Just a thought... what do you think?

Anyone fiddled around with IR radiometry detectors? Are they fast enough to line-scan the rotor face temp with a reasonable accuracy?
How about an IR camera? Too slow?
Where to put metering holes? can the array be fit somewhere into port or do we disutrb the inflow too much? Can we see edge areas also from

p-port?

Row of discreet holes better? Apex oil gets in, how to cover 'em?

Instrumenting the rotor itself is a bit tricky, so this would give comparatively easy way to measure rotor face temp as mixture sees it - on the fly...

And... by correlating those IR measurements with some kind of in-rotor temp measurement run would give a pretty good idea what's going on on combustion chamber and rotor metal, temp-wise.

Cheers,

Petri



Q Anyone fiddled around with IR radiometry detectors?

     Yes, I worked for a firm called Electro-optical industries for several years, they supplied the military, aerospace and research industries with infrared blackbodies and specialized IR instrumentation.



Q Are they fast enough to line-scan the rotor face temp with a reasonable accuracy?

     do you have a specific sensor in mind? Most of those I'm familiar with are not high speed devices. A lot depends on the nature of the data you need to collect. As I'm not an expert in internal combustion engines, you would have to quantify "fast enough" and "reasonable accuracy". First you need to define your performance requirements, temp range to be measured, degree of accuracy, time interval, etc.

Q How about an IR camera? Too slow?

In a laboratory setting or what kind of installation? IR cameras are not cheap, price is dependant on resolution, measurement range, detector speed..... Then there is the tooling and adapters for the application. All would likely be custom fabrications.

Q Where to put metering holes? can the array be fit somewhere into port or do we disturb the inflow too much?

Dunno, would have to know which sensor is used first. I'm thinking a pyrometer kind of device would be more practical, less expensive, easier to implement.
All depends on your measurement specifications, degree of accuracy, etc.

     C. Smith

Thanks C

Paul Lamar

Ok, let's try to make some specs. If you find something wrong here please
correct.

1. How fast? -> sampling rate
Let's take two speeds as a basis: 6000 rpm and 12 000 rpm. That's shaft
speed, and rotor turns 1/3 of that speed, having 3 faces, so each rotor face
pass lasts:
6000 rpm: 1/100 sec. ie. 10 msec
12 000 rpm: 1/200 sec. 5 msec

If we need at least 10 samples per face, and preferably 20, we will get:
6000 rpm: 1kHz to 2kHz sampling rate
12 0000 rpm: 2k to 4k sampling rate

2. What's the temp range?

According to that image that Paul has posted previously (see attachment),
145- to 190 deg C
418- to 463 deg K
293- to 374 deg F
753- to 834 deg R

#Max IR radiation is thus:

M (W/m2) = e*s*T^4 (e=emissivity 1.0 to 0, s=sigma=Boltzmann's constant)

Emissivity of cast iron is anything between 0.07 to 0.28, thus:

M = 25.1 * emissivity -> M = 1,75 W/m2 to 7,02 W/m2


#Max IR wavelength
curve is quite flat on this temp area, Max IR wavelength is (Wien's transfer
eq.)

L (wavelength, metres) = b/T (b=wien's displacement constant, T=kelvin)

L1 = 2.897E-3 / 418 K = 6921 nm
L2 = 2.897E-3 / 463 K = 6248 nm

3. What's the required accuracy?

I think we are, initially,  mostly after trends here, so +/- 5 deg C is
something we can live with.

4. Where to put sensors, and how?

I think that one working solution (works both 13b and 13 MSP/renesis) is to
drill a row of holes between induction side chamber crest and mixture inlet.
Seals are easing there after crest, so mechanically and temperature-wise it
seems rather uncomplicated place.

But... are eg. glass fibers opaque on thermal IR range? What to use instead?


Cheers,

Petri


Thanks for making the definition of specification there Petri. I appreciate
your thoroughness in providing all the foreseeable conditions. Is this to be
used in a dynamometer lab? What kind of Data collection equipment is
available, or associated with the test cell? Who manufactured it, Schenk?
GE? Someone else? Are we constrained by available collection equipment, or
can we add to it? O-10V input, 4-20ma? Bridge type signal amplifier?
I have a lot on my plate with 2 classes this semester in addition to my full
time job with a 126 mi daily commute. If this is a serious request for an
actual project for the group I will put some effort into researching an
adequate sensing device. If this is just a mind exercise, then I would ask
that those interested in the answers use the data provided to find out for
themselves.
Please let me know what is at stake here.
C. Smith