Blocked loader question

[PC Rat]

Does the shape of the blocker directly effect lift?
In other words, does a v-blocker create more lift than a flat blocker?
Brian

[Squirtin Thunder]

Does the shape of the blocker directly effect lift?
In other words, does a v-blocker create more lift than a flat blocker?
Brian
Going off what you have said, I would say a flat blocker would give more lift. Because a Vblocker will go through the water more like a knife than a flat rock skipping across the pond.
Jim

[flat broke]

I'm going to go out on a limb and say that the shape/orrientation of the blocker has less to do with lift, and more to do with the amount of water, and how the water is kept away from the impeller. Each design will create different turbulence which may be more/less advantageous in different applications.
Chris

[LVjetboy]

I'd guess the shape of the blocker has less to do with lift than the blocker angle (orientation?) and total blocker surface area. Total blocker surface area the dominant lift factor no matter the shape. I'd also guess shape has more to do with lateral pressure distribution at the blocker release point.
Just guesses.
What would be really interesting is to have a 360 degree array of pressure sensors near the impeller inlet flow. Then change loader designs and see what happens. This is not hard to do...just needs someone to do it.
jer

[jweeks123]

What would be really interesting is to have a 360 degree array of pressure sensors near the impeller inlet flow. Then change loader designs and see what happens. This is not hard to do...just needs someone to do it.
jer
just needs someone to pay for it :smile:

[LVjetboy]

just needs someone to pay for it
True enough. But you'd think some forward-thinking pump mfg would use those limited resources to measure? I can tell you the probes required and the data aquisition unit are not a freakin' big hit to an R&D budget. Or outweight the potential advertising benefit of "tested" results. Hook up some goverment surplus transducers and calibrate them. Then run tests and publish. You think HBM won't run that article? Or is it all on us jetters to pay for everything?
jer

[djdtpr]

I am with everyone else i dont think the v blocker will have any difference in lift then a flat blocker,but the water placement definatly would be different.

[roostwear]

What would be really interesting is to have a 360 degree array of pressure sensors near the impeller inlet flow.
If someone DOES do it, I want to be there with the camera to document the housiing cracking in half.

[Squirtin Thunder]

Thats it I am calling Jack !!!!!

[WheelerDealer]

A dimpled air-bearing loader would be the way to go! Sorry guys, I couldn't help it. Carry on.

[Squirtin Thunder]

A dimpled air-bearing loader would be the way to go! Sorry guys, I couldn't help it. Carry on.
Smart Ass !!!

[Fogged Gullwing]

I think Jer's right on here. R&D is the key, Jack even told me to experiment with the loader he sold me. Every boat is different so try it out if your game!! Or in my case put a bigger N2O jet in it!!! or in DJ's case a smaller pulley!! :2purples:
Later BK

[djdtpr]

I think Jer's right on here. R&D is the key, Jack even told me to experiment with the loader he sold me. Every boat is different so try it out if your game!! Or in my case put a bigger N2O jet in it!!! or in DJ's case a smaller pulley!! :2purples:
Later BK
no smaller 18 lbs is good enough for me.Maybe a small shot of nos though just to add a little zip.

[LVjetboy]

"If someone DOES do it, I want to be there with the camera to document the housiing cracking in half."
If the intake cracks in half from six or so pressure taps then maybe the intake's not designed with an adequate safety factor? It could happen, but unless someone records pressure distribution across the impeller face, then all this loader design thing is guesses and endless trial and error.
jer

[Squirtin Thunder]

no smaller 18 lbs is good enough for me.Maybe a small shot of nos though just to add a little zip.
Danny,
A little zip ??? Yah right !!!!
I am looking forward to seeing your new zippy boat !!!
Jim

[Fogged Gullwing]

just needs someone to pay for it
True enough. But you'd think some forward-thinking pump mfg would use those limited resources to measure? I can tell you the probes required and the data aquisition unit are not a freakin' big hit to an R&D budget. Or outweight the potential advertising benefit of "tested" results. Hook up some goverment surplus transducers and calibrate them. Then run tests and publish. You think HBM won't run that article? Or is it all on us jetters to pay for everything?
jer
Of course Jer we have to pay for everything!!! How can I mount my 10.2 Ghz P11 processor with 50 gig of ram and my raid 111 200 terabyte drives. to my jet pump? They only taught me so much at the farm!!! :220v:
Later BK

[Squirtin Thunder]

Of course Jer we have to pay for everything!!! How can I mount my 10.2 Ghz P11 processor with 50 gig of ram and my raid 111 200 terabyte drives. to my jet pump? They only taught me so much at the farm!!! :220v:
Later BK
Now thats funny !!!!

