In heat exchangers, degree of approach is defined as the difference between temperatures of________________?

Related Mcqs:

1. Heat conducted througfi unit area and unit thick face per unit time when temperature difference between opposite faces is unity,is called__________________?

   A. thermal resistance
   B. thermal coefficient
   C. temperature gradient
   D. thermal conductivity
   E. heat-transfer

2. In free con-vection heat transfer, Nusselt number is function of________________?

   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

3. The energy distribution of an ideal reflector at higher temperatures is largely in the range of ___________________?

   A. shorter wavelength
   B. longer wavelength
   C. remains same at all wavelengths
   D. wavelength has nothing to do with it
   E. none of the above

4. 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

5. 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

6. 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

7. Total heat is the heat required to__________________?

   A. change vapour into liquid
   B. change liquid into vapour
   C. increase the temperature of a liquid or vapour
   D. convert water into steam and superheat it
   E. convert saturated steam into dry steam

8. 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

9. LMTD in case of counter flow heat exchanger as compared-to parallel flow heat exchanger is _________________?

   A. higher
   B. lower
   C. same
   D. depends on the area of heat exchanger
   E. depends on temperature conditions

10. 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