Forced External Convection

Question 1

Given a flat plate with external forced convection and constant surface temperature, how do you find area of greatest heat transfer?

Answer 1

1. Calculate transition point for turbulent flow
2. Investigate key points where heat coefficient might be greatest
3. Heat coefficient can be determined from the Nusselt (use Internal forced convection chart)

Question 2

Given external forced convection over tube banks, how do you find the refrigeration capacity and the pressure drop across the tube bank?

Answer 2

1. Find u_max using continuity equation
2. Find the reynolds number for the u_max
3. Use Proper Relation for tube bank to find Nusselt Number
4. Use nusselt number to find heat transfer coefficient
5. Find logarithmic mean temperature difference and calculate q
6. For pressure drop just use formula and graph