From: henry@spsystems.net   
      
   In article <41DDFA0B.9D6CCC17@nospam.com>,   
   Andrew Nowicki   wrote:   
   >...This kind   
   >of cooling has obvious flaw: hydrocarbons are volatile,   
   >so large volume of hydrocarbons is needed.   
      
   Since the hydrocarbons are being used as fuel anyway, they aren't wasted.   
   Moreover, don't be misled by the terminology:  the curtain is *vapor*, not   
   liquid.  Cooling with a liquid film is called film cooling.   
      
   >Molten salts are much better. A molten mixture of 60   
   >percent sodium nitrate and 40 percent potassium nitrate   
   >is used in solar thermal power plants. Red hot fluoride   
   >salts (sodium fluoride and zirconium fluoride) were used   
   >as coolants in a nuclear reactor.   
      
   If memory serves, both are quite corrosive at high temperatures.  They   
   are also relatively dense, so a supply of them will be heavy, and of   
   course they're no use as fuel.  (Actually, the nitrates are oxidizers,   
   although not tremendously good ones.)   
   --   
   "Think outside the box -- the box isn't our friend."    |   Henry Spencer   
                                   -- George Herbert       | henry@spsystems.net   
      
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    * Origin: you cannot sedate... all the things you hate (1:229/2)