Questions from Principles Of Heat Transfer

Q: Water at 180°C enters a bare, 15-m

Water at 180°C enters a bare, 15-m-long, 2.5-cm-diameter wrought iron pipe at 3 m/s. If air at 10°C flows perpendicular to the pipe at 12 m/s, determine the outlet temperature of the water. (Note that...

Q: The temperature of air flowing through a 25-cm- diameter

The temperature of air flowing through a 25-cm- diameter duct whose inner walls are at 320°C is to be measured using a thermocouple soldered in a cylindrical steel well of 1.2-cm OD with an...

Q: Develop an expression for the ratio of the rate of heat transfer

Develop an expression for the ratio of the rate of heat transfer to water at 40°C from a thin flat strip of width D/2 and length L at zero angle of attack and from a tube of the same length and dia...

Q: Repeat Problem 6.17 for air flowing over the same two

Repeat Problem 6.17 for air flowing over the same two surfaces in the Reynolds number range between 40,000 and 200,000. Neglect radiation.

Q: The instruction manual for a hot-wire anemometer states that “

The instruction manual for a hot-wire anemometer states that “roughly speaking, the current varies as the one-fourth power of the average velocity at a fixed wire resistance.” Check this statement,...

Q: A mercury-in-glass thermometer at 40°C (

A mercury-in-glass thermometer at 40°C (OD = 1 cm) is inserted through a duct wall into a 3 m/s airstream at 66°C. This can be modelled as a cylinder in cross-flow, as shown...

Q: Wearing layers of clothing in cold weather is often recommended because dead

Wearing layers of clothing in cold weather is often recommended because dead-air spaces between the layers keep the body warm. The explanation for this is that the heat loss from the body is less. Com...

Q: A hot-wire anemometer is used to determine the boundary layer

A hot-wire anemometer is used to determine the boundary layer velocity profile in the air flow over a scale model of an automobile. The hot wire is held in a traversing mechanism that moves the wire i...

Q: A platinum hot-wire anemometer operated in the constant-temperature

A platinum hot-wire anemometer operated in the constant-temperature mode has been used to mea- sure the velocity of a helium stream. The wire diameter is 20 m, its length is 5 mm, and it is operated...

Q: A hot-wire anemometer consists of a 5-mm-

A hot-wire anemometer consists of a 5-mm-long, 5-mm-diameter platinum wire. The probe is operated at a constant current of 0.03 A. The electrical resistivity of platinum is 17 / cm at 20°C and increas...