[Vwdiesel] P1 V1...

Mark Shepherd mark at shepher.fsnet.co.uk
Sun Jul 18 19:41:19 EDT 2004

Sorry I obviously wasnt very clear... my centrifugal pump was the uplift pump. Shearing of the diesel would generate the heat; and the hammering which would increase with uprated injector pressures to contend with.
It reminds me of the time when I was invited into a research program that used a windmill connected mecanically to a gearbox/hydraulic brake that had the pure aim to convert all mechanical energy to heat. This would then be pumped round a heating circuit to provide heating for commercial greenhouses... Needless to say I tuned the post down as I had set my heart on a career change [accounting and law]... yuk; office work not for me...
Loren wrote...
 I've been thinking on this what with growing up with many hydraulics on 
tractors, pruning equipment and such plus plans for various hydraulic 
powered devices as well as your basic understanding of conservation of 
  First off, heat MUST be released unless motion is created and still 
then there will be heat released if only due to friction and momentum.
  The "stored" energy IS in pressure, releasing the pressure releases 
the energy.
  It's not like with air where simply "dumping" the pressure creates heat 
since it's not compressed like air.  It's the "squish" or squirt factor 
that makes the heat.  Just think of it as frictional loss from the fluid 
squirting through an opening.  The greater the pressure drop, the less 
restricted the flow thus the more heat.
  It makes sense to me that the majority of the heat comes from the 
bypass and so far unmentioned, the main "lift" pump.
  There's sort of a mental picture misrepresentation of the governor 
weights.  You say "sloshing" and that implies air and fluid.  There is 
no air so you don't have the changing density and speed of fluid motion.
  I'd suspect more heat created in a gas/fluid slosh than straight fluid.
We have sprayers with mixing paddles there are outboard boats run in 
test tanks and those are DESIGNED to move fluid.  They don't create 
any noticeable heat.  Just a ball shape or whatever dragging through 
a liquid would seem at first to make a lot of drag and heat.  BUT, If there's 

clearance for fluid flow around the weights then I contend there would be 
less heat generated than in tight quarters. 
  Because the tighter it gets, the more of a pump-like setup you have.  It 
makes pressure differential.  With no pressure differential then all you 
have is drag thus friction.
  Take a syringe, load it with water and pinch it off (needle off) with the 
of your finger and give it a hard squirt.  With the right combination you 
should feel some quick heat.  It REALLY works with a small air pump.
  Just look at a carburetor, where you're forcing a liquid into a lower 
pressure.  You create a vacuum in a venturi so that the gas boils at a 
lower temperature and vaporizes.  You'd first reason that things would 
get warm from the boiling gas but it's quite the opposite.  Things get 
cold, real cold.  Of course this is due to a change in the state of the 
matter rather than the pressure drop being the relevant operation.

Mark (The Miser)Uk 
"There's nothing more stimulating than driving past a bonfire and then realising it's your car that's smokin"


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