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Post by racket on Sept 11, 2022 0:35:00 GMT -5
Hi Chris
Nope , no slippage , marks still in alignment and Loktited between nut and wheel , the bore is tapered , OK at the front , bigger at the rear , classic stressing .
Because the wheel is "weak" , its probably been designed for a modest boost where it'd be OK , probably anything up to 30 psi boost and there wouldn't be any problems .
Theres a couple of KTS wheels I'd be looking at , their D171 and D162 , both have reasonable in to out area ratios and 45 degree exducer trailing angle for "flexibility" and hopefully good efficiency .
LOL, and I thought I'd just about finished development :-(
It'll be interesting to see what difference just a wheel change will make .
Cheers John
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Post by finiteparts on Sept 11, 2022 22:26:08 GMT -5
Well, that is a bummer that they weren't up to snuff. There really was no way to tell till you tested them.
I got the impression that you compressor efficiency has reduced from prior runs. That is why I thought maybe it had some slipping. Since that is not the case, what do you think might be penalizing your compressor performance?
At least the KTS impellers should be better for higher performance since they claim to be made from Alcoa 2618 and they provide a quality cert on that.
Is the discharge angle similar to what you had, i.e. will you have to modify your diffuser entrance angles?
Good luck,
Chris
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Post by racket on Sept 11, 2022 23:30:07 GMT -5
Hi Chris
Some of my earlier tests were a tad "hurried" and I probably didn't let T2 settle long enough before changing power setting , this latest test was strictly for checking comp effic. using 3 thermocouples
The old wheels had a 70 degree discharge , the KTS ones at 45 degrees will mean a diffuser "adjustment", hopefully I can juggle the radial air velocity through channel height changes so as to match the vane tip angle , ..........fun times ahead :-(
The TF15 wheels from KTS are mainly machined from 7075 for some reason
Cheers John
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wyldon
Member
Joined: August 2022
Posts: 13
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Post by wyldon on Sept 18, 2022 7:53:50 GMT -5
Hi Chris Nope , no slippage , marks still in alignment and Loktited between nut and wheel , the bore is tapered , OK at the front , bigger at the rear , classic stressing . Because the wheel is "weak" , its probably been designed for a modest boost where it'd be OK , probably anything up to 30 psi boost and there wouldn't be any problems . Theres a couple of KTS wheels I'd be looking at , their D171 and D162 , both have reasonable in to out area ratios and 45 degree exducer trailing angle for "flexibility" and hopefully good efficiency . LOL, and I thought I'd just about finished development :-( It'll be interesting to see what difference just a wheel change will make . Cheers John What sizes are the D171 and the D162? Looked on their site and other than a spreadsheet longer than the English Dictionary I couldn't find much.
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Post by racket on Sept 18, 2022 16:54:13 GMT -5
127/175mm slightly different axial sizes between the two wheels , the D171 would be my preference as its axial dimensions are closer to what its replacing
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Post by racket on Oct 5, 2022 19:32:08 GMT -5
Hi Guys Been a bit quiet here on the Forum , ain't nobody doing nuthin' Whilst waiting for the new wheel I've made up a proper P2/T2 sensor . Its fitted through the front comp cover into one of the diffuser channels near the "corner" , theres a large hole subjected to ram air and a small hole at the rear further down the "tube" so that the stagnated air can escape after passing the T2 thermocouple , the P2 is delivered to a fitting on the outlet of the tube. This will hopefully provide more accurate readings for calculating comp efficiency Cheers John
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praendy2203
Veteran Member
Joined: August 2020
Posts: 160
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Post by praendy2203 on Oct 7, 2022 15:34:03 GMT -5
Hi John, I am working, but very slowly at the moment. Ordered a 11 Kg chunk of stainless for the outer part of the new ngv. 90% will be lost again and converted into blue chips😁 I post some pics here. 9 vanes to go and the inner part is ready for welding. Andy
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Post by racket on Oct 8, 2022 0:51:56 GMT -5
Hi Andy
Great to see theres someone creating something
Thats going to make a big difference to your engines operation, I think you'll be pleasantly surprised by the thrust increase .
Love the wooden positioning jig , I like using wooden jigs, easy to make and yet do a great job of aligning bits into position when we don't have enough hands to hold and weld at the same time :-)
Cheers John
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Post by racket on Nov 17, 2022 21:56:11 GMT -5
Hi Guys Its arrived I'll spend the weekend measuring everything up on the wheel so that I can get an idea of what mods need to be made to the diffuser Interesting curves on the blades with the point milling vs flank mill A race horse compared to a cart horse Cheers John
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Post by racket on Nov 18, 2022 1:05:59 GMT -5
Hi Guys
She's lightweight at 865 grams compared to the old wheel at 1317 grams, everything is thinner .
Inducer has a rather "high" angle at the tip of ~34 degrees , and inducer throat area is ~10% greater than old wheel .
Exducer angle is a tad confusing as they advertise 45 degrees , but it looks more like 60 degree, actual tip height of passageway is 9.5 mm , advertised 11mm but with 1.5mm backwall added in .
Superback is 11mm compared with only 6mm of previous wheel so it shouldn't allow the bore to stretch .
So far its looking good , hopefully once I try fitting it to the comp cover I won't run into problems
Cheers John
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praendy2203
Veteran Member
Joined: August 2020
Posts: 160
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Post by praendy2203 on Nov 18, 2022 14:04:27 GMT -5
Hi John,
Two months waiting for a nice wheel😊
At least you got it and can start again at the front end of the engine.
Hope to see it running soon😁
Andy
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Post by racket on Nov 18, 2022 15:51:13 GMT -5
Hi Andy
Yep , its been a bit of a wait , but I can get back into it again .
I'll have a look at whats required at the comp cover shroud today, hopefully not too much machining , don't know if the surge slot will need "work"
Cheers John
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monty
Senior Member
Currently being spanked by mother nature.......
Joined: September 2018
Posts: 399
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Post by monty on Nov 19, 2022 10:51:48 GMT -5
Nice looking wheel! I've wondered about the new point milled designs. I've read a few papers looking at inducer sweep. IIRC forward sweep was considered "better" than aft sweep, but I think that was based on CFD...so who knows. It will be interesting to see what the comp efficiency is compared to the old wheel. Too bad the exducer ht isn't the same.
I've been working on 5 axis stuff. Made the first fixture I need for machining the gear case foam. Still learning the CAM software. None of it very exciting so I haven't posted anything.
Monty
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Post by racket on Nov 19, 2022 17:26:30 GMT -5
Hi Monty
Exducer height is better for higher pressure ratios , the "in/out ratio" between inducer and exducer is ~2.4 :1 , so made for it :-)
I've started machining the front cover and have been able to get a reasonable curvature shroud shape , but because of the slightly smaller inducer , 127mm vs 128 mm , I'll be running extra clearance at the front which won't be a major concern as long as the compression producing part of the wheel has a close clearance .
I'll need to remove ~3mm off the diffuser vane heights , gotta do some maths first to be certain the air angle is compatable .
The point milling certainly produces better shapes , shame that it takes twice as long to machine a wheel , it gets expensive :-(
LOL, I'll leave learning the 5 axis stuff to brighter minds than mine, I'm afraid I'm getting on "the wrong side of the curve ".
Cheers John
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Post by turboron on Nov 20, 2022 8:55:47 GMT -5
John, I agree that once you pass 75 you are definitely on "the wrong side of the curve". My thought is that "I am running out of runway".
Thanks, Ron
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