本项目针对湍流火焰逆梯度输运特性建模发展的不足，从多重梯度耦合作用下的同轴射流火焰入手，开展逆梯度输运现象的理论分析和试验研究，采用多参数同步测量的激光诱导磷光成像分析方法，拟解决关键科学问题：多重梯度耦合对同轴射流火焰逆梯度输运的作用机制。①采用激光诱导磷光成像分析方法，诊断点火、局部熄火与再燃等参数突变或间歇性现象，明确湍流火焰的物理尺度和特征；②探索逆梯度输运的生成机制、判别准则和转化过程，认知多重梯度耦合作用下的湍流输运和火焰传播过程；③建立体现逆梯度输运的数学描述和物理模型，并进行适用性验证和数值分析，为探索湍流燃烧机理提供技术支撑。通过本项目研究，在湍流火焰物理模型和激光测量技术方面取得突破性的进展，对于现有物理模型在问题描述上的完善具有非常重要的学术价值，相关成果有利于推动发动机燃烧及其控制、节能减排、废热利用和火灾等多物理场耦合领域的技术进步以及交叉学科的发展。

This project conducts theoretical and experimental investigation on the phenomena of counter gradient transport (CGT) in coaxial jet flame driven by multiple gradient coupling, in view of the insufficient development of CGT modeling. The key scientific issue to be resolved is to understand the mechanisms of multiple gradient coupling on CGT in coaxial jet flame, based on the synchronized measurements by laser induced phosphorescent imaging (PhI) technique. Firstly, the abrupt parameters or intermittency phenomena in ignition, local extinction, and reignition processes will be diagnosed by PhI technique to clarify the physical scales and features of turbulent flame. Secondly, the CGT formulation, transformation and discrimination will be explored to recognize the turbulent transport and flame propagation in coaxial jet flame driven by multiple gradient coupling. Finally, the mathematical description and physical model will be established to support the investigation on turbulent combustion by CGT characterization after numerical validation. Through the implementation of this project, the expected breakthrough progresses in turbulent flame model and laser measurement technique are of great academic importance in the improvement of modeling on counter gradient transport in coaxial jet flame. The achievements are also beneficial to promote the progresses in multiphysics coupling, such as engine combustion and its control, energy conservation, emission reduction, exhaust heat utilization and conflagration, and the development of interdiscripline.