door air inlet and outlet

Hi there,

I am developing a batch rocket stove and i need some advice for the air inlet - outlet.

My exhaust is Φ150mm and heat riser Φ100mm.
Is there any rule that apply between air inlet and outlet (exhaust) size dimensions in order to be effective? Do they have to be equal?

Regards

A general rule for batch box systems is to keep riser and exhaust sizes the same. A larger exhaust/chimney would probably not hurt, but there is probably no benefit to the larger size.

The door air inlet size is generally a fraction of the system (riser) size. Slots like your drawing shows would allow less airflow than a single equal-sized opening due to edge friction effects. https://Batchrocket.eu includes dimensions and ratios that may help you.