[ExI] Electric cars without batteries

[spike]

> ...On Behalf Of BillK
> Subject: Re: [ExI] Electric cars without batteries
> 
> On Mon, Oct 25, 2010 at 4:16 AM, spike  wrote:
> <snip>
> > ...If 
> > instead of a condenser, we throw the low pressure steam overboard 
> > after it passes the turbine, the idea would require too 
> much water mass for a typical trip.
> >
> > ...
> <http://www.steamcar.co.uk/design.html>
> 
> Length  	7.663 m  	
> Width 	1.700 m 	
> Tall 	        1.700 m 	
> Weight 	3 tonnes 	
> Engine 	Two stage turbine      13,000rpm max turbine revs
> Transmission 	Rear wheel drive 	
> Power 	268 kw 	360 hp
> Top speed 	274 kph 	170 mph
> 
> New world record!
>
> BillK

Hey BillK, I did some fooling around with BOTECs using the numbers they give
on your steamy racecar site.  Here's something I found amusing.  

Assume the steam exhaust pipe is horizontal and pointing aft (logical
assumptions.)  What is the diameter of the pipe required such that the
velocity of the exhaust equals the top speed of the car, so that the exhaust
is stationary with respect to the ground upon exit?

My BOTECs:  top speed 274 kph, that's about 76 m/sec, 1000 litres of water
in 25 minutes is about 670 g/sec and a mole of steam at 100 C exhaust
temperature (can't be cooler than 100 C, otherwise it wrecks the turbine
quickly) is about .6 g/liter, so for the exhaust velocity to be 76 m/sec the
exhaust area is about 150 cm^2, or diameter about 13 cm.  Interesting
result, because that is a size easily visualized: typically drainage pipe is
almost that diameter, and 5.5 inches is the average length of man's best
friend.

That would be one impressive plume of sparkly white steam billowing out the
back, ja?  I wonder if there is a YouTube somewhere?

{8-]

spike