To better understand the rocket stove I decided to break each section down into individual components.
Here is a crude picture I made to help illustrate.
Section 1. is where to add the fuel source, in this case, wood. The dimensions will depend on how much wood you want burning at once. The idea is to use smaller sticks or wood cut into smaller pieces which maximize the surface area of the fire. The wood is placed vertically and only the ends are burning. As the fuel burns it self feeds with assistance of gravity.
Section 2. is where the remaining fuel in the form of smoke is mixed with air. If we use a slightly smaller opening then according to the Bernoulli Principle, as the pressure decreases(smaller opening), the speed of the fluid, in our case air, increases. Thus increasing "rocketiness". The greater the temperature is in this section the greater the rocket effect. This is due to the difference of the external and internal temperatures as proven in the flow equation.
Section 3. is the Heat Riser where the heat expansion of air is capitalized. This is the work-horse of the stove. Utilizing the Stack Effect or Chimney effect where the larger the size of this section, the stronger the effect of fast air movement. This variable strongly effects the rocket effect.
Section 4. not shown is where a barrel such as a 55 gallon steel drum acquired from a metal recycling yard for dirt cheap is added over the top of the heat riser to capture and radiate heat into the room also cooling the air which adds more momentum to the movement of the air.
Section 5. would be the heat bench where a section of pipe is laid horizontally to extract heat and store it like a capacitor stores electricity for release into the room over an extended period of time long after the fire is extinguished.
Section 6. would be where the exhaust exits the building. This section of pipe is independent of the diameter of the other components within the system. The diameter of the exhaust will not have an effect on the intake because of compressibility of air. If you have a 4" exhaust versus an 8" exhaust, the main variable effected is the air pressure exerted outwardly on the pipe at that point in the flow. If it is too small, the pressure will eventually exceed the design limits of the pipe and burst.
Most of my research was conducted using wikipedia and a paper titled "A Tutorial on Pipe Flow Equations" by Donald W. Schroeder, Jr. Utilizing the equations and then testing them with various configurations confirmed what I have explained.
