Dimensional Analysis(Heat Transfer ) Questions and Answers

Question 1. Ratio of actual velocity to sonic velocity is known as
  1.    Mach number
  2.    Peclet number
  3.    Reynolds number
  4.    Grashof number
Explanation:-
Answer: Option A. -> Mach number
Answer: (a).Mach number

Question 2. Let us say Mach number (greater than one), the flow is
  1.    Sonic
  2.    Subsonic
  3.    Supersonic
  4.    No flow
Explanation:-
Answer: Option C. -> Supersonic
Answer: (c).Supersonic

Question 3. Free convection heat flow does not depends on
  1.    Density
  2.    Coefficient of viscosity
  3.    Gravitational force
  4.    Velocity
Explanation:-
Answer: Option B. -> Coefficient of viscosity
Answer: (b).Coefficient of viscosity

Question 4. The value of Prandtl number for air is about
  1.    0.1
  2.    0.4
  3.    0.7
  4.    1.1
Explanation:-
Answer: Option C. -> 0.7
Answer: (c).0.7

Question 5. Which dimensionless number has a significant role in forced convection?
  1.    Prandtl number
  2.    Peclet number
  3.    Mach number
  4.    Reynolds number
Explanation:-
Answer: Option D. -> Reynolds number
Answer: (d).Reynolds number

Question 6. The non-dimensional parameter known as Stanton number is used in
  1.    Forced convection heat transfer
  2.    Condensation heat transfer
  3.    Natural convection heat transfer
  4.    Unsteady state heat transfer
Explanation:-
Answer: Option A. -> Forced convection heat transfer
Answer: (a).Forced convection heat transfer

Question 7. Heat is loss from a 100 mm diameter steam pipe placed horizontally in ambient air at 30 degree Celsius. If the Nusselt number is 25 W/m² K and thermal conductivity of the air is 0.03 W/m K, then heat transfer coefficient will be
  1.    7.5 W/m² K
  2.    16.5 W/m² K
  3.    25 W/m² K
  4.    30 W/m² K
Explanation:-
Answer: Option A. -> 7.5 W/m² K
Answer: (a).7.5 W/m² K

Question 8. The Prandtl number will be lowest for
  1.    Water
  2.    Liquid metal
  3.    Lube oil
  4.    Aqueous solution
Explanation:-
Answer: Option B. -> Liquid metal
Answer: (b).Liquid metal

Question 9. The dimensionless parameter l³ p² β g d t/µ² is referred to as
  1.    Stanton number
  2.    Schmidt number
  3.    Grashof number
  4.    Peclet number
Explanation:-
Answer: Option C. -> Grashof number
Answer: (c).Grashof number

Question 10. Ratio of inertia force to viscous force is known as
  1.    Grashof number
  2.    Reynolds number
  3.    Peclet number
  4.    Stanton number
Explanation:-
Answer: Option B. -> Reynolds number
Answer: (b).Reynolds number