The volumetric particle solar receiver geometry and dimensions is depicted in Figure 1. A particle suspension is injected near the aperture from a narrow circumferential slit in a radial-tangential direction, mixes with a secondary particle-free axial stream issued at the aperture. Concentrated solar energy is introduced at the aperture, and it is absorbed by the particles. Heat is transferred from the particles to the work fluid by convection. The hot suspension is leaving at the conical nozzle outlet. The walls exchange energy by radiation and convection.