Questions from Thermal Fluid Science

Q: In a geothermal power plant, the used geothermal water at 80

In a geothermal power plant, the used geothermal water at 80°C enters a 15-cm-diameter and 400-m-long uninsulated pipe at a rate of 8.5 kg/s and leaves at 70°C before being reinj...

Q: Consider a hot boiled egg in a spacecraft that is filled with

Consider a hot boiled egg in a spacecraft that is filled with air at atmospheric pressure and temperature at all times. Will the egg cool faster or slower when the spacecraft is in space instead of on...

Q: A 5-mm-diameter electrical transmission line carries an electric

A 5-mm-diameter electrical transmission line carries an electric current of 50 A and has a resistance of 0.002 ohm per meter length. Determine the surface temperature of the wire during a windy day wh...

Q: Reconsider Prob. 20–29. Using appropriate software, investigate

Reconsider Prob. 20–29. Using appropriate software, investigate the effects of the room temperature and the emissivity of the board on the temperature of the hot surface of the board...

Q: Reconsider Prob. 19–42. Using appropriate software, investigate

Reconsider Prob. 19–42. Using appropriate software, investigate the effect of the wind velocity on the surface temperature of the wire. Let the wind velocity vary from 10 km/h to 80...

Q: Consider a thin 24-cm-long and 20-cm

Consider a thin 24-cm-long and 20-cm-wide horizontal plate suspended in air at 20°C. The plate is equipped with electric resistance heating elements with a rating of 20 W. Now the heater is...

Q: A long aluminum wire of diameter 3 mm is extruded at a

A long aluminum wire of diameter 3 mm is extruded at a temperature of 280°C. The wire is subjected to cross airflow at 20°C at a velocity of 6 m/s. Determine the rate of heat tra...

Q: A manufacturer makes absorber plates that are 1.2 m ×

A manufacturer makes absorber plates that are 1.2 m × 0.8 m in size for use in solar collectors. The back side of the plate is heavily insulated, while its front surface is coated with bl...

Q: Consider a person who is trying to keep cool on a hot

Consider a person who is trying to keep cool on a hot summer day by turning a fan on and exposing his entire body to airflow. The air temperature is 85°F, and the fan is blowing air at a ve...

Q: Repeat Prob. 20–32 for an aluminum plate painted flat

Repeat Prob. 20–32 for an aluminum plate painted flat black (solar absorptivity 0.98 and emissivity 0.98) and also for a plate painted white (solar absorptivity 0.26 and emissivity 0...