Structure of a fixed and a fluidized bed of granular material near an immersed surface (wall)

Study of wall-to-bed heat transfer in a bubbling fluidised bed using the kinetic theory of granular flow

“…An effective model by Martin [36] was modified to assume the ratio of the solids maximal porosity and the bulk porosity was constant [8]. This agreed well with experimental data taken from Korolev et al [37].…”

Numerical calculation of wall‐to‐bed heat‐transfer coefficients in gas‐fluidized beds

“…However, due to the bed voidage variation near the constraining heat-transfer surface, the thermophysical properties of the packet close to the surface will differ from those in the bulk of the emulsion phase. In fluidized beds the principal voidage variation occurs within one particle diameter from the surface (Korolev et al, 1971) which implies that the thickness of the surface layer of altered thermophysical properties is approximately one particle diameter. Most probably, the effect of this surface layer or packet heterogeneity is negligible for packets with a heat penetration depth 6>> dp, thus for packets with relatively large residence times.…”

Wall‐to‐bed heat transfer in gas–solid bubbling fluidized beds

“…Korolev et al15 measured the (average) local porosity in a fluidized bed near a surface. In Figure 3 the measured local porosity ϵ loc relative to the bulk porosity ϵ 0 for packed beds is plotted as a function of the relative distance to the surface x / d p for both a wall and an immersed surface and for different fluidization velocities, showing that the local porosity for both the wall and the immersed surface is dependent on the fluidization velocity.…”