Food Engineering Questions and Answers – Unit Operations – Heat Transfer by Convection-2

This set of Food Engineering Interview Questions & Answers focuses on “Heat Transfer by Convection-2”.

1. According to Nusselt’s film theory, the film thickness decreases as we move from bottom to top. The heat transfer increases.
a) True
b) False
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2. Statement 1: Unsteady state heat transfer equation can be used when there is negligible internal resistance.
Statement 2: Unsteady state heat transfer equation can be used for liquid food items which are well stirred, because, temperature gradient within won’t be there.
a) True, False
b) True, True
c) False, False
d) False, True
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3. Statement 1: In nusselt’s film theory, velocity of the falling film is not affected by the velocity of the vapors.
Statement 2: LMTD can be used provided the overall heat transfer co-efficient is constant over a large range of temperatures.
a) True, False
b) True, True
c) False, False
d) False, True
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4. Find heat transfer in an agitated jacketed vessel if N_Rei is 1.5 * 105 and N_Pr is 20.
a) 0.9
b) 1.2
c) 1.8
d) None of the mentioned
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5. Which of the following is NOT a real dimensionless number?
a) Pectit number
b) Stanton number
c) Graetz number
d) Grashof number
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6. Statement 1: N_Pr= (C_pm)/kl
Statement 2: Stanton number is a product of N_Re and N_Pr.
a) True, False
b) True, True
c) False, False
d) False, True
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7. Statement 1: G is known as the mass flux and it is the product of density and velocity.
Statement 2: Grashof number is associated with forced convection.
a) True, False
b) True, True
c) False, False
d) False, True
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8. Ф_v is generally taken as 1 in food processing as generally very high wall temperatures aren’t reached and hence (µ/µ_w) * 0.14 is 1 as there isn’t much difference in µ and µ_w.
a) True
b) False
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9. Statement 1: Sieder-Tate and Dittus-boelter equations imply only to laminar flow conditions.
Statement 2: Under laminar conditions, the same equation applies both to Newtonian and Non-Newtonian fluids.
a) True, False
b) True, True
c) False, False
d) False, True
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10. Dittus-boelter equation is applicable for fluids with phase change.
a) True
b) False
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Sanfoundry Global Education & Learning Series – Food Engineering.

To practice all areas of Food Engineering for interviews, here is complete set of 1000+ Multiple Choice Questions and Answers.

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