Convective Heat Transfer and Particle Dynamics in Lattice Frame Configuration: Effect of Lattice Porosity and Particle Size

Abstract In this study, we have characterized the convective heat transfer due to the movement of particles through a lattice frame configuration comprised of an array of 5 × 5 unit cells of Octet topology. The unit cell porosity was varied between 0.75 and 0.88. The test coupons were additively manufactured using Binder jet technique in stainless steel 316 L. The convective heat transfer coefficients were determined via quasi-steady-state experiments conducted on a particle elevator and heat exchanger test facility, which provided a continuous supply of particles at desired flowrates. The heat transfer experiments were conducted for particle mass flux upto ∼100kg/m2s, which encompassed both packed bed and loose bed flow configurations. The heat transfer experiments were conducted with two different sets of CARBOBEAD particles, with mean diameters of 266 µm and 397 µm. Further, to understand the particle movement near the endwall, optical flow experiments were also conducted for the 397 µm particles to determine the near-wall particle velocity field using the Farneback algorithm. The results indicate that lattice porosity has a dominant effect on the convective transport, while smaller-sized particles supported better heat transfer.