The design of ventilation systems, with increasing complexity, is based on simulation methodologies involving CFD and CAA methods. Design strategies based on simulations including a complete geometrical description of each component are computationally expensive. Affordable design tool-chains need to replace single system components, such as rotors, with simplified computational approaches. In this contribution, the benefit of modelling fan blades by means of line-distributed sources is investigated, based on a previous work in which a fast and physical-principles based rotor noise model was presented. A simplified analysis on the effect of non-uniform inflow and out-flow conditions on an axial fan will be presented.