Q: Consider turbulent forced convection in a circular tube. Will the heat
Consider turbulent forced convection in a circular tube. Will the heat flux be higher near the inlet of the tube or near the exit? Why?
See AnswerQ: Thick fluids such as asphalt and waxes and the pipes in which
Thick fluids such as asphalt and waxes and the pipes in which they flow are often heated in order to reduce the viscosity of the fluids and thus to reduce the pumping costs. Consider the flow of such...
See AnswerQ: What does the logarithmic mean temperature difference represent for flow in a
What does the logarithmic mean temperature difference represent for flow in a tube whose surface temperature is constant? Why do we use the logarithmic mean temperature instead of the arithmetic mean...
See AnswerQ: Reconsider Prob. 20–45. To reduce the cost of
Reconsider Prob. 20–45. To reduce the cost of heating the pipe, it is proposed to insulate it with enough fiberglass insulation (k = 0.035 W/m⋅K) wrapped in aluminum foil (ε = 0.1) to cut down the hea...
See AnswerQ: When is heat transfer through a fluid conduction and when is it
When is heat transfer through a fluid conduction and when is it convection? For what case is the rate of heat transfer higher? How does the convection heat transfer coefficient differ from the thermal...
See AnswerQ: A propane tank is filled with a mixture of liquid and vapor
A propane tank is filled with a mixture of liquid and vapor propane. Can the contents of this tank be considered a pure substance? Explain.
See AnswerQ: A 3-mm-diameter and 12-m-long
A 3-mm-diameter and 12-m-long electric wire is tightly wrapped with a 1.5-mm-thick plastic cover whose thermal conductivity and emissivity are k = 0.20 W/m⋅K and ε = 0.9. Electrical measurements indic...
See AnswerQ: Consider fluid flow in a tube whose surface temperature remains constant.
Consider fluid flow in a tube whose surface temperature remains constant. What is the appropriate temperature difference for use in Newton’s law of cooling with an average heat transfer coefficient?
See AnswerQ: During a visit to a plastic sheeting plant, it was observed
During a visit to a plastic sheeting plant, it was observed that a 45-m-long section of a 2-in nominal (6.03-cm-outer-diameter) steam pipe extended from one end of the plant to the other with no insul...
See AnswerQ: What is the physical significance of the number of transfer units NTU
What is the physical significance of the number of transfer units NTU = hAs/mcp? What do small and large NTU values tell us about a heat transfer system?
See Answer
