Page 138 - Applied Process Design For Chemical And Petrochemical Plants Volume III

66131_Ludwig_CH10D 5/30/2001 4:30 PM Page 103

Heat Transfer 103

Figure 10-51. Convection inside film coefficient for gases and low vis-
cosity fluids inside tubes—heating and cooling. (Used by permission:
nd
McAdams, W. H. Heat Transmission, 2 Ed., ©1942. McGraw-Hill, Inc.
All rights reserved.)

Figure 10-50C. Tube-side (inside tubes) liquid film heat transfer coef-
®
ficient for Dowtherm . A fluid inside pipes/tubes, turbulent flow only.
–
2
Note: h average film coefficient, Btu/hr-ft -°F; d i inside tube diam-
eter, in.; G mass velocity, lb/sec/ft ; v fluid velocity, ft/sec; k
2
thermal conductivity, Btu/hr (ft )(°F/ft); viscosity, lb/(hr)(ft);
2
C p specific heat, Btu/(lb)(°F). (Used by permission: Engineering
Manual for Dowtherm Heat Transfer Fluids, ©1991. The Dow Chemi-
cal Co. )

Figure 10-52. Heat transfer to gases inside tubes. (Used by permis-
sion: Buthod, A. P. Oil & Gas Journal, V. 58, No. 3, ©1960. PennWell
Publishing Company. All rights reserved.)

The smallest baffle window is 15—20% of the diameter of
the shell, and the largest is close to 51%. Some design rela-
tions in other references use this as a percentage of the
shell cross-section area, and the corresponding relations
must be used. In exchanger design, this cutout is varied to
Figure 10-50D. Tube-side (inside pipes or tubes) liquid film heat
transfer coefficient for Dowtherm A and E at various temperatures. help obtain good operating performance; however, the
®
(Used by permission: Engineering Manual for Heat Transfer Fluids, spacing between baffles (baffle pitch) is much more signif-
©1991. The Dow Chemical Co.) icant in its effect on the film coefficient for a given baffle