By using beds of glass fiber with adiameter of 4-270μ as shown in Table 1, we investigated the various pressure drop characteristics and obtained the following results.
(1) Pressure drops of the fiber mats decrease with the reduction of the area ratio A_i/A₀, i.c. area ratio of masked face area to initial face area of the fiber mat. And the pressure drop Δp_f changes with filter thickness L or fiber diameter D_f (Figs. 5, 6, 7 & 8). (2) From the definition of a drag coefficient of a fiber mat, the experimental drag coefficient C_D, were obtained, and Correlated with Reynolds number NRe. (Fig. 9) The results are represented by the empirical Eq. (5) or (6).
In case 10^-3 N_Re 1.5×1010^-3
C_De=0.6+4.7/√N_Re+11N_Re Eq. (5)
(3) In Fig. 9, the curved line shows the vaLues calculated from Eq. (5), which are in agreement with the experimental data. Comparison was made between these values and those obtained from other investigators' equations, and the Iberalls' equation was found to be in agreement with ours in case NRe 1. When NRe 1, however, all the values obtained from other investigators' equations deviated from the experimental data.
(4) The pressure drops of the fiber mats were proportional to (1-ε)^m in our experiments (Eq. 7). When this relation is introduced in to Eq. (4), in the place of (1-ε), we may call it a modifid drag coefficient C_Dm. The correlations of C_Dm vs. N_Re can be given by Fig. 12 in the same way as by Fig. 9, and the experimental data fall exactly on the straight line when N_Re 1(C_Dm∝N_Re^-1), and they show tendencies similar to frictional factors of acircular pipe for the turbulent region when N_Re 1 (Eq. 8).

View full abstract

A limited amount of viscosity and thermal conductivity data at high pressures have been utilized along the lines proposed by Owens and Thodos³⁴ to predict the viscosity and thermal conductivity of diatomic gases at elevated pressures and the liquid state. In addition, the available subatmospheric viscosity data of Johnston, Mattox and Powers¹⁹ for nitrogen have permitted the extension of this study to include pressures as low as 0.01mm of mercury.
Reduced state correlations of viscosity and thermal conductivity have been constructed from the data available for nitrogen. These correlations are capable of predicting these properties in the gaseous and liquid states for other diatomic gases.

View full abstract

The main objectives of this work were, first to see whether an unsteady-state diffusion theory was applicable to mass transfer into a liquid film flowing over the surface of a packing piece such as a Raschig ring or a Berl saddle, and, second, to obtain a general correlation for liquid phase mass transfer coefficients of these packings.
Absorption of pure carbon dioxide by three solvents, water, methanol and n-butanol, were carried out in a column, where single pieces of Raschig rings or Berl saddles were located as shown in Fig. 1. Figs. 2 and 3 show the values of HL for a Raschig ring in case θ is 45°. When the values of (HL/z)·(Ga1/6/Sc1/2) are calculated from these data and plotted against Re as shown in Figs. 4 and 5, the data points for all runs come on a single line as represented by Eq. (5). These results indicate that mass transfer into a liquid film flowing over the packing pieces closely follows predictions based on the unsteady-state diffusion theory. Figs. 6, 7 and 8, similar to Figs. 4 and 5, show the results given with a Raschig ring (θ=90°), with a short wetted-wall column corresponding to a Raschig ring (θ=0°) and with a Berl saddle (θ=45°), respectively. The best lines through the data in these figures are expressed by Eqs. (6), (7) and (8), respectively. Taking the variation of HL with θ into account, Eqs. (19) and (20), giving the average values of HL for single pieces of Raschig rings and Berl saddles, have been obtained.
In order to determine the effect of Schmidt number on HL for packed columns, additional experiments on the absorption of pure solute gases, hydrogen, oxygen and carbon dioxide, by water were carried out in a 7.0cm column packed with 15mm Raschig rings. Experimental results indicate that the values of HL vary as the 1/2 power of the Schmidt number, in agreement with the unsteadystate diffusion theory.

View full abstract