[corlish]

[QUOTE=
What would be really interesting is to have a 360 degree array of pressure sensors near the impeller inlet flow. Then change loader designs and see what happens. This is not hard to do...just needs someone to do it.
jer[/QUOTE]
Jer, this would certainly add to the body of knowledge -- but it would only give you wall pressure -- that may helpful but could also be misleading. Almost always the interesting things happen at some place other than along the wall. This goes back to the CFD discussions a while back on the RJB board. In my mind to truly understand what's going on in and around the intake someone needs to do a CFD analysis. I would love to as I have free access to FLUENT right now -- just don't have the time with thesis, work, kids, and etc.
I am confident that Jack, Duane, and others who have been fooling with this stuff for a long time have some intuition about the pressure distribution within the intake (not just along the wall).
Corey

[Squirtin Thunder]

Thats it I am calling Jack !!!!!
I will call Jack Monday !!!!

[Cs19]

Jer, this would certainly add to the body of knowledge -- but it would only give you wall pressure -- that may helpful but could also be misleading.
In my mind to truly understand what's going on in and around the intake someone needs to do a CFD analysis. I would love to as I have free access to FLUENT right now -- just don't have the time with thesis, work, kids, and etc.
Corey
Whats involved in a CFD analysis? Is it something we could do with our Edelbrock data aqusitions ? Or does it require some special insturments?
I dont think its uncommon for guys to pull 2 readings off the inlet, top and bottom.

[corlish]

Whats involved in a CFD analysis? Is it something we could do with our Edelbrock data aqusitions ? Or does it require some special insturments?
I dont think its uncommon for guys to pull 2 readings off the inlet, top and bottom.
CS -- no the Edelbrock would not do the job for ya. Since I did not spell the acronym out, I am not sure who all knows what it is ... Computational Fluid Dynamics generally speaking is a method of using a computer to approximate a solution to the Navier Stokes equations (they pretty much describe all aspects of fluid flow in any geometry). What is needed is a fairly high end workstation, a very expensive piece of software, and somebody who knows how to use it. It's kind of like MIG welding -- it is very easy to get good looking results but also just as easy to get it all wrong.
Back to the wall pressure thing -- a reading of 20 psi at the wall is just that it is at the wall -- what is it an inch out into the suction housing?, two inches?, near the pump shaft?
At least the folks who have been around this stuff for awhile have an empirical knowledge base -- they know what wall pressure (or range of pressures) at a specific point gives good results. A CFD analysis would predict what the pressures are throughout the entire suction housing under a specific set of conditions. The only other way that I know to do this (and obviously not pratical) would be to have a series of test ports that a pitot could be inserted into at various depths and come up with a "pressure map".
What could be gained from this? Honestly, I don't know -- my guess is not much but it is possible there is a golden nugget to be found -- possibly a different method to keep pressure above NPSH -- just rambling at this point :confused:
Corey

[LVjetboy]

"Of course Jer we have to pay for everything!!! How can I mount my 10.2 Ghz P11 processor with 50 gig of ram and my raid 111 200 terabyte drives."
My point was, if a racer or one of us can afford data acquisition, then why not a pump mfg??? Some say it's all about profit margin. I say ok, that and maybe motivation or passion of those who run the company and want to be forward thinking. They are lacking. If they had that passion? Maybe profit would follow. If a racer or lake boater can spring for data acquisition then why not a major pump mfg???
Maybe that's real funny!
"Jer, this would certainly add to the body of knowledge -- but it would only give you wall pressure"
When I originally posted, "a 360 degree array of pressure sensors near the impeller inlet flow" I wasn't suggesting just static pressure sensors. Dynamic at mid flow can be measured too, if not exclusively. My guess is, mid flow dynamic maybe more representative of impeller inlet conditions than wall static.
"Whats involved in a CFD analysis?"
Just to set the record staight, I'm not a CFD junkie or think CFD can cure the worlds technical problems. I've been involved with CFD and I think I have a realistic view of both the benefits and limitations of CFD. And in this thread I ONLY suggested experimental data acquisition of the pressure distribution across the impeller inlet NOT CFD...for a good reason...cost and payoff.
But how expensive a couple of probes and DA? Especially for say, Berkeley mfg?
jer

[flat broke]

