Effect of inlet nose insertion on the performance of a flanged conical diffuser

This study presents a three-dimensional computational fluid dynamics (CFD) investigation of a flanged conical diffuser, focusing on the aerodynamic benefits of integrating an inlet nose geometry. Simulations were conducted in Ansys 2019 R3 using the SST k–ω turbulence model with non-linear eddy viscosity corrections to capture flow separation and reattachment. Validation against experimental data showed excellent agreement for the baseline case. The nosed configuration yielded marked improvements: higher peak velocity ratios, increased maximum pressure coefficients, and enhanced overall pressure recovery. Flow-field analysis revealed that the inlet nose effectively mitigates adverse pressure gradients, delays boundary layer separation, and weakens recirculation zones. Turbulence kinetic energy was significantly reduced near walls and in the core region, indicating lower energy dissipation. Overall, the results demonstrate that the nose geometry functions as an efficient passive flow control device, offering substantial aerodynamic gains for diffuser-augmented wind turbines and other renewable energy systems.