MODELING OF A DECELERATION OF THE AXIAL FLOW BY VORTEX WAKES ON THE NEJ BLADE
The results of analytical modeling of the system of tip helical vortices behind the rotating blades of the NEJ rotor are presented (the NEJ was proposed by N.E. Joukowsky). For the first time, the influence of the distribution of vorticity in the core for each tip vortex of the wake on the total deceleration of the velocity in the rotor-plane was taken into account. This result was obtained by extending the Dyson method for determining the induced velocity around a single helical vortex with a constant distribution of vorticity in the core to the many blade vortices in the wake. The greatest effect from the refined description of the vortex system was obtained with an increase in tip speed ratio of the rotor, when the distances between the helical turns of the wake become commensurate with the dimensions of their vortex cores. The proposed analytical solution for predicting the axial velocity induced on the blade gives a more accurate determination of a rotor efficiency and optimal operating regimes, as well as uses it in models to assess possible erosion and icing. These results are important for a fundamental understanding and description of the behavior of flows with a system of helical vortices not only in power engineering, but also in other areas where regimes with many vortex helical structures arise, for example, in tornado cores and for axial vortices in vortex apparatuses; cyclone separators, combustion chambers, etc.