Heat Transfer Questions and Answers – Reynolds Number

This set of Heat Transfer Multiple Choice Questions & Answers (MCQs) focuses on “Reynolds Number”.

1. The ratio of inertia force to viscous force is known as
a) Grashof number
b) Reynolds number
c) Fourier number
d) Nusselt number
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2. Velocity within the given fields would be similar in magnitude, direction and turbulence pattern when
a) Nusselt number are different
b) Nusselt number are same
c) Reynolds number are different
d) Reynolds number are same
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3. Reynolds number is given by the quantity
a) p V l/δ
b) 2 p V l/δ
c) 3 p V l/δ
d) 4 p V l/δ
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4. Air enters a rectangular duct measuring 30 cm by 40 cm with a velocity of 8.5 m/s and a temperature of 40 degree Celsius. The flowing air has a thermal conductivity 0.028 W/m K, kinematic viscosity 16.95 * 10 ^-6 m²/s and from empirical correlations the Nusselt number has been approximated to be 425. Find out the flow Reynolds number
a) 1.1719 * 10 ⁶
b) 2.1719 * 10 ⁶
c) 0.1719 * 10 ⁶
d) 4.1719 * 10 ⁶
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5. In a rectangular duct with a flow velocity of 8.5 m/s, temperature of 40°C, and Nusselt number of 425, the thermal conductivity is 0.028 W/m·K and the kinematic viscosity is 16.95 × 10^-6 m²/s. Find the convective heat flow coefficient.
a) 24.71 W/m² K
b) 34.71 W/m² K
c) 44.71 W/m² K
d) 54.71 W/m² K
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6. For laminar flow, Reynolds number should be
a) Less than 2300
b) Equal to 2300
c) Greater than 2300
d) Less than 4300
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7. For turbulent flow, Reynolds number must be
a) Less than 5000
b) Equal to 6000
c) Less than 6000
d) Greater than 6000
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8. What is the value of convective coefficient of air and superheated steam in case of forced convection?
a) 30-900 W/m² K
b) 30-700 W/m² K
c) 30-300 W/m² K
d) 30-400 W/m² K
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9. Heat is being transferred by convection from water at 48 degree Celsius to glass plate whose surface is exposed to water at 40 degree Celsius. The thermal conductivity of water is 0.6 W/m K and the thermal conductivity of glass is 1.2 W/m K. The spectral gradient of temperature in the water at the water glass interface is 10 ^-4 K/m. The heat transfer coefficient in W/m² K is

a) 0.0
b) 750
c) 6.0
d) 4.8
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10. For transient flow, the value of Reynolds number may vary between
a) 1450-9870
b) 1200-4500
c) 2300-6000
d) 6000-9000
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Sanfoundry Global Education & Learning Series – Heat Transfer.

To practice all areas of Heat Transfer, here is complete set of 1000+ Multiple Choice Questions and Answers.