What is Nusselt number ?

Related Mcqs:

1. In forced convection, the Nusselt number is a function of ____________________?

   A. Re and Pr
   B. Re and Gr
   C. Pr and Gr
   D. Re and Sc

2. Nusselt number is the ratio of the temperature gradient at the wall to_________________?

   A. Temperature difference
   B. Heat flux
   C. That across the entire pipe
   D. None of these

3. The Sieder-Tate correlation for heat transfer in turbulent flow in pipe gives Nu α Re0.8, where, Nu is the Nusselt number and Re is the Reynolds number for the flow. Assuming that this relation is valid, the heat transfer co-efficient varies with the pipe diameter D. as _________________?

   A. D-1.8
   B. D-0.2
   C. D0.2
   D. D1.8

4. Nusselt number is a function of Prandtl number and ______________ number of fluid in natural convection heat transfer?

   A. Grashoff
   B. Biot
   C. Stanton
   D. Reynolds

5. The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is__________________?

   A. 2.36
   B. 4.36
   C. 120.36
   D. Dependent on NRe only

6. Nusselt number is the ratio of the ____________________?

   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

7. Value of Nusselt number [Nu = (hD/k)] for the heat transfer by conduction from a droplet or a spherical particle to a surrounding stagnant film is__________________?

   A. 0.5
   B. 2
   C. 10
   D. 100

8. Nusselt number (for forced convection heat transfer) is a function of the _____________ number?

   A. Prandtl
   B. Reynolds
   C. Both A. & B.
   D. Neither A. nor B.

9. The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is______________?

   A. 1.66
   B. 88.66
   C. 3.66
   D. Dependent on NRe only

10. Convective heat transfer, in which heat is transferred by movement of warmed matter is described by___________________?

    A. Fourier’s law
    B. Newton’s law of cooling
    C. Fick’s law
    D. None of these