Liñán's diffusion flame theory
Liñán diffusion flame theory is a theory developed by Amable Liñán in 1974 to explain the diffusion flame structure using activation energy asymptotics and Damköhler number asymptotics. Liñán used counterflowing jets of fuel and oxidizer to study the diffusion flame structure, analyzing for the entire range of Damköhler number.
Source: Wikipedia — Liñán's diffusion flame theory (CC BY-SA 4.0)