Conduction occurs in the buffer zone for a fluid flowing through a heated pipe, only when Prandtl number is________________?

A. Temperature gradient of the wall to that across the entire pipe
B. Temperature difference to the temperature gradient at the wall
C. Heat flux at the wall to that across the entire pipe
D. None of these

A. Concentrations
B. Chemical potentials
C. Activity co-efficients
D. Mass transfer co-efficients

A. Tube side pressure drop and the heat transfer rate
B. Convective heat transfer co-efficient
C. Effective tube surface area for convective heat transfer
D. All A. B. and C.

A. 15 min
B. 22 min
C. 44 min
D. 51 min

A. Long vertical evaporator
B. Horizontal tube evaporator
C. Agitated film evaporator
D. Calandria vertical tube evaporator

A. 50 -100 Kcal/hr.m2.°C
B. 50 -100 W/m2.°K
C. 50 -100 BTU/hr. ft.2°F
D. 1000 – 1500 BTU/hr. ft.2°F