A comparison study is undertaken to investigate the suitability of three widely used models for soot formation in a turbulent flame. Predictions of the models in a turbulent spray flame, which provides high soot concentration, are compared with each other and with experimental measurements. The soot formation models sought to be studied here include two single-step models and a two-step model. The single-step soot models calculate soot formation directly while the two-step model computes soot through the formation of nuclei radicals. In order to model the reactive flowfield inside the combustor, a hybrid Eulerian-Lagrangian method is employed. Equations governing the gas phase are solved by a control-volume based semi-implicit iterative procedure while the time-dependent differential equations for fuel droplets are integrated by a semi-analytic method. To increase the accuracy of the two-step model, it is modified by increasing the role of fuel concentration on the process of soot formation. Comparison of the results of different models reveals that the modified model makes the best agreement with the experimental data. In addition, under different equivalence ratios, the behavior of the modified model is the most accurate one. Hence, it is considered as a suitable candidate for soot formation prediction

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