Diffusion flames are found in a variety of applications, such as in gas turbine combustors, afterburners, heat recovery steam generators, and industrial furnaces. The instability of diffusion flame is a common issue in these applications. In order to stabilize the flame, researchers usually utilized the bluff-body or swirling flow to generate a recirculation zone. The reverse flow of products with high temperature in the recirculation zone then would be used to ignite or sustain the flame. In the project, diffusion flame with different stabilization mechanisms will be studied with LES and steady diffusion flamelet model. Bluff-body stabilized flames are receiving significant attention in the turbulent combustion modelling field due to its applications in a wide range of combustion systems. The presence of complex recirculation zone in this type of flames provides a scope for improving the existing modelling techniques for accurately capturing turbulence–chemistry interaction. In addition, DES and hybrid RANS-LES model will also be tested and compared with LES results. Both LES, DES and hybrid RANS-LES need high resolution mesh and high performance computational resources. The simulation results will be used in the design process for the new burners with high performance in the modern Gas Turbine system.