Starting next build, need suggestions on instrumentation

[hosedup]

Most likely going to use a Holset 3522950
.

Inducer diameter: 55mm (opening is 95mm and funnels down to 55mm)

Exducer diameter: 75mm

From what I gather, P1 is inducer pressure (basically atmosphere), P2 is compressor output, P3 is combustor output, and P4 is turbine output.

When it comes to what points that should be monitored, oil pressure, P2, P3, and TIT at minimum and add P4 and TOT if nozzle and/or after burner is employed.

For data ranges, I am thinking 0-100 PSI gauge for oil, 0-15 PSI (or 0-30?)  for P2, 0-30 for P3 and P4.  For temp, standard type K thermocouples for TIT and TOT.  

Im considering a flow meter for the propane. (I may have an air flow meter laying around that might have the right range, just need to convert to propane density)  What is involved in estimating propane flow rates in CFM?  

When it comes to RPM, i'm not sure if its critical and if it is, what instrument to use.

Other than that, what other instrumentation is absolutely required and what is nice to have?

[racket]

Hi

Gauges for P2, oil pressure and TOT are obligatory , P2 0-50 psi , oil 0-100 psi , TOT 0->1,000C , DON'T measure TIT , if the thermo detaches it goes through the turb wheel .

A P4t pitot in the jetpipe is very useful for determining how well the engine is performing , same with a T2 reading .

Probably better to work in weights for fuel flows .

RPM can be read with a hand held non contact tach , cheap on Ebay

Cheers
John

[hosedup]

Nov 24, 2019 16:11:03 GMT -5 racket said:

Hi



A P4t pitot in the jetpipe is very useful for determining how well the engine is performing , same with a T2 reading .

Probably better to work in weights for fuel flows

Cheers
John

I can work with weight / time. Can you give we an estimate as to what kind of range I'm going to need?

Are you suggesting using a pitot tube to measure nozzle in out delta P or just measuring P4 at the turbine? If the latter, wouldn't a regular pressure gauge work?

[racket]

As for propane weights , roughly 1/60th of airflow , so lbs/min of propane = lbs/sec of air ............trying to measure CFM would be impossible due to the varying supply pressure/density of the propane at different P2s.

The pitot in the jetpipe measures total pressure , there can be several psi of dynamic ( velocity) pressure that needs to be added onto the static pressure to get the full amount of "energy" leaving the turbine wheel , once we know the full jetpipe energy we can then determine the pressure ratio across the turb stage and from that , in conjunction with P2 and T2, get some idea how well the engine is working .

Another benefit of the P4t is mass flow and potential thrust can be calculated taking into account jet nozzle sizing and jetpipe temperatures ...............all things are interconnected with a turbine engine as theres no "valves" in the system to isolate one part from another .

Cheers
John

[hosedup]

Nov 25, 2019 15:50:23 GMT -5 racket said:

As for propane weights , roughly 1/60th of airflow , so lbs/min of propane = lbs/sec of air ............trying to measure CFM would be impossible due to the varying supply pressure/density of the propane at different P2s.

The pitot in the jetpipe measures total pressure , there can be several psi of dynamic ( velocity) pressure that needs to be added onto the static pressure to get the full amount of "energy" leaving the turbine wheel , once we know the full jetpipe energy we can then determine the pressure ratio across the turb stage and from that , in conjunction with P2 and T2, get some idea how well the engine is working .

Another benefit of the P4t is mass flow and potential thrust can be calculated taking into account jet nozzle sizing and jetpipe temperatures ...............all things are interconnected with a turbine engine as theres no "valves" in the system to isolate one part from another .

Cheers
John

Are you some kind of rocket scientist? 

My thoughts for measuring fuel consumption, I would think that as the density of the fuel increases, so would the force that it imparts on the float.  Not really important though, I can also use a scale on the tank and watch its rate of fall.  Then again, measuring fuel consumption doesn't seem to be that necessary.

When you say P4t, how would you built the pitot?

So, here is what I am thinking:

0-100 PSI gauge for oil supply
0-30 or 0-50 PSI for P2
0-50 PSI for P3

[turboron]

hosedup, the fuel flow is needed to estimate the air mass flow which you need, along with pressure ratio, to plot a point on the compressor map. In other words, the mass flow is a key thermodynamic number need to determine the engine performance.

Thanks, Ron

[racket]

Go for a 50 psi P2 gauge for P2 , for a good sized engine 30 psi isn't enough .

The pitot need only be a bit of bent tubing with the inlet pointing towards the turb wheel

[arthuro]

Hi Guys,
I was wondering something.
Is it useful to measure P3?

and for T2, i did not see anybody taking a measurements of it on there projects.
So actually my question is:
What is important to measure?

I like to measure T2 for sure. Do i need to take friction into account? I can just weld a small pocket in the compressor tube so there is only slow moving air.



For example racket i only see you measuring TOT and P2, for the rest i can not read it from the picture.

Arthur

[racket]

Hi Arthur

P3 could be a tad hard to measure , I generally assume a 5% pressure drop across the flametube , so P3 = P2 X 0.95 .

Yep I measure T2 minus T1 to get the temp rise across the comp to work out comp efficiency , I also measure P4t using a pitot tube in the jetpipe, a very useful reading to have as its the jetpipe temps and pressures which ultimately produce the velocity from the jetnozzle . .

Checkout the vids and pics on this page jetandturbineowners.proboards.com/thread/612/fat-boy-118-thrust-engine?page=114

Cheers
John