## Heat Transfer Miscellaneous

#### Heat-Transfer

1. The Blausius equation related to boundary layer theory is a

1. Blausius equation:

 2d3f + fd²f = 0 dη3 dη²

This order non-linear D.E.

##### Correct Option: D

Blausius equation:

 2d3f + fd²f = 0 dη3 dη²

This order non-linear D.E.

1. ##### Correct Option: C

1. A thin vertical flat plate of height L, and infinite width perpendicular to the plane of the figure, is losing heat t o t he sur r oundi ngs by nat ur al convection. The temperature of the plate and the surroundings, and the proper ties of t he surrounding fluid, are constant. The relationship bet ween t he average Nussel t and Rayl ei gh numbers is given as Nu = K Ra1/4, where K is a constant. The lengt h scales for Nusselt and Rayleigh numbers are the height of the plate. The height of the plate is increased to 16L keeping all other factors constant

If the average heat transfer coefficient for the first plate is h1 and that for the second plate is h2, the value of the ratio h1 /h2 is

1. ##### Correct Option: A

1. Consider one-dimensional steady state heat conduction, without heat generation, in a plane wall; with boundary conditions as shown in the figure below. The conductivity of the wall is given by k = k0 + bT; where k0 and b are positive constant, and T is temperature.

As x increases, the temperature gradient (dT/dx) will

1. ##### Correct Option: A

1. Consider one-dimensional steady state heat conducting along x-axis (0 ≤ x ≤ L), through a plane wall with the boundary surfaces (x = 0 and x = L) maintained at temperature of 0°C and 100°C. Heat is generated uniformly through out the wall. Choose the CORRECT statement