The paper reports an experimental and numerical analysis of the iso-thermal flow field within a solar vortex receiver-reactor, termed the Solar Expanding-Vortex particle Reactor, SEVR, together with an assessment of its propensity to mitigate particle deposition onto the receiver-reactor window, with the aim to assess the validity of an aerodynamic mechanism previously proposed. The influence of the dominant reactor geometrical parameters, particle size and load on the vortex structure and particle deposition onto the receiver-reactor window was investigated. It was found that the SEVR can be configured to substantially mitigate the particle deposition in comparison with the previous state-of-the-art of solar vortex receiver-reactor. Furthermore, the experimental results confirmed the aerodynamic mechanism previously proposed, in which two critical parameters controlling the propensity of particles to penetrate into the secondary concentrator chamber are the intensity of the vortex at the plane of the aperture and the diameter of the vortex core at the aperture plane relative to the aperture diameter. (C) 2016 Elsevier Ltd. All rights reserved.