Numerical and experimental investigation of a novel multi-stage falling particle receiver

A new particle receiver design employing a novel multi-stage falling concept is introduced along with numerical and experimental investigation. The multi-stage falling particle receiver increases the particle residence time and the average particle volume fraction in the receiver by means of regularly-spaced troughs to collect falling particles and reinitialize the falling. Preliminary CFD simulation showed particle falling hydrodynamics in the presence of troughs. Absorptance of solar radiation for different free falling heights was simulated and correlated to identify required number of stages to maintain the absorptance above a desired level. The benefit of the multi-stage falling concept becomes obvious and more significant as the particle flow rate (in kg/s-m) decreases and the particle size increases. Experimental investigation was done though a number of cold particle falling tests in different conditions using a 5m high and 0.8m wide falling test rig. The falling test visually revealed the problems caused by accelerated long free falling emphasizing the benefit of the multi-stage falling concept.