But it must have a big volume of pressureproof vessel inside the hull. And if I calculate it right, the Humphrey pump delivers some 260 net kW. No idea how high it's efficiency is, shure not 100 %! Neither how efficient a jet propulsion like this could be. But even 260 kW are not much for a big ship with a huge vessel inside. ICE's compress the air much more and have a higher energy density. Sometimes beauty and virtue don't go the same way !
Rolf Am Donnerstag, 26. Mai 2011 17:13:30 schrieb Henri Naths: > 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. > > > > > > > > --------------------------------------------------------------------------- > --- > > > _______________________________________________ > 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.bioene > rgylists.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/