^^^^^ For that matter, one of many race boats that may be sponsored via contingency programs by say Aggressor? Any of those guys running DA equipment? Perhaps Aggressor could kick down additional contingency money in exchange for racers using one of their suction housings and a DA setup. They could have a couple suction housings tapped for sensors, and rotate them through different HP levels of boats.
Since a local distrubutor would probably implement the program on a local level with Aggressor's support, that local shop/distributor would then also get access to the information. Sounds great, everyone gets something out of the deal, and everyone should be happy, right?
I don't run an Aggressor Impeller in my setup, but since they claim to be on the forefront and making improvements to overall pump efficiency, they seem like the best fit for such a program... That and the fact that as far as I know the rest of the mfg's don't offer contingency programs and don't interact directly with racers (excluding the whitewater scene).
Speaking of which, those guys are probably more apt to get something like this off he ground. Because of the sensitivity of their pump loading and reliance on the shape of the spoon area in front of the intake, they'd probably just as interested if not more so in this kind of information. It also seems like a better fit when you look at companies making billet suction housings, and guys willing to spend the extra $$ to go the extra mph. People in that segment of the idustry do invest into their infastructure, so maybe its the better segment to try something like this in.
Chris

[corlish]

"Jer, this would certainly add to the body of knowledge -- but it would only give you wall pressure"
When I originally posted, "a 360 degree array of pressure sensors near the impeller inlet flow" I wasn't suggesting just static pressure sensors. Dynamic at mid flow can be measured too, if not exclusively. My guess is, mid flow dynamic maybe more representative of impeller inlet conditions than wall static.
jer
What type of sensor (mounted at the wall) measures pressure elsewhere (without being exotic i.e. doppler, laser velocimetry, etc) -- are you talking about probes at fixed lengths?
Corey

[LVjetboy]

"are you talking about probes at fixed lengths?"
I was talking something like a pitot tube extending into the midpoint of the flow at least six points around the circumference. Not that that's everything. Yes a static wall tap gives some information. If drilled and mounted right. But I'd think midflow dynamic may give a bit more representative info and more clean flow? At least a BETTER idea of impeller face loading? How hard or expensive is that? Duh. What does Aggressor think? Have they done this? If so give us the data.
jer

[steelcomp]

I'm curious as to what you'd do with the info? Are we assuming that the optimum would be to have equal pressure at the face of the impeller? Is this across the entire face, or is it just at the outside, or closer to the center? Or do you think there should be different pressures at different places of the impeller? Do we know what's ideal for sure? How do we expect to get equal pressure at the impeller (if that's the goal) when the water is traveling differend distances and speeds at any given point in the intake? Is the loader trying to compensate for the short and long turn in the intake? What about how the shaft spinning at different rpm's effects the pressure?
Just curious.

[flat broke]

I'm curious as to what you'd do with the info? Are we assuming that the optimum would be to have equal pressure at the face of the impeller? Is this across the entire face, or is it just at the outside, or closer to the center? Or do you think there should be different pressures at different places of the impeller? Do we know what's ideal for sure? How do we expect to get equal pressure at the impeller (if that's the goal) when the water is traveling differend distances and speeds at any given point in the intake? Is the loader trying to compensate for the short and long turn in the intake? What about how the shaft spinning at different rpm's effects the pressure?
Just curious.
I'm going to go out on a limb and say that once you had a good base of data with different HP/RPM/Loader designs, you could start to model the changes without actually building them. Don't know though as this stuff is above my league of knowledge. Only speculation on my behalf.
Chris

[Fogged Gullwing]

Jer,
I live for data aqusition!!! When I started my dyno business in 95 I bought every pressure and temp tranducer I could buy! When I started out in DA it was in the early 80's when we had 8 Bit hexadecimal HP 1000 computers that you had to manually load stuff into! When Gates introduced windows we were all looking at windows 3.1 with awe!!! I used to work for a company called industrial computer designs in 1981 that used to make DA ISA cards back then and I thought that was the shit!! In 1990 I worked on some true digital and analog stuff and was stunned by the leap of technology. Alot of people are scared of it and thats just fine with me !!! Just gives me a bigger advantage! Walk thru the Jet boat guys pits and you will see guys like Jack & BP sitting with their laptops instead of having wrenches in their hands!!
That's where I'll be!!
Later BK

[LVjetboy]

"I'm curious as to what you'd do with the info? Are we assuming that the optimum would be to have equal pressure at the face of the impeller? Is this across the entire face, or is it just at the outside, or closer to the center? Or do you think there should be different pressures at different places of the impeller? Do we know what's ideal for sure? How do we expect to get equal pressure at the impeller (if that's the goal) when the water is traveling differend distances and speeds at any given point in the intake? Is the loader trying to compensate for the short and long turn in the intake? What about how the shaft spinning at different rpm's effects the pressure?
Just curious."
Good questions. One at a time...
"I'm curious as to what you'd do with the info?"
I'd compare performance changes to pressure data then draw conclusions.
"Are we assuming that the optimum would be to have equal pressure at the face of the impeller? Is this across the entire face, or is it just at the outside, or closer to the center?"
Not necessarily. My guess; optimum pressure is a pressure that avoids flow separation...that depending on local flow velocity, pressure and airfoil or blade angle to flow direction. So maybe not equal pressure, but pressure that eliminates flow separation. And that depends on where on the face you measure.
"Or do you think there should be different pressures at different places of the impeller?"
Most likely. As I said above. But with a mid-flow probe I think there's a better chance of measuring significant data and preformance trends than with just a static intake surface probe.
"Do we know what's ideal for sure?"
Or course not. That's the value of testing or experiment. But testing in the right place. Intake surface static pressure can show trends but has the limitation of measuring within the boundary layer. Mid flow pressure may be more representative of overall impeller intake conditions. Not perfect but maybe a better representation of average flow than surface static.
jer

