If I take a vertical slice in the middle, is this still concidered to be a symmetry?

I know that if I take only one side of a tube, for example, I must specify that the other side is a symmetry of the side selected. But I have never worked using a slice in the middle, and especially with a circular shape.

I need your input on that one.

Regards,

Luc

[Raymond G]

Okey....Someone will have to help me learn how to make those nice rectangular when you quote someone previous paragraph or posting.

When writing your post, there are bottons for bold, italic, underline, quote, etc. Use the quote botton once to open, and again to close. This will make the nice box. One issue is tha it always seems to put it at the end of the entire post, so you need to assemble things correctly if you want to use the button.

Raymond ... was is "mdot"? ... As presume your are talking about mass flow rate ...

Correct. The symbol is a lower case "m" (for mass) with a "dot" over it to signify change with respect to time.

On our side, we never measure this data because Flow turbines and meters are very expenssive and just for measuring the thrust, we busted up 5 meters with the engine vibrations. It seem that electronics really don't shock wave. So we never spent the money for the turbines.

Also, we have a flow meter on the pumps, provided by the gas company but we found out that this thing was highly inacurate and that after 5 minutes of running, propane in the line was suck back in the reservoir. Remember, the reservoir become under vaccum after to much propane is sucked out (Winter condition, when almost no evaporation in the tank). Therefore, we could see reverse reading on the flow meter, screwing up at the same time, our reading.

There is another way, which I have used, and seen others try, that is straightforward and cheap. The only catch is you will need to use a propane cylinder instead of you facility supply. Get a canister such as shown in the manual. Put it on a balance style freight scale (your shipping dept should already have one). As you run the engine from this canister, record engine thrust and canister weight, every time the balance tips for a given increment, say 1lbm. You will get a very accurate ready of canister weight vs. time (i.e. mdot), and can correlate it with the thrust, which will probably also change with time (due to engine heating, tank pressure, tank cooling, etc.)
I used this method for my Senior Project when I was at engineering school. We designed, bult, and tested a cold gas thruster (cold rocket) using gaseous nitrogen as the working fluid. Everything worked very well; cheap and easy.

So... Now you know why I used the .78 figure. With restrictors, you CAN'T push more propane in, even if you wish for. You are limited by the size, the pressure, the media and the temperature ... That it. What ever the propane become in the coils or after the coils, the propane you push trough the orifices is the propane you get trough the nozzle, vapor or liquid.

The trick with a restrictor, is that its function is entirely dependant upon the rest of the fluid flow system. First, if you have enough restriction upstream, then the propane could already be gaseous by the time it hits the restrictor, and it will function as a flow limiting sonic valve. Second, if you have too much back pressure, i.e. downstream restriction, then the propane will not vaporize exiting the restrictor. Third, if liquid propane flows into the restrictor, and vaporizes at its exit, then it opperates a "restrictor" which is a calibrated pressure reducer. More mass can be pushed through it up to a point, and my quick hand calc suggests that the .078 in dia. spec should be adequate to provide the sonic fuel nozzle with the requisite .16 lbm/sec it is capeable of if the restrictor is seeing liquid propane.

Furtheremore, it should be easy for you brainiacs, to calculate what is the quantity of liquid propane going through one orifice of .078" (.00477 area). I can't, I am not that wizard... He he he.

Actually, not quite as easy as you would think. According to the manual and patent, the correct flow system involves a: tank, throttle valve, tubing run, flow dividing tee, parallel restrictor valves with phase change, parallel, heat exchanging coils with chemical reaction and heat transfer, flow combining tee, tubing run (with heat transfer), and nozzle. I've been too chicken to try it yet, especially since your facility plumping could be quite complex.

As for taking a slice for the computationnal domaine, I have no problem with that but remember, if I take a slice in the middle of the stack, the program won't consider the sides, and the stack is a circular shape, therefore, not constent from middle to side. My question ... Will it affect the results ???.

