Well, the rough approximation of a pint's a pound (the world 'round) seemed
good enough for the precision required, and I DID assume a reduced head of
2 ft at 1250 rpm. This has to be about the minimum head, because of the
height of the radiator.
In fact, the head has to be roughly 2 ft at minimum rpm (500), so if it's
proportional to the square of the speed, it already has to be 12.5 ft by
1250 rpm, and 200 ft (over 80 psi) at 5000 rpm ! Somehow, I don't think
the relation holds over this range <g>
Several people have corrected my misunderstanding about the origins of this
engine.
Thanks to all of you. However, does anyone know how much power it made in
"Standard Vanguard" trim (ie as originally designed) ?
Randall
On Thursday, March 18, 1999 1:43 PM, Michael Marr [SMTP:mmarr@idcnet.com]
wrote:
> Actually, the fuel flow rate was .5 PINTS/BHP/Hr, not lbs/BHP/Hr. Thus,
> under the conditions you have stated and using my initial assumptions,
the
> heat equivalent of 24 BHP would be about 61,100 BTUH. This would require
a
> cooling water mass flow rate of 51 lbs/min, or a volume flow rate of 6.1
> gpm. HP consumed by the pump would be .027 BHP. At twice the speed, the
> BHP would be .22 BHP and the flow rate would be 12.2 gpm, with a heat
> rejection capacity of 122,000 BTUH, and at four times the speed the BHP
> would be 1.75 BHP, flow rate 24.4 gpm and heat rejection capacity of
244,000
> BTUH. HOWEVER, all this assumes that the TDH, which is determined by the
> pressure drop across the system, stays constant, which it doesn't. In
fact,
> the pressure drop is dependent upon flow rate through the system and
varies
> as the square of the flow rate. So, as the speed doubles, power increase
> eight times and pressure drop increases four times. This is why variable
> speed pumping is used in large variable flow pumping applications in
> industry - a 4,000 HP pump running at half capacity will only require 500
HP
> if run at variable speed, whereas it will consume almost the full 4000 HP
if
> the flow rate is changed by throttling the flow with a valve. See, you
> didn't know we had such a high-tech, energy efficient device on our cars,
> did you?
>
> BTW, the TR engine was originally a saloon car engine that just happened
to
> be applied to a Fergusson tractor back in the late forties - it was never
> developed from the tractor engine.
>
>
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