In this paper a numerical model of the full surge cycle is presented for the low-speed centrifugal blower and compared with the experiment. Surge phenomenon is very dangerous for the compressor operation. Therefore the possibility of studying its physics experimentally is strongly limited. The application of numerical methods allows one to safely analyze surge physics without causing risks to the operating crew. The paper presents a description of the applied numerical method and exhaustive analysis of the flow structures observed at consecutive stages of the surge cycle. The surge is known to be very difficult to be simulated due to large timescale and region of influence. The study also shows the importance of an appropriate choice of the simulation definition and the boundary conditions. The presented method allows gathering information about features such as the regions of flow reversal, pressure distributions, pressure rise, cycle frequency, and others. All the abovementioned information provides important input to the efficient anti-surge system design. The model has been validated by a comparison with experimental data. Thanks to simulation standardized anti-surge solutions could be possibly replaced with more efficient protection schemes tailored to a given machine.