In the present Study, attention is focused oil the CFD simulation of trickle-bed reactors when the trickling-flow regime changes into the pulsing-flow regime, along with the parameters that characterize this latter regime. These parameters include the velocity at which the pulse front travels along the bed, the frequency of pulsations, and the Structure of pulses being formed (i.e.. the sizes of the liquid-rich and gas-rich zones). Results are presented for a three-phase reactor operating at an elevated pressure in the pulsing-flow regime. Several parameters that characterize the pulsing flow, namely, the velocity of Pulses traveling along the bed, the frequency Of pulsations and their Structure, the length of the pulses, and the length of the liquid-rich zone, were examined at high pressure by means of in Eulerian CFD model.