Hi, I've tried using a boat propeller on one of our axial turbines (15kW, 3m gross head) and it worked. What I did is: first I computed for the ideal blade profile based on flow rate, gross head, and RPM requirements. Then, I looked for a propeller that closely matched my computations. By buying an off-the-shelf component, I ensure that replacement parts for the turbine will be available without special fabrication, although you have to sacrifice a bit of efficiency due to the inappropriate shape of the blade tip. The difficult part is in looking for a propeller that closely matches what you need. The blade has only a limited range of tip-speed ratio wherein it will operate at high efficiency. Increasing the tip speed will increase the RPM and reduce the pitch for a given head and flow rate. Increase in head will increase the RPM and flow rate if the turbine size remains constant. Flow rate is proportional to the axial turbine's cross-section and is related to the square-root of the gross head. Use of flat plates will reduce your efficiency but if the flow rate is more than sufficient, I think it is worth it for a bit of sacrifice in efficiency in excange for simplicity of design, fabrication and maintenance. Axial pumps are not so available in the Philippines but there is a wide variety of propeller sizes, shapes and configurations.
chilechinadollz <[EMAIL PROTECTED]> wrote: Hello All, I am a new member, but I have enjoyed reading your group for a while now. I have a question. Has anyone explored the use of boat propellers as runners in a propeller turbine? I have read about supposedly successful turbines in third world apps where the runner was made up of flat steel blades. It seems like the blade profile of boat propellers would be more efficient. They are certainly easy obtain. Secondly, if there is experience out there, how would one relate prop pitch to the conditions; ie. head and flow? Thanks, Martin 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] SPONSORED LINKS Energy management Energy gels Energy conservation home Energy savings Energy Energy efficiency --------------------------------- YAHOO! GROUPS LINKS Visit your group "microhydro" on the web. To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. --------------------------------- --------------------------------- Click here to donate to the Hurricane Katrina relief effort. [Non-text portions of this message have been removed] ------------------------ 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/
