The influences of superficial velocity (u) and granular layer thickness (L) on the granular bed filtration performances were investigated in a cold-state experimental apparatus using two kinds of filter media.Combined with the macroscopic model of granular bed filtration

the effects of the specific mass deposit (σ) on the deviation degree (F and G) of dust collecting ability and pressure drop with initial values under different operation conditions were analyzed.On this basis

the prediction of filter efficiency and pressure drop was performed.The results revealed that F increased at first and then decreased with increasing of σ

while G presented a linearly increase trend.The functional relationship between F(G) and σ was established by combination with experimental data under the condition of u=0.2~0.6 m·s-1 and L=0.11~0.2 m.The calculations of the proposed formulas were in a good agreement with experiments

which were better than the formulas provided in the literature

and thus could provide some guidance for the prediction of performances of granular bed filters.