Consider your flow field as a cylinder. If you slice it in half lengthwise, you are left with a long planar surface (the symmetry plane), a long curved surface (the original flow boundary, i.e. the "metal") and two half circle ends. On the symmetry plane, you apply a symmetry bounday condition. If you cut this flow field in half lengthwise, then you will now have a flow field with two bounday planes, and two quarter circle ends. In this case you would apply the symmetry boundary condition to each of the symmetry planes. You could also slice this flow field in half lengthwise to creat e flow field with eighth circle ends, and two symmetry planes, and so on, and so on....

1) So ... Do I change the boundary condition and add Flow figure? or Do I live it as it is, wich is 225 psig. @ 1200 °F.

2) If I had a flow, what will it be?

Personally, I would MEASURE mdot before I spent anymore time running CFD analysis. This will tell you far more about how the system is behaving, and then we will know what we should enter for the boundary conditions. It would be very helpful to also measure temp and press in the fuel nozzle (upstream of the nozzle throat) at the same time that you measure mdot. That way you will KNOW exactly what you are delivering to the flow nozzle.

3) Do I take a slice or not?

I would. After measuring mdot, that is.

Regards,
Raymond

[luc]

Hi again Raymond

The trick with a restrictor, is that its function is entirely dependant upon the rest of the fluid flow system. First, if you have enough restriction upstream, then the propane could already be gaseous by the time it hits the restrictor, and it will function as a flow limiting sonic valve. Second, if you have too much back pressure, i.e. downstream restriction, then the propane will not vaporize exiting the restrictor. Third, if liquid propane flows into the restrictor, and vaporizes at its exit, then it opperates a "restrictor" which is a calibrated pressure reducer. More mass can be pushed through it up to a point, and my quick hand calc suggests that the .078 in dia. spec should be adequate to provide the sonic fuel nozzle with the requisite .16 lbm/sec it is capeable of if the restrictor is seeing liquid propane.

Okey ... I remeber 2 years ago, we ran this engine using a lift truck propane cylinder and the engine emptied it in 5 minutes. Actually, we did 3 run and the time was 5.00, 5.04 and 5.07 minutes. A lift truck cylinder contain 33 liters of liquid propane. So, using the time above I have caculated the consumption to be .11 liter/sec. But tomorow, I have requested a run using a similar cylinder over a squale, this way, I will have real numbers and the orifices will be .078" dia. each.

Consider your flow field as a cylinder. If you slice it in half lengthwise, you are left with a long planar surface (the symmetry plane), a long curved surface (the original flow boundary, i.e. the "metal") and two half circle ends. On the symmetry plane, you apply a symmetry bounday condition. If you cut this flow field in half lengthwise, then you will now have a flow field with two bounday planes, and two quarter circle ends. In this case you would apply the symmetry boundary condition to each of the symmetry planes. You could also slice this flow field in half lengthwise to creat e flow field with eighth circle ends, and two symmetry planes, and so on, and so on....

In this post, I have included 4 pictures. The first 2 shows a sliced computational domaine (Perspective and front view) and the last 2 pictures shows a 1/4 tube computational domaine ((Perspective and front view). Tell what scenario would be the best, sliced or 1/4 tube. Also, note that I have removed the 90° inlet tube going in the nozzle. This tube only complicated the computational domaine setup and from past experience, the only way this thing is 90° turn instead of a radius, is to avoid nozzle disalignment cause by thermal expansion of the tube. I don't beleive it will change the results if I remove it.

Tel me what you think ... Raymond

Regards,

Luc

[luc]

Damnnnn .... Look at my previous post ....

He he he ... Am I not good. Nowwww ... I am a posting pro.

Cya,

Luc ....Out

[Viv]

Ok Mr pro poster:-) the download works ok, I am still here just been a bit busy and the maths is way over my head at the moment as well:-)

The next thing to do is to get the inlet tuned up I think once the nozzle is done and dusted.

Viv

[Raymond G]

Okey ... I remeber 2 years ago, we ran this engine using a lift truck propane cylinder and the engine emptied it in 5 minutes. Actually, we did 3 run and the time was 5.00, 5.04 and 5.07 minutes. A lift truck cylinder contain 33 liters of liquid propane. So, using the time above I have caculated the consumption to be .11 liter/sec. But tomorow, I have requested a run using a similar cylinder over a squale, this way, I will have real numbers and the orifices will be .078" dia. each.

