Q: In a thermal system, water enters a 25-mm-
In a thermal system, water enters a 25-mm-diameter and 23-m-long circular tube with a mass flow rate of 0.1 kg/s at 25°C. The heat transfer from the tube surface to the water can be expressed in terms...
See AnswerQ: The upper and lower compartments of a well-insulated container are
The upper and lower compartments of a well-insulated container are separated by two parallel sheets of glass with an airspace between them. One of the compartments is to be filled with a hot fluid and...
See AnswerQ: Consider a 10-m-long smooth rectangular tube, with
Consider a 10-m-long smooth rectangular tube, with a = 50 mm and b = 25 mm, that is maintained at a constant surface temperature. Liquid water enters the tube at 20°C with a mass flow rate...
See AnswerQ: Someone claims that the airspace in a double-pane window enhances
Someone claims that the airspace in a double-pane window enhances the heat transfer from a house because of the natural convection currents that occur in the airspace and recommends that the double-pa...
See AnswerQ: A computer cooled by a fan contains eight printed circuit boards (
A computer cooled by a fan contains eight printed circuit boards (PCBs), each dissipating 12 W of power. The height of the PCBs is 12 cm and the length is 15 cm. The clearance between the tips of the...
See AnswerQ: Consider a double-pane window consisting of two glass sheets separated
Consider a double-pane window consisting of two glass sheets separated by a 1-cm-wide airspace. Someone suggests inserting a thin vinyl sheet between the two glass sheets to form two 0.5-cm wide compa...
See AnswerQ: In a manufacturing plant that produces cosmetic products, glycerin is being
In a manufacturing plant that produces cosmetic products, glycerin is being heated by flowing through a 25-mm diameter and 10-m-long tube. With a mass flow rate of 0.5 kg/s, the flow of glycