Hi Mihai, I've attached an excel spreadsheet (you must enable macros for the pipe friction visual basic calculations to run) with an example calculation of what you ask for. You said a 2" pipe and 1/2" nozzle, but didn't specify pipe length or head, so I assumed 30 feet of static head and 200 feet of pipe (using smooth plastic for the roughness value) and two 90 degree elbows and an entrance loss.
This shows that a 1/2 inch nozzle allows a flow 26 gallons per minute (about 2 liters/second) from a net effective head (after pipe friction losses) of 27 feet. The shaft power from an 85% efficient turbine ould be 111 Watts, and assuming an 80% efficient generator you'd have 89 W of electric power. Obviously if you want 2-4kW you'll need more head and a larger pipe than I've assumed here. The spreadsheet can also be downloaded from http://h-hydro.com/pipedp.xls but I don't recall what site values were entered when that copy was uploaded. Joe http://h-hydro.com --- In [email protected], "Mihai Radulescu" <[EMAIL PROTECTED]> wrote: > I want to build a microhydropower system in the mountains, the aim > would be to generate 4kW, but alos 2kW is acceptable. > > I have read and undertood the theories abot head and flow, but I don't > know how to calculate the effective water flow taht would pass through > the penstock/nozzle/turbine; the idea is that the waterflow of the > creek is big enough, and I want to install just a sort of collection > system that would pour water into the penstock, as much as the > penstock/nozzle would run. > How do I calculate, at least approximatively, the waterflow through a > vertical plastic pipe of, let's say, 2" diameter and a head of X > meters. > And more, if the pipi would finish with a 1/2" nozzle, how this would > affect the waterflow ? > > Regards, > > Mihai ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/FGYolB/TM --------------------------------------------------------------------~-> Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. More information on micro hydropower at http://microhydropower.net To unsubscribe: send empty message to [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/microhydro/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
