Posted by z on October 17, 2008, 9:26 pm
>
>> Doing a little tuning now that winter is here.
>>
>> Starting with the connections I used a larger T on the 1-1/2 inch
>> line and then stepped down to the 3/4ths at the last possible section
>> before the nozzles. Also took apart all the connections and
>> dremmeled out the steps to help a smooth transition between sizes,
>> rather than having hard edges going from like 1-1/2 inch to 1 inch
>> and then to 3/4 ths -- kind of like you would to port and polish an
>> intake manifold for an engine.
>>
>> I'm still trying to get a large Wye rather than a T. I have access
>> to a fire hose Wye but making the quarter turn connection (wildland
>> firefighting) to NTP is somewhat difficult. Also saving up my
>> pennies to move to two inch rather than inch and a half, which should
>> nearly double my output according to the math. Its not cheap
>> though.. so I might hold off on the wye biz till I upgrade the main
>> pipe.
>>
>> Also moved the nozzles as close as I could get to the pelton wheel
>> without hitting it.. I'm getting around 40 volts open running where
>> as before I'd get maybe 30-32. Now i just need to redesign the
>> brakets to keep it aimed better, but i'm getting ready for some
>> serious rain.
>>
>> Still can only run it about 10 hours a day now.. come the RAIN!
>>
>
> If you already have the 1 1/2" pentstock, you could add another for
> less losses, rather than replacing the whole thing. This could
> eliminate the Wye, also.
thats an idea i'd never even considered. one line for each jet.. woah
My setup now is a 2 inch 100 foot line that goes into 300 more feet of 1-
1/2, so I had always thought to just make the rest 2 inch. But I could
add another one altogether.. and under low water just use the one.
nice!
>
> For the Wye, they might make such a part for built-in vacuum systems.
>
> PVC pipe can be bent when it is heated, and perhaps even stretched to
> smaller diameters for nozzles.
yeah i might try that eventually
thanks man!
-zachary
>
>
>
Posted by BobG on October 17, 2008, 10:18 pm
> My setup now is a 2 inch 100 foot line that goes into 300 more feet of 1-
> 1/2, so I had always thought to just make the rest 2 inch. But I could
> add another one altogether.. and under low water just use the one.
==========================
=====================
So the electrical analogy is: consider the 2" pipe as 100' of #12 wire
and the 1 1/2" pipe as 300' of #14 or whatever gauge has the same
ratio of cross sectional area. If I know the ohms per foot, I can calc
the total IR drop. Is this about the same as the pressure loss along
the 400' of pipe? Seems the water has to run thru the 1 1/2" pipe
faster, so it must have more frictional loss. What's the units of
water flow resistance?
Posted by Ken Maltby on October 18, 2008, 1:43 am
> My setup now is a 2 inch 100 foot line that goes into 300 more feet of 1-
> 1/2, so I had always thought to just make the rest 2 inch. But I could
> add another one altogether.. and under low water just use the one.
==============================================
So the electrical analogy is: consider the 2" pipe as 100' of #12 wire
and the 1 1/2" pipe as 300' of #14 or whatever gauge has the same
ratio of cross sectional area. If I know the ohms per foot, I can calc
the total IR drop. Is this about the same as the pressure loss along
the 400' of pipe? Seems the water has to run thru the 1 1/2" pipe
faster, so it must have more frictional loss. What's the units of
water flow resistance?
You could be lazy like me, and use the tables in the
"Pocket Ref" by Thomas J. Glover Sequoia Publishing
ISBN 1-885071-00-0
It has a lot of other such data for water;
including:
Friction loss in pipe fittings
Horizontal pipe discharge ( easy way to get the GPM)
Nozzle Discharge ( GPM for a given nozzle dia. @ a given
pressure)
and at least a half dozen more.
Sequoia Publishing, Inc.
P.O. Box 620820 Dept. 101
Littleton, Colorado 80162-0820
(303) 972-4167
http://www.bookfinder.com/dir/i/Pocket_Ref/1885071000/
Luck;
Ken
Posted by z on October 18, 2008, 2:36 am
>
>> My setup now is a 2 inch 100 foot line that goes into 300 more feet
>> of 1- 1/2, so I had always thought to just make the rest 2 inch. But
>> I could add another one altogether.. and under low water just use the
>> one.
> ==============================================
> So the electrical analogy is: consider the 2" pipe as 100' of #12 wire
> and the 1 1/2" pipe as 300' of #14 or whatever gauge has the same
> ratio of cross sectional area. If I know the ohms per foot, I can calc
> the total IR drop. Is this about the same as the pressure loss along
> the 400' of pipe? Seems the water has to run thru the 1 1/2" pipe
> faster, so it must have more frictional loss. What's the units of
> water flow resistance?
>
> You could be lazy like me, and use the tables in the
> "Pocket Ref" by Thomas J. Glover Sequoia Publishing
> ISBN 1-885071-00-0
>
> It has a lot of other such data for water;
> including:
> Friction loss in pipe fittings
>
> Horizontal pipe discharge ( easy way to get the GPM)
>
> Nozzle Discharge ( GPM for a given nozzle dia. @ a given
> pressure)
>
> and at least a half dozen more.
>
> Sequoia Publishing, Inc.
> P.O. Box 620820 Dept. 101
> Littleton, Colorado 80162-0820
> (303) 972-4167
>
> http://www.bookfinder.com/dir/i/Pocket_Ref/1885071000/
>
I use this application to do the calculations. You can try different
sized pipe and pressures to see what to expect
http://www.energyalternatives.ca/Downloads/MicroHydroCalc.exe
Posted by daestrom on October 18, 2008, 3:00 pm
BobG wrote:
>> My setup now is a 2 inch 100 foot line that goes into 300 more feet
>> of 1- 1/2, so I had always thought to just make the rest 2 inch. But
>> I could add another one altogether.. and under low water just use
>> the one.
> ==============================================
> So the electrical analogy is: consider the 2" pipe as 100' of #12 wire
> and the 1 1/2" pipe as 300' of #14 or whatever gauge has the same
> ratio of cross sectional area. If I know the ohms per foot, I can calc
> the total IR drop. Is this about the same as the pressure loss along
> the 400' of pipe? Seems the water has to run thru the 1 1/2" pipe
> faster, so it must have more frictional loss. What's the units of
> water flow resistance?
Trouble with water flow is that the pressure drop usually follows flow
squared. That is, double the flow and you have four times the pressure
drop. Not the simple linear relationship of Ohm's law.
This means that for a given flow rate, the pressure drop is proportional to
1 / d^5. So if you double the pipe diameter, you get 1/32 the pressure drop
if you somehow manage to keep the same flow. So there's definitely
something to be said for going with larger pipe.
daestrom
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>> Doing a little tuning now that winter is here.
>>
>> Starting with the connections I used a larger T on the 1-1/2 inch
>> line and then stepped down to the 3/4ths at the last possible section
>> before the nozzles. Also took apart all the connections and
>> dremmeled out the steps to help a smooth transition between sizes,
>> rather than having hard edges going from like 1-1/2 inch to 1 inch
>> and then to 3/4 ths -- kind of like you would to port and polish an
>> intake manifold for an engine.
>>
>> I'm still trying to get a large Wye rather than a T. I have access
>> to a fire hose Wye but making the quarter turn connection (wildland
>> firefighting) to NTP is somewhat difficult. Also saving up my
>> pennies to move to two inch rather than inch and a half, which should
>> nearly double my output according to the math. Its not cheap
>> though.. so I might hold off on the wye biz till I upgrade the main
>> pipe.
>>
>> Also moved the nozzles as close as I could get to the pelton wheel
>> without hitting it.. I'm getting around 40 volts open running where
>> as before I'd get maybe 30-32. Now i just need to redesign the
>> brakets to keep it aimed better, but i'm getting ready for some
>> serious rain.
>>
>> Still can only run it about 10 hours a day now.. come the RAIN!
>>
>
> If you already have the 1 1/2" pentstock, you could add another for
> less losses, rather than replacing the whole thing. This could
> eliminate the Wye, also.