Tham khảo tài liệu 'perry s chemical engineers phần 5', kỹ thuật - công nghệ, hoá học - dầu khí phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 6-38 FLUID AND PARTICLE DYNAMICS FIG. 6-43 Friction factors for in-line tube banks. From Grimison Trans. ASME 59 583 1937 . pressure drop with laminar flow Re 100 of liquids across banks of plain tubes with pitch ratios P Dt of and 4 p ạ 6k y hpyk 6-164 Re P w 2 arrangements and other quantities are as defined following Eq. 6-163 . Bergelin et al. ibid. show that pressure drop per row is independent of the number of rows in the bank with laminar flow. The pressure drop is predicted within about 25 percent. m ------ Re 6-165 where Re D Vmaxp LU D volumetric hydraulic diameter 4 X free-bundle volume exposed surface area of tubes P pitch a for in-line arrangements a or c whichever is smaller for staggered FIG. 6-44 Friction factors vs. transverse spacing for single row of tubes. From Boucher and Lapple Chem. Eng. Prog. 44 117 1948 . FIG. 6-45 Friction factors for transition region flow across tube banks. Pitch is the minimum center-to-center tube spacing. From Bergelin Brown and Doberstein Trans. ASME 74 953 1952 . FLUID DYNAMICS 6-39 FIG. 6-46 Friction factor for beds of solids. From Leva Fluidization McGraw-Hill New York 1959 p. 49. The validity of extrapolating Eq. 6-164 to pitch ratios larger than is unknown. The correlation of Gunter and Shaw Trans. ASME 67 643-660 1945 may be used as an approximation in such cases. For laminar flow of non-Newtonian fluids across tube banks see Adams and Bell Chem. Eng. Prog. 64 Symp. Ser 82 133-145 1968 . Flow-induced tube vibration occurs at critical fluid velocities through tube banks and is to be avoided because of the severe damage that can result. Methods to predict and correct vibration problems may be found in Eisinger Trans. ASME J. Pressure Vessel Tech. 102 138-145 May 1980 and Chen J. Sound Vibration 93 439-455 1984 . BEDS OF SOLIDS Fixed Beds of Granular Solids Pressure-drop prediction is complicated by the variety of granular materials and of their packing arrangement. For flow of a .
