Questions from Thermal Fluid Science

Q: The thermal resistance networks can also be used approximately for multidimensional problems

The thermal resistance networks can also be used approximately for multidimensional problems. For what kind of multidimensional problems will the thermal resistance approach give adequate results?

Q: A long copper rod of diameter 2.0 cm is initially

A long copper rod of diameter 2.0 cm is initially at a uniform temperature of 100°C. It is now exposed to an airstream at 20°C with a heat transfer coefficient of 200 W/m2⋅K. How long would it take fo...

Q: When plotting the thermal resistance network associated with a heat transfer problem

When plotting the thermal resistance network associated with a heat transfer problem, explain when two resistances are in series and when they are in parallel.

Q: What is lumped system analysis? When is it applicable?

What is lumped system analysis? When is it applicable?

Q: A 10-cm-thick wall is to be constructed with

A 10-cm-thick wall is to be constructed with 2.5-m-long wood studs (k = 0.11 W/m⋅K) that have a cross section of 10 cm × 10 cm. At some point the builder ran out of those studs and started using pairs...

Q: Water is pumped from a lower reservoir to a higher reservoir by

Water is pumped from a lower reservoir to a higher reservoir by a pump that provides 20 kW of shaft power. The free surface of the upper reservoir is 45 m higher than that of the lower reservoir. If t...

Q: Springs in automobile suspension systems are made of steel rods heated and

Springs in automobile suspension systems are made of steel rods heated and wound into coils while ductile. Consider steel rods (ρ = 7832 kg/m3, cp = 434 J/kg⋅K, and k = 63.9 W/m⋅K) with diameter of...

Q: Consider a 10-in × 12-in epoxy glass laminate

Consider a 10-in × 12-in epoxy glass laminate (k = 0.10 Btu/h⋅ft⋅°F) whose thickness is 0.05 in. In order to reduce the thermal resistance a...

Q: Steel rods (ρ = 7832 kg/m3, cp =

Steel rods (ρ = 7832 kg/m3, cp = 434 J/kg⋅K, and k = 63.9 W/m⋅K) are heated in a furnace to 850°C and then quenched in a water bath at 50°C for 40 s as part of a hardening process. The convection heat...

Q: Clothing made of several thin layers of fabric with trapped air in

Clothing made of several thin layers of fabric with trapped air in between, often called ski clothing, is commonly used in cold climates because it is light, fashionable, and a very effective thermal...