In numerical modelling, Large Eddy Simulations (LES) has evolved itself as a powerful tool for the prediction of turbulent premixed flames. In LES, sub-grid scale (SGS) modelling plays a pivotal role in accounting for various SGS effects. Chemical reaction rate in LES turbulent premixed flames is a SGS phenomenon and must be accounted accurately. Flame surface density (FSD) models based on laminar flamelet concepts are simple and efficient in accounting the chemical reaction rate, which is the main motive of this research.