The Combustion Analogue
                
         Each O is a heating-coil/ thermocouple pair
      --------------------------------------------------
 air- O    O    O    O    O    O    O    O    O    O
    -->                                             --->
 fuel O    O    O    O    O    O    O    O    O    O  outlet
    -->                                             --->
 entryO    O    O    O    O    O    O    O    O    O
      --------                                        --
      ///////!  O    O    O    O    O    O    O    O  !/
      ///////!      recirculation zone, where         !/
      ///////!  O    O    O    O    O    O    O    O  !/
      ///////!      elevated temperatures could       !/
      ///////!  O    O    O    O    O    O    O    O  !/
      ///////!      prevail                           !/
      ///////!  O    O    O    O    O    O    O    O  !/
      ///////!                                        !/
      ///////!  O    O    O    O    O    O    O    O  !/
      --------------------------------------------------


                               ---------------
      heat  ^                  !             !
      input !                  !             !
      rate  !                  !             !
            !                  !             !
            !                  !             !
            !                  !             !
            !__________________!_____________!
                   --- reactedness ----->