Liquid holdup and interfacial areas were measured in packed columns with cocurrent downward flow. An empirical equation of liquid holdup Φ_t is presented in terms of Reynolds numbers of gas Re_g(=d_sG_g/μ_g) and liquid Re_l, surface shape factor of packing φ, void fraction ε and ratio of packing to column diameter d_p/T, where the ratio is smaller than 0.13. This equation is different for the dispersed bubble flow and other flow regions.
The empirical equation of interfacial area a_p in the respective flow regions varies as follows:
a_pd_p/(1-Φ_l/ε)=ωΦ^-mReⁿ_lRe^q_g(d_p/T)^-t
where ω=7.5×10^-5, m=Q.2, n=Q.15, q=2/3, t=2.5 for spray flow; ω=2.2×10^-4, m=0.3, n=2/3, q=0.2, t=2.5 for pulse flow; ω=3.9×10^-3, m=0.1, n=0.4, q=p. t=2 for trickle flow; ω=2.8×10^-7, m=0.9, n=1.8, q=0, t=3.3 for dispersed bubble flow.
The equation of the boundary in the respective flow regions was found by equating the two of them. The predicted boundaries are in excellent agreement with the literature data given from the analysis of liquid pulse frequencies. The predictions for interfacial areas also agree well with the literature data.