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Heat Transfer - Engineering

Q1:

Overall heat transfer co-efficient for cooling of hydrocarbons by water is about

A 50 -100 Kcal/hr.m2.°C

B 50 -100 W/m2 . °K

C 50 -100 BTU/hr. ft.2°F

D 1000 - 1500 BTU/hr. ft.2°F

ANS:C - 50 -100 BTU/hr. ft.2°F

The overall heat transfer coefficient for cooling hydrocarbons by water typically ranges from 50 - 100 BTU/hr. ft^2°F. Explanation:

  • The overall heat transfer coefficient (U) represents the combined resistance to heat transfer across all interfaces involved in the process, including conduction within materials, convection at fluid-solid interfaces, and radiation if applicable.
  • When cooling hydrocarbons (such as oil or petroleum products) with water, heat transfer occurs primarily through convection between the hydrocarbon and the cooling water.
  • The units commonly used for the overall heat transfer coefficient include BTU/hr. ft^2°F, W/m^2°C, and Kcal/hr.m^2.°C. These units represent the rate of heat transfer per unit area per unit temperature difference between the two fluids.
  • In the given options, the range of 50 - 100 BTU/hr. ft^2°F is consistent with typical values for overall heat transfer coefficients in such applications.
Therefore, the overall heat transfer coefficient for cooling hydrocarbons by water is approximately 50 - 100 BTU/hr. ft^2°F.