A. Grashoff no. and Reynold no
B. Grashoff no and Prandtl no.
C. Prandtl no. and Reynold no
D. Grashoff no., Prandtl no and Reynold no
E. none of the above
Related Mcqs:
- In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by___________________?
A. convection
B. radiation
C. conduction
D. both convection and conduction
E. none of the above - The concept of overall coefficient of heat transfer is used in case of heat transfer by________________?
A. conduction
B. convection
C. radiation
D. conduction and convection
E. convection and radiation - When heat is transferred form hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by __________________?
A. conduction
B. convection
C. radiation
D. conduction and convection
E. convection and radiation - When heat is Transferred by molecular collision, it is referred to as heat transfer by __________________?
A. conduction
B. convection
C. radiation
D. scattering
E. convection and radiation - When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by ___________________?
A. conduction
B. convection
C. radiation
D. conduction and convection
E. convection and radiation - In regenerator type heat exchanger, heat transfer takes place by___________________?
A. direct mixing of hot and cold fluids
B. a complete separation between hot and cold fluids
C. flow of hot and cold fluids alternately over a surface
D. generation of heat again and again
E. indirect transfer - In heat exchangers, degree of approach is defined as the difference between temperatures of________________?
A. cold water inlet and outlet
B. hot medium inlet and outlet
C. hot medium outlet and cold water inlet
D. hot medium outlet and cold water outlet
E. none of the above - Which of the following is a case of steady state heat transfer ___________________?
A. I.C. engine
B. air preheaters
C. heating of building in winter
D. all of the above
E. none of the above - Heat is transferred by all three modes of transfer, viz, conduction, convection and radiation in _________________?
A. electric heater
B. steam condenser
C. melting of ice
D. refrigerator condenser coils
E. boiler - A non-dimensional number generally associated with natural convection heat transfer is________________?
A. Grashoff number
B. Nusselt number
C. Weber number
D. Prandtl number
E. Reynold number
