Numerical analysis of flow field in three-dimensional randomly packed pebble-bed channel

The numerical simulations were performed on the water flow through three dimensional randomly packed pebble-bed channel, and the impacts of different flow conditions upon distribution of the radial velocity of cut section in packed channel were analyzed as well as different cut sections. The distinct element method was used to generate random packing structure, and the bridged method was used to deal with the contact issue of the particle to particle and particle to wall. The results show that using bridged method, the influence in porosity is negligible; the velocity in the cross section in packed channel has a similar radial distribution to porosity. The more distance away from channel wall, the worse consistency of the velocity distribution of different cross-sections. With the Reynolds number increase, the velocity distribution of the cross-section becomes uniform. (authors)