What type of pressure does draft in a combustion system depend upon?

Draft in a combustion system is fundamentally influenced by the pressure difference between two points, which is crucial for maintaining airflow and effective combustion. This pressure difference allows for the movement of air into the combustion zone and the expulsion of combustion gases.

The working principle behind draft relies on the fact that air naturally flows from an area of higher pressure to an area of lower pressure. In a combustion system, factors such as stack height, temperature of the flue gases, and external atmospheric conditions can create variations in pressure, resulting in the necessary draft for efficient combustion.

Static pressure and dynamic pressure both play roles in fluid dynamics but do not directly account for the mechanism in which draft operates. While static pressure refers to the pressure exerted by a fluid at rest, and dynamic pressure is related to the fluid's motion, neither captures the essential idea of creating a pressure variance that promotes airflow.

Thus, the most accurate and complete understanding of draft relies on recognizing it as a result of the pressure difference between two specific points in the system, ensuring that there is an adequate supply of oxygen for combustion and an effective removal of exhaust gases.