INDUSTRIAL AND ENGINEERING CHEMISTRY Keilen, J. J., Dougherty, K.I>k,, the bracket ( 7 ) becomes merely (3/P) - 2. To eliminate F2, one may writc ki
- L,
=
(kj1Ti
- k/272)
(2)
Data to test these relations are scarce. Schncider of the Kational Research Council of Canada recently furnished the writer with density and porosity data from the thesis of Weininger, which made possible testp of the above relations with their data (5’)on alumina and borosilicate glass beds with different gases. The gas thermal conductivities used by the writcr for the computations are froin a compilation by Ileyes (11: 30” C. k X IO’, cal./cm. Hydrogen Helium Xitrogen Carbon dioxide
see. ’C. 4.34 3.58 0.624 0.402
The results are shown in Table I. Xote that reasonably good agreement is found between experimental and theoretical results when kl is several times greater than kp. I n the calculations, k, for alumina was assumed high and the relation 7 = ( 3 / P ) - 2 was used. However, k, = 0.0026 was used for borodicate glass and ri were calculated for each gas. It is tempting to assume that F2 is given by the vacuum con-
TABLE I. EXPERIMENTAL VERSUS CALCULATED T H E R M A L CONDCCTIVITIES’ ki-ka
Aluniina 16 mesh’
P = 0.432 G a 5 ~
Esptl.
2.55 16.87 He-&*> 14.32 HrC02 18.66 16.10 He-CO? s2-coz 1.78 lo4 om. sec. IIr-He H2-S*
‘
Calod.
Aliimina, 36 mesh
P
=
Erptl.
104 cal./cni. sec. 3.76 2.32 16.73 18.37 14.41 14.61 19.47 18.74 15.71 16.42 1.10 2.01
0.461 Cdcd.
Borosiliclttc glass, 30 mesh
P = 0.689 Calcd.
Exptl.
C. 3.43 16.75 13.33 17.75 14.33 1.00
0.74 5.90 5.16 7.11 6.37 1.21
1.04
6.09 5.05 6.57 6.53 0.48
ductivity of the bed. However, in the writcr’s experience nith these data and those cited in previous papers, this is frequently disappointing, and further data probably will be necessary. Reference should be made to the papers cited for details and for statements as to the requirements of data for testing surh relationships. The writer thanks Dr. Schiieider for supplying the density a n d porosity data and for his interest in the problem. LITERATURE CITED
(1) Keyes, T’. G., personal communication, 1949. (2) Strickler, H. S.,J . Chem. Phys., 20, 1333-4 (1952). (3) Weininger, J. I,., and Schneidcr, ‘K. 0.. I K D .ESG. CHEM.,43, 1229-33 (1951).
H. S. S T H I C K l . l ~ R WILLIAVH. SINGERMEMORI.AL R E ~ E A R CL
