Patent ID: 7209871

Claim:
A computer based method for determining cavity size in packed bed systems, the method comprising: a) retrieving data parameters related to material properties of a packed bed system, the parameters including at least: a blast furnace radius (W), an effective bed height (H), a blast velocity (v b ), a tuyere opening (D t ) a void fraction (ε), a gas viscosity (μ g ), a particle size (d p ), a shape factor (Φ s ), a density of gas (ρ g ), a density of solid (ρ s ), a coefficient of wall friction (μ w ), an acceleration due to gravity (g), an effective particle diameter given by d eff =d p Φ s , an effective bed density given by ρ eff =ερ g +(1−ε)ρ s , a wall-particle frictional coefficient given by μ w =tan Φ w , wherein Φ w is an angle of friction between the wall and the particle, wherein D r is a cavity diameter, and wherein all units are in SI: b) determining a cavity radius (R) for both increasing gas velocity and decreasing gas velocity, the determined cavity radius given by: 2 ⁢ nR 2 - 2 ⁢ nHR + pn ⁢ ⁢ β ⁢ ⁢ v b 2 ⁢ D T 2 2 ⁢ π 2 ⁢ M ⁢ { ln ⁢ ⁢ W 2 ⁢ π - ln ( R - D T 2 ⁢ π } + ( 2 ⁢ r o M ⁢ ⁢ π ⁢ ( α + β ⁢ ⁢ v H ) ⁢ v H ⁡ ( H - r o ) - F wd M ⁢ ⁢ π ) = 0 ⁢ ⁢ and ( 29 ) 2 ⁢ nR 2 - 2 ⁢ nHR + pn ⁢ ⁢ β ⁢ ⁢ v b 2 ⁢ D T 2 2 ⁢ π 2 ⁢ M ⁢ { ln ⁢ ⁢ W 2 ⁢ π - ln ( R - D T 2 ⁢ π } + ( 2 ⁢ r o M ⁢ ⁢ π ⁢ ( α + β ⁢ ⁢ v H ) ⁢ v H ⁡ ( H - r o ) + F wd M ⁢ ⁢ π ) = 0 ( 28 ) respectively; c) determining a cavity size using the cavity radius obtained in step (b); and d) storing the determined cavity size in a memory.