Heat transfer and flow analysis of a novel particle heater using CFD-DEM

CFD-DEM coupled simulations of a unique gravity-fed particle heater are performed. Physical and heat transfer properties of the solid particles and walls are varied to determine their relative impact on the local heat transfer coefficient along the heater surfaces. The varied parameters are the coefficient of restitution, particle-particle and particle-wall friction coefficients, particle size distribution, normal spring constant, particle conductivity, particle specific heat, and the numerical lens radius. The local heat transfer coefficient increases when the local void fraction along the heater surface decreases. In addition to analyzing thermal performance, flow instabilities are also identified under certain conditions. The outlet particle flow oscillates when the top of each heater is rounded. For heaters with sharp top edges, the local heat transfer coefficient and void fraction profiles change dramatically. The sharp corners remove the particle stagnation point, and the particles adhere to the surface better which increases the heat transfer.