Free and Forced Convection during internal flow through tubes

Which of the following has the highest convective heat transfer coefficient for internal flow in tubes?

• Laminar flow
• Turbulent flow
• Transition flow
• None of the above

The heat transfer coefficient for turbulent flow in a tube with an increase in the Reynolds number, will:

• Increase
• Decrease
• Remain constant
• Increase at first and then decrease

What is the type of flow in a tube if the Reynolds number is less than 2300?

• Laminar
• Turbulent
• Transition
• None of the above

Which of the following affects the Nusselt number for turbulent flow in a tube?

• Prandtl number, Reynolds number
• Reynolds number, tube diameter
• Viscosity, tube diameter
• Reynolds number, Prandtl number

At what Reynolds number does the flow change from laminar to turbulent flow in a tube?

• 2300
• 3500
• 4000
• 5000

Which of the following describes the heat transfer coefficient in the entrance region for laminar flow in a tube?

• Increases linearly
• Increases exponentially
• Remains constant in the region
• Decreases linearly