Boiling and condensation

King Saud UniversiyCollege of Engineering

Chemical Engineering DeptmentChE 313 ChE 317Heat Transfer Operations

Boiling

Boiling

Film boiling

Example: Film boiling

Example: Film boiling

Example: Film boiling

Q1Water is being boiled at 1 atm abs pressure in a jacketed kettle with steam condensing in the jacket at 115.6 ºC. The inside diameter of the kettle is 0.656 m and the height is 0.984 m. The bottom is assumed to be flat. Both the bottom and the sides up to a height of 0.656 m are jacketed. The kettle surface for heat transfer is 3.2-mm stainless steal with a k of 16.27 W/m. K. Predict the boiling heat-transfer coefficient for the vertical jacketed sides of the kettle. Also predict the total heat transfer if the boiling heat-transfer coefficient for the bottom surface of the kettle is 2955 W/m2.K.

hsteam =10200W/m2K

King Saud University ChE 313College of Engineering Tutorial # 7Chemical Engineering Dept. 10/5/1431

Heat Transfer Operations

Q2

steam saturated at 68.9 kPa (10 psia) is condensing on a vertical tube 1.22 m (4.0 ft) long having an OD of 0.0254 m (1.0 in.) and a surface temperature of 86.11 ºC (187 ºF). Calculate the average heat-transfer-coefficient using English and SI units.

King Saud University ChE 317College of Engineering Tutorial # 5Chemical Engineering Dept.

Heat Transfer Operations