ps I think the beauty of the a Humphrey-inspired water jet is that it would have relatively no moving parts so it's weight to power ratio of efficiency is better than that of other engines overcoming the friction losses of a conventional water jet engine (as per water ski) H. ----- Original Message ----- From: Henri Naths To: Discussion of biomass pyrolysis and gasification Sent: Thursday, May 26, 2011 8:57 AM Subject: Re: [Gasification] Underwater gasification?
Hi Daniel,and list < I don't think it would be an efficient means of low speed marine propulsion though; it would suffer from low propulsive efficiency because the jet velocity would be too high.> Have you considered the propulsion end of a jet ski or a Jet Boat in your analysis . True the efficiency is slightly lower than a straight prop boat but it is expelling a relatively small stream of water at a high velocity. I hear what you are saying about the jet engines but as I previously pointed out in a post , water has 700 times the density than that of air so you have to factor that in the formula. Thanks Henri ----- Original Message ----- From: Daniel Chisholm To: Discussion of biomass pyrolysis and gasification Sent: Sunday, May 22, 2011 5:51 PM Subject: Re: [Gasification] Underwater gasification? A Humphrey-inspired water jet is an interesting idea. FWIW I don't think it would be an efficient means of low speed marine propulsion though; it would suffer from low propulsive efficiency because the jet velocity would be too high. The efficiency of a reaction engine (which is something that generates thrust by accelerating and expelling mass - a very broad category that includes not just jet and rocket engines but also propellers on aircraft and ships) depends on the speed at which the mass is expelled. Accelerating a small mass to a large speed, is not as efficient as accelerating a larger mass to a lesser speed. If you look at aircraft jet engines today (high bypass ratio turbofans) you will notice that they are much larger in diameter than the jet engines of the 1950s (turbojets) - this is why. -- - Daniel Fredericton, NB Canada ------------------------------------------------------------------------------ _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/ __________ Information from ESET NOD32 Antivirus, version of virus signature database 6155 (20110526) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __________ Information from ESET NOD32 Antivirus, version of virus signature database 6155 (20110526) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com
_______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/