Perfect. This is exactly what we need. Will you be able to gather the thrust, press at nozzle and temp at nozzle data simultaneously? That would be perfect.

In this post, I have included 4 pictures. The first 2 shows a sliced computational domaine (Perspective and front view) and the last 2 pictures shows a 1/4 tube computational domaine ((Perspective and front view). Tell what scenario would be the best, sliced or 1/4 tube. Also, note that I have removed the 90° inlet tube going in the nozzle. This tube only complicated the computational domaine setup and from past experience, the only way this thing is 90° turn instead of a radius, is to avoid nozzle disalignment cause by thermal expansion of the tube. I don't beleive it will change the results if I remove it.

Looks great! I would use the 1/4 slice (pg. 2). You can apply symmetry BC's to each of the two long flat faces. You are right that the right angle probably complicated the CFD analysis (i.e. slowed it down).

I am really looking forward to seeing your results. I think they will tell us a lot about what is going on with this thing.

Regards,
Raymond
[/quote]

[luc]

Hi Raymond and guys,

Perfect. This is exactly what we need. Will you be able to gather the thrust, press at nozzle and temp at nozzle data simultaneously? That would be perfect

Yes my friend ... As of right now, my technician is seting up the engine to run with a weighted cylinder and all instrumentation will be hooked up to the engine (i.e: LoadCell, Nozzle temp. probe and nozzle pressure).

One question on that running, should I do it inside (@ 70 °F) or outside (-6 °C today)? Give me a quick answer. We will be ready to run in about 1 hour.

Looks great! I would use the 1/4 slice (pg. 2). You can apply symmetry BC's to each of the two long flat faces. You are right that the right angle probably complicated the CFD analysis (i.e. slowed it down).

Okey .... Now that we have a plan and when I will get back with the run results, we will need to establish what boundary conditions we put in the CFD sim (i.e: Temp., pressure or Flow or all of them).

I am really looking forward to seeing your results. I think they will tell us a lot about what is going on with this thing

Yeap ... me to Raymond. You will get the results very soon today, so stby and don't go to far. As for the CFD sim, it will probaly take more time but at least, we will start it today.

FINALLYYYYYY .... We will lift the curtain of the damn engine and for many generation to have a powerfull beast to push their damn gokart. Do you imagine guys, every time someone will go hit a wall at 150 mph, with 130R Rev. 2 engine, they will think about us ... He he he.

I am not sure I want that .... he he he.

Cya in an hour or 2.

Luc .............. Out

[Raymond G]

One question on that running, should I do it inside (@ 70 °F) or outside (-6 °C today)? Give me a quick answer. We will be ready to run in about 1 hour.

Inside at 70 F definitely. If Gluey did it in Souther California, then you would do best to try and duplicate that environment, in case your different environmne tis where the discrepencies lie. Good Luck

Raymond

[luc]

Okey guys,

Here are the results of the running:

Liquid propane cylinder : Full @ 58 pounds 4 onces, Empty @ 30 pounds.
Fuel consumption was : 28 pounds 4 onces of liquid propane.
Running time was : 4 minutes 43 seconds
Ambient Temperature was : 63 °F
Thrust recorded was : 46 pounds
Coils inlet propane Temperature was : 39 °F
Nozzle temperature was : 1060 °F
Nozzle pressure was : 150 pisg.

Okey ... here is how I have converted the fuel consumption :
28.4 pounds = 12.882 Kilo = 12882.02 grams
.5005 g/ml is the density of liquid propane @ ambient temperature (20 °C)
So, 12882.02 grams / .5005 g/ml = 25738.30 ml = 25.738 liter.
So, 25.738 liters / 4:43 minutes (Wich is 283 sec.) = .090 Liters/sec.
Or, As Gluey would calculate it, it would be : 7.821 lbs/lb/hr.

Damn ... Look at this, I come to 7.821 lbs/lb/hr and Gluey said .78 lbs/lb/hr. Did he put the "." at the wrong place ?

