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Testing and Benchmarking Discuss, design, and debate ways to evaluate the performace of he goods out there. |
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11-02-2005, 05:26 PM | #101 |
Cooling Savant
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I'll have a reread of that book (its 1000 pages long) i could of mis read and such.
The dt from wcooling rads is exceptionally low this effects things alot. I have a feeling that i might be wrong about this eff thing but i will have a look. Some more extrapolation form bills results maybe need as energy disipated looks low and results need to be filled. I could of made an algerbra error as my maths as gone cack. |
11-03-2005, 01:12 AM | #102 |
Cooling Savant
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Maybe can be rationalised if consider airflow's Velocity rather than Volume rate
Possibly a universal graph for Effectiveness vs Velocity can be produced Attached revamped Post 58 Graph2&3 (m/s=(1.22 >>1.3)xm^3/min) Very unsure whether is universal as regards radiator area and volume. Car Radiator zone is that investigated by Delphi Possibly,with quieter engine development(dunno whether electric vehicles have a rad), the car radiator industry will further enter the PC zone Dunno how realistic Zones are. Last edited by Les; 11-03-2005 at 06:02 AM. |
11-03-2005, 06:09 AM | #103 |
Cooling Savant
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That could well be the case.
A large differential between Cair and Cwater is going to result in very high design efficantcies i suppose. Anyway it kind kills using eff as a number, perhaps this is what delphi was talking about in their paper. |
11-03-2005, 06:16 AM | #104 |
Cooling Savant
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Or perhaps,unfortunately,opens the way for its abuse by the unscrupulous
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11-07-2005, 02:39 AM | #105 |
Cooling Savant
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Deleted
Or have I screwed-up,Bobo? Edit: Deleted = think have screwed-up. Will rethink Last edited by Les; 11-07-2005 at 03:05 AM. |
11-07-2005, 04:28 AM | #106 |
Cooling Savant
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ur alright just ive got alot work on (Mckinsey interviews n stuff) so cant post alot goign to have a read of the heat exchanger book on the train.
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11-07-2005, 07:33 AM | #107 | ||
Cooling Savant
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Bobo
Deleted contained big boob and has lost its attraction. Was suggestions re " Quote:
Quote:
Deboobed amounts to little more than specimen 4 Temperatures(Tai,Tao,Tci,Tco) checks at Low((say 20cfm(0.57m^3/min)) and High ((say,130cfm(3.68m^3/min)) fan ratings with Low(1lpm) and High(10lpm) coolant flowrates. Thoughts are welcome Bobo. However has lost its attraction due to complexity. The Crunch is that any verification efforts would be solely Bill's toil How difficult would be it be experimentally, Bill?" Why should the onus always fall on Bill, all? Last edited by Les; 11-07-2005 at 07:39 AM. |
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11-07-2005, 09:01 AM | #108 |
CoolingWorks Tech Guy Formerly "Unregistered"
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worms for breakfast
the test is to determine the correction factor for the hydraulic resistance of the cross plus 6" of tubing used for the instrument and DUT connections for the test shown the coolant and the ambient were held as close as possible (0.3 to 0.45°) the connection correction for pressure drop is typical, the flow effect is puzzling to preclude some of the obvious; 1/3 DIN RTDs individually/simultaneously caled with their inst using a quartz ref thermometer and a bath (bath thermal pattern cked) am rerunning for more accuracy, then will reverse to ck will try a larger tee to drop the velocity around the RTD tip ?? EDIT units should be lpm in temp 'corr' graph Last edited by BillA; 11-07-2005 at 09:06 AM. Reason: graph axis units mislabeled |
11-07-2005, 09:16 AM | #109 | |
Cooling Savant
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Quote:
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11-07-2005, 09:30 AM | #110 | |
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didn't I just get shelled for my lack of objectivity ? bench moving along Marci, debugging is a pain, building confidence longer |
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11-07-2005, 10:27 AM | #111 | |
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if frame of reference is continually to be the original ThermoChill data, then logic states (to me) testing of further theories in line with that is all done by the same person that produced the original data if only for consistency purposes (assuming current testrig results can be compared satisfactorily to the test rig used originally)... others then need to test to confirm methodology across other platforms / testrigs... |
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11-07-2005, 11:34 AM | #112 |
Cooling Savant
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Cos Bill can be arsed?
Bill what exactly are you saying? Some nice scribbles would be good. |
11-07-2005, 11:56 AM | #113 |
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post #108
saying that I'm measuring a delta T related to flow, w/o dissipation (independent of amb/ext temp) the delta T is negative; and while I have a passing notion about frictional heating and pressure drop, am stumped explaining a 'substantial' temp drop - this is an experimental issue I suspect ?? more scribbles re your question ? |
11-07-2005, 12:21 PM | #114 |
Cooling Savant
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I mean a scribble of your appartus so i can see what it is happening to. Paint doodles will do. 108 is a very les style post cant see exactly what you are talking about.
Is it a well insulted setup? As the tubing could be cooling stuff down. |
11-07-2005, 12:24 PM | #115 |
Cooling Savant
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Would go along with "experimental issue". turn a blind eye and wait for someone else to resolve.
Unfortunately there is no-one else and you have to resolve. Have you tried prayer or incantations? Ignore below Had wrong picture,rectified by Post 116 Know nothing, but thinking along lines of flattening of T gradient across section with ^ Reynolds. Last edited by Les; 11-07-2005 at 12:49 PM. |
11-07-2005, 12:38 PM | #116 |
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insulated ? the DUT is in a environmental chamber, in this case set to the 'same' temp as the coolant
the DUT is 6" of 3/8"ID silicone tubing having a cross connected to each end, for both crosses one branch is for a 1/4" RTD and the other a pressure tap - the pressure drop across this DUT will equal the 'connection pressure drop' which is subtracted from the gross readings of other devices - likewise the strange temperature drop measurements but I think not, some other issue - not new physics |
11-07-2005, 02:37 PM | #117 | |
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Appears negligible (attachment) Rather mystified with your pressure drop units. mA=milli-atmospheres? Taken as such and equated roughly as millibar. But does not matter |
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11-07-2005, 03:52 PM | #118 |
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the dP xmtrs have a 4 - 20mA output over their span range
y (in.H2O) = 31.25x-125 larger tees to be tested now |
11-07-2005, 04:41 PM | #119 |
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Corrected graphs
dT still small Larger Ts Could always give worse results - if related to flattening of T gradient across section with ^ Reynolds Edit3: 3rd time lucky with attachment(I hope) Last edited by Les; 11-08-2005 at 11:15 PM. |
11-10-2005, 12:38 AM | #120 | |
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Quote:
Edit: Some words. Think: 1) True SD varies as broached in Post 71 (probably small) 2)Delphi are observing difference between "Inferred" and Characteristic" but inappropriately(GIGO) analyzing using a CFD version of Post 71 . 3) "True SD", "Inferred SD" and "Characteristic SD" can all be used to describe radiator(If can calculate then are a properties). 4) Think approach of increasing "Set Temperature Differential" with decreasing SD(adopted by Bill for Swiftech's 80mm QP rads), is theoretically sound as well as experimentally sound . Last edited by Les; 11-10-2005 at 02:43 AM. |
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11-10-2005, 08:59 AM | #121 |
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some data tomorrow ?
lots of compression, and an offset, not addressed in all past data (so sorry) a shame I cannot/will not talk with Stephen as he has the only other test bench and how can I help a co that is stiffing me for $60k in past due wages ? |
11-10-2005, 02:40 PM | #122 | |
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11-11-2005, 03:44 PM | #123 |
Cooling Savant
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Possibly the onus is on zytrahus to lurk here
Maybe inherent in his job description Data today ? |
11-11-2005, 07:49 PM | #124 |
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having promised some data, . . . .
here is some describing the search for reality in calibrating a new test bench with commercial equipment, as contrasted with Incoherent rolling his own For temps I started with some Keithley and Fluke RTD thermometers with 0.01C resolution, to which I added some ¼” 1/3 DIN B tol 4-wire sensors. Sent it off to the cal shop and got them back with nice certs, which did not seem to jive too well with my comparisons. So I accepted the thermometers as being ‘in spec’ per the certs, but would have to recal for more accuracy using a Haake A82 recirculating chiller with a HP 2804A quartz thermometer with 2 probes. The bath was ‘mapped’ and the probes then caled and cross checked, with the results shown in the RTD cal graph. (Thanks for the help Les) essential to this activity is the mapping of the bath at higher resolution, and the consistency The next task was to quantify the head loss of the instrumentation fittings and the connecting tubing to the DUT. The crosses are (now) as shown in the photo, but were connected together for testing with a single piece of tubing. Using the 823DP data, a head loss curve was developed, but a temperature anomaly was noted; there was an ‘apparent’ temperature drop across 6” of tubing with no temperature difference between the coolant and ambient. The connection temperature offset graph shows several crosses tested several ways, and my first inclination (and action, alas) was to use the Series 5 data as an offset of 0.054°C; more reflection suggests that the Series 4 equation is a better description. temp related stuff is delayed ‘till I redo the spreadsheets, etc. the cross head loss is as shown, but will be redone at a higher flow resolution of 0.001gpm. so at the moment all I have is a head loss curve for the CoolingWorks CoolRad-12T more later BTW, "C" will be coolant inlet less air inlet |
11-11-2005, 08:17 PM | #125 |
Cooling Savant
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ah my head is going to hurt again.
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