Also known as dimensional analysis, the basis of dimensional analysis is the principle of dimensional consistency and π theorem. The principle of dimensional consistency shows that all physical equations derived from basic physical laws must have the same dimension. According to the π theorem proposed by Buckingham, any physical equation with the same dimension can be expressed as a set of zero functions with dimension 1, that is, F(π 1, π2, π3, ..., πi)=0.

It is a method to analyze the dimensions of physical quantities related to a process and obtain several dimensionless numbers (dimensionless parameters) between groups. It is a chemical engineering research method that guides experiments together with similar theoretical methods, and is widely used in the research of engineering disciplines.