<font color='black' size='2' face='arial'>
<div><FONT face="Arial, Helvetica, sans-serif">Regarding the efficiency of Humphreys pump, there was considerable debate on this at the Royal institute in 1908.</FONT><br>
It would seem that the Rankin and Carnot cycle diagrams were equated with this four stroke engine., in order to establish the efficiency.</div>
<div>However, the "extended power stroke" continued on to a negative pressure before completion, resulting in the temperature of the exhaust gasses being only slightly above the ambient. this had never been observed in an ICE as the exhaust temperature formed a considerable portion of the wasted energy of the fuel being burned.</div>
<div>In other words the force of the fuel exploding was totally used in the Humphrey pump.</div>
<div> </div>
<div>GF.</div>
<div> </div>
<div> </div>
<div style="FONT-FAMILY: arial,helvetica; COLOR: black; FONT-SIZE: 10pt">-----Original Message-----<br>
From: Rolf Uhle <energiesnaturals@gmx.de><br>
To: Discussion of biomass pyrolysis and gasification <gasification@lists.bioenergylists.org><br>
Sent: Thu, May 26, 2011 12:43 pm<br>
Subject: Re: [Gasification] Fw: Underwater gasification?<br>
<br>
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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.
>
>
>
>
>
>
>
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