[Squirtin Thunder]

"I'm curious as to what you'd do with the info? Are we assuming that the optimum would be to have equal pressure at the face of the impeller? Is this across the entire face, or is it just at the outside, or closer to the center? Or do you think there should be different pressures at different places of the impeller? Do we know what's ideal for sure? How do we expect to get equal pressure at the impeller (if that's the goal) when the water is traveling differend distances and speeds at any given point in the intake? Is the loader trying to compensate for the short and long turn in the intake? What about how the shaft spinning at different rpm's effects the pressure?
Just curious."
Good questions. One at a time...
"I'm curious as to what you'd do with the info?"
I'd compare performance changes to pressure data then draw conclusions.
"Are we assuming that the optimum would be to have equal pressure at the face of the impeller? Is this across the entire face, or is it just at the outside, or closer to the center?"
Not necessarily. My guess; optimum pressure is a pressure that avoids flow separation...that depending on local flow velocity, pressure and airfoil or blade angle to flow direction. So maybe not equal pressure, but pressure that eliminates flow separation. And that depends on where on the face you measure.
"Or do you think there should be different pressures at different places of the impeller?"
Most likely. As I said above. But with a mid-flow probe I think there's a better chance of measuring significant data and preformance trends than with just a static intake surface probe.
"Do we know what's ideal for sure?"
Or course not. That's the value of testing or experiment. But testing in the right place. Intake surface static pressure can show trends but has the limitation of measuring within the boundary layer. Mid flow pressure may be more representative of overall impeller intake conditions. Not perfect but maybe a better representation of average flow than surface static.
jer
LVjetboy (Jer),
Does it hurt when you think that hard ???
Very Good answers !!!
Merry Christmas
Jim

[UBFJ #454]

Jer's right about the location of the Intake Pressure Sensor ... We've chosen to sense our Intake Pressure 1/2 way up our Dominator Suction Piece ... Felt that was the best location to get away from effects of both the Intake/h2o Boundary and the Face of the Impeller.
A comment about interperting intake pressure data if your using different Loaders as we do in Racing ... I can clearly see the effects of different Loader Designs in the data ... The position of the horizontal 'Stingers' of a loader relative to the sensor must be taken into account when interpreting intake pressure data ... Example, the closer the stingers are to the sensor, the higher the pressure measured ... This may not mean that the intake is being fully "loaded" cause, it may not be. If your only using one loader then it doesn't matter that much because the changes you see will be primarily from your hardware changes ... Unless the stingers are too awfully close, then all data will be bogus ...
Just something to keep in mind ... Loader Stinger Position(s) Relative To Your Sensor(s).

[steelcomp]

It seems to me that because of the constant dynamic conditiond found inside the intake and across the face of the impeller, you'd need hundreds of sensors at strategically chosen positions to actually plot the pressure, flow, velocity, and change of direction of the water through the entire range from entering the intake, up through the intake, and as it contacted the impeller. You'd even want several right behind the shoe, in a line across the opening. You'd want them in lines corresponding with the sides of the loader, in positions to compare the differencxe between the top of the intake and the bottom, the sides, and in the middle. You'd need to create "webs" of sensors thet bisected sections of the intake to plot the movement of the water as it traveled through those "webs" 1" from the wall, 2" from the wall, 3" from the wall and so on till you reached the center, all in a redial of say, 15 deg. or so. One sensor somewhere in the flow dosen't really tell you much of anything, does it? As soon as the water passes that sensor, it's changed it's flow characteristics. Am I being too analytical here?

[UBFJ #454]

One intake sensor along with a bowl sensor and possibly a nozzle sensor is enough or us to gain the information we need for our racing setups ... It perhaps is not enough for someone wanting detailed R&D data they feel required for specific design purposes ... But ... It works quite effectively for us as a bottom "Tuning" Aid ... Of course, it also helps a great deal if you have some experience "Tuning" Bottoms the Old Fashion Way ... By "The Seat of Your Pants" Trial & Error Method.