An experiment-based closure framework for turbulent combustion modeling is further validated using the Sydney piloted turbulent partially premixed flames with inhomogeneous inlets. The flames are characterized by the presence of mixed mode combustion. The framework’s closure is “trained” on multi-scalar measurements to construct thermo-chemical scalar statistics parameterized in terms of principal components (PCs). Three flame conditions are used for this training, while an additional flame is used for validation. The results show that the leading PCs exhibit complex features near the jet inlet where effects of partial premixing and the presence of different burning modes are strong. These features may not be captured through a strict definition for the mixture fraction or measures of reaction progress. Further downstream, the first 2 PCs tend to be reasonably correlated with parameters that are characteristic of nonpremixed flames, including the mixture fraction and the progress variable. Comparisons of the model predictions for unconditional mean and RMS for the measured quantities show a very good qualitative and quantitative agreement with experimental statistics for all 4 flames using the same closure for the PCs governing equations.

使用具有不均匀入口的悉尼先导湍流部分预混火焰进一步验证了用于湍流燃烧建模的基于实验的闭合框架。火焰的特点是存在混合模式燃烧。该框架的闭包经过多标量测量“训练”，以构建根据主成分 (PC) 参数化的热化学标量统计。本次培训使用了三种火焰条件，而另一种火焰用于验证。结果表明，主要的 PC 在射流入口附近表现出复杂的特征，其中部分预混的影响和不同燃烧模式的存在很强。这些特征可能无法通过混合物分数的严格定义或反应进程的度量来捕获。再往下游，前 2 个 PC 往往与非预混火焰的特征参数合理相关，包括混合分数和进程变量。对测量量的无条件均值和 RMS 的模型预测的比较表明，对于所有 4 种火焰，使用相同的封闭控制方程的 PC 与实验统计数据具有非常好的定性和定量一致性。