The vibrations and noise caused by pressure pulsations are one of the major problems in volumetric compressors manifolds. There is still no easy solution for this problem. Passive damping of those pulsations is possible using specially shaped nozzle placed in place of the straight tube. Experimental analysis of the pressure pulsations damping caused by a nozzle is possible however only some arbitrary chosen nozzle shapes can be investigated. The analysis of damping of the impulse flow by the nozzle using CFD simulation is more general and gives the possibility to estimate the nozzle influence on the pulsating flow in theoretical way, so many different shapes can be investigated. In this paper examples of impulse flow damping factors for three different nozzles have been shown.