This paper presents a numerical approach to develop an accurate Computational Fluid Dynamics (CFD) model for an electrostatic precipitator (ESP). The flow simulation was performed by using the CFD code FLUENT. Numerical calculations for the air flow are carried out by solving the Reynolds-averaged Navier-Stokes equations and turbulence is modelled using the realizable k-e turbulence model. Simulation with uniform (ideal) velocity profile is compared with that with measured (real) velocity profile at the inlet boundary. The model developed by using the measured velocity profile at its inlet boundary showed more reliable simulation results.