The paper reports on the results of numerical simulation of large-scale stationary vortices forming in hydrodynamical model of a vortex combustor. In particular, the effect of boundary conditions on the residence time and path length of the fluid particles has been explored. Validity of the numerical procedure has been verified by comparison of the simulation results with the experimental data obtained by measuring the velocity fields using a PIV method. On the basis of the data obtained, it is shown that the average residence time of the fluid particles in the vortex chamber in the case of formation of a single-helix and a double-helical vortex is substantially higher than the residence time of the particles in the flow regime with a rectilinear vortex. The average distance traveled by the particles also increases noticeably in case of the flow regime with the spiral structure's formation. Thus, based on the work results, it is possible to draw a conclusion about the increased effectiveness of the use of operating modes with the formation of spiral vortex structures.