Somewhat urgent question¿ Interior ross sectional area of a plancha stove.

[Charlie Sellers]

I can get to town/electricity every few days and am on line on and off for a few hours right now.  The dimensions of our planch stove design here in Peru are somewhat limited by the dimensions of the types of hollow brick available (I can only cut tile - or break bricks in a clumsy fashion - and have only simple tools) so various dimensions of the stoves are limited.  Particularly the chimneys - only scrap iron pipe or stacked hollow bricks are here - so I want to be a little flexible in the open area of the stove at various places in the cross section.

One ¨rule¨of the rocket is constant cross sectional area throughout the stove but it seems that the exit/chimney really only needs a larger area than the rocket entrance - true?  I use the analogy of a river flowing into a new channel - if the area diminishes then smoke backs up into the room.  And if the new channel is smaller then the flow out needs everything is fine.  And if there is a temporary wide spot inside the stove then there is no problem, as long as the exit is larger than the entrance?
   
  I am trying to increase the size of the combustion chamber as much as I can, since the plancha will slow the time to boil (and other perceived problems), to increase the firepower a little.  But I only have limited size possibilities for either the entrance and exit, and I don´t yet know how to exactly take into account that there is an expansion of gas as it heats, and there is a net increase in gas volume during combustion.  How does the equal area rule take such things into account¿  I am taking some risks, but as long as I increse the chimney area I hope to be fine.  As always, I want the best conditions to increase the burning of the smoke before it leaves.
   
  Any advice on whether commercial floor tiles can generally be the walls of the combustion chamber¿  What exactly is baldosa tile¨¨ - specifications¿  I tested mine (and also the hollow bricks) in a very hot fire with no problems, but success in the longer run is too important to take too many risks.
   
  thanks in advance!
   
  Charlie
   


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