Investigation on the Unsteady Aerodynamics of an Industiral Fan

B3 - Unsteady Aerodynamics and Flow Simulations

There are controversial requirements involved in developing numerical methodologies in order to compute the flow in industrial fans. The full resolution of turbulence spectrum in such high Reynolds number flow configurations entails unreasonably expensive computational costs. The authors applied the study to a large unidirectional axial flow fan unit for tunnel ventilation to operate in the forward direction under ambient conditions. This delivered cooling air to the tunnel under routine operation, or hot gases at 400°C under emergency conditions in the event of a tunnel fire. The simulations were carried out using the open source code OpenFOAM, within which they implemented a (very) large eddy simulation (VLES) based on one-equation SGS model to solve a transport equation for the modelled (sub-grid) turbulent kinetic energy. This sub-grid turbulence model improvement is a remedial strategy in VLES of high-Reynolds number industrial flows which are able to tackle the turbulence spectrum's well-known insufficient resolution. The VLES of the industrial fan permits to detect the unsteady topology of the rotor flow. This paper explores the main secondary flow phenomena's evolution and speculates on its influence on the actual load capability when operating at peak-pressure condition.