. Transactions . f one cubic meter of air, . . i<ilogrammes. Average velocity, .... meters and meters. Loss of head, ram. and mm. x= mm. and Average value of a;, ....... The coefficient of the loss of head shows an increase that is hardto explain. Doubtless the undulations were greater than with theprevious experiments, and the surface irregularities, due to thespaces between the sets, were relatively of greater importance; never-theless it would be impossible to explain such an increase except forthe influence of the reduced sections of w
. Transactions . f one cubic meter of air, . . i<ilogrammes. Average velocity, .... meters and meters. Loss of head, ram. and mm. x= mm. and Average value of a;, ....... The coefficient of the loss of head shows an increase that is hardto explain. Doubtless the undulations were greater than with theprevious experiments, and the surface irregularities, due to thespaces between the sets, were relatively of greater importance; never-theless it would be impossible to explain such an increase except forthe influence of the reduced sections of which we have spoken sooften. From the results which we obtained, it would appear thatthis influence is particularly potent in timbered gangways. Conclusion.—The two values for the coefficient of loss of headdetermined in straight and normal timbered passages, represent thetwo extremes of actual practice, viz. : for new workings, and for old loss of head of AlK-CURRENTS. 105 Fig. 20. Curves of equal Velocity. EXPERIMENT No. 12. (November 25th, 1892.) TimDered Gang^A^ay, Small Section. CREAL MINE FOURTH FLOOR. Scale iv Feet and Meters. MeUra, ! 9 6 3 No. VELOCITIES OBSERVED. Meters I 2 2914 3 2-814 4 1-932 S 6 7 Meters ... ,.. Average Velocity meters, Area of Gangway sq. meters, Volume Discnarged cub. meters, M aximum Velocity Ritio of Maximum to Average Velocity. .meters, 106 loss of head op aircurrexts. and frequently repaired gangways. For general use we may safelyuse their average, viz.: .^^ This value increases rapidly as the cross-sectional area decreases,and, in the single case of small-section passages that we observed, itreached We may add that this gangway was slightlysinuous. VII.—General Conclusions. Becapiiulated Table.—In order to facilitate a comparison of theresults of our twelve observations, we have assembled them in t
Size: 1707px × 1463px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