I have also attached to this message, a recording of the engine. Sorry for sound quality, I only had a laptop with a cheap microphone and did the recording using Windows XP recorder.

So, You have enough to play now. I will be waiting for your comment and recomendations before starting the CFD simulation.

Cya,

Luc

[luc]

Damn ....

Forgot the sound file.

Sorry guys ... here it is.

Cya,

Luc

[Raymond G]

Liquid propane cylinder : Full @ 58 pounds 4 onces, Empty @ 30 pounds.
Fuel consumption was : 28 pounds 4 onces of liquid propane.
Running time was : 4 minutes 43 seconds
Ambient Temperature was : 63 °F
Thrust recorded was : 46 pounds
Coils inlet propane Temperature was : 39 °F
Nozzle temperature was : 1060 °F
Nozzle pressure was : 150 pisg.

mdot (calculated)=.06 lbm/sec
mdot (measured)=.10 lbm/sec (should not be more than calc. !!!)

That is very strange. Possibilities are:

Leak in system somewhere
liquid propane at the fuel nozzle (not likely with a nozzle temp of 1060F)
Nozzle throat larger than .250in (12,7 mm dia) throat diameter spec'd.
Instrumentation error
Something we're missing ;-)

Okey ... here is how I have converted the fuel consumption :
28.4 pounds = 12.882 Kilo = 12882.02 grams
.5005 g/ml is the density of liquid propane @ ambient temperature (20 °C)
So, 12882.02 grams / .5005 g/ml = 25738.30 ml = 25.738 liter.
So, 25.738 liters / 4:43 minutes (Wich is 283 sec.) = .090 Liters/sec.
Or, As Gluey would calculate it, it would be : 7.821 lbs/lb/hr.

That is a scary possibility, but seems a little unlikely, given other data presented in the manual.
All of this data seems consistent with the engine running too rich, i.e., low thrust, high fuel flow. What is the combustion chamber temp? What color is the cobustion chamber when running? Is there noticeable smoke in the exhaust plume (maybe not a possibility with propane)?

Raymond

[luc]

Okey,

I think the error come from to points.

First, the engine as to warm-up for some time and need propane to do that. So it took aprx. 15 to 20 sec. at 80 psig. to warm up.

Second, yes we found out a small leak at the safety fuel shut-off valve.

Okey ... We are not gonna cut hairs in 4 because of a few lost drops and a few seconds of warming-up. The scale used is a shipping needle scale (No budget for $500 digital scale) and it is outlawed to tempered with liquide propane cylinder and I already have one tempered. Can't have a second one to rapidly switch cylinder after warm-up.
So, we weighted the cylinder @ full, ran and weighted again when empty. Can't do more then this.

We took 28.4 pounds of liquid propane in 4.43 minutes.

What is the average CFC?
Are my number and calculations good?
Why can this damn beast give more thrust?
Can we start the CFD simulation?

Regards,

Luc

[luc]

Hooo....Sorry I forgot,

What is the combustion chamber temp? What color is the cobustion chamber when running? Is there noticeable smoke in the exhaust plume (maybe not a possibility with propane)?

We can't measure the chamber temperature. We puschased temp. probe rated @ 2000 °F and obviously, it is not enough because we read "OL" (Over Load) for the one in the chamber and at the tail pipe. One thing I can you do ... It is above 2000 °F, that for sure ... he he he.

The chamber is light cherry red and it is so hot, we can see the coils inside. And no ... Their is no smoke coming out of the engine.

Cya,

Luc

[patrick35]

RAYMOND , you ask for color of the combustion chamber ?!?! . there is , as you can see it's very hot lollll .

PS : you can see behind the guy on the door of the closet it's write --> ""ACIDE please put back in place after use "" outchhhhh ....

so there is the pics if i can upload it , if they are not there i,m gonna contact some one to help me..

PATRICK

[Viv]

What can I say! awsum pictures guys:-)

I note the even heat in the nose cone.

But the audio recording I am afraid to say is the worst I have ever seen:-) Graham has probably seen worse though as he is the expert.

It is so badly clipped I cant do a thing with it I am afraid, mayeb we should just fly Graham over for a test run and let him do the recording:-)

Viv