Numerical simulation of local loss coefficients of ventilation duct fittings

The knowledge of the local loss coefficients is important for the accurate calculation of ventilation duct pressure loss. In practice, the pressure loss of ventilation duct is very often forecasted, what causes the wrong design of the ventilating fan. A large number of local loss coefficients exist, but the published data are different. The local loss coefficient can be estimated experimentally by the measurement on the real model, or with using of numerical simulation. The paper presents the using of CFD simulation for local loss coefficients of ventilation duct fittings (especially elbows and bends). The simulation results were compared with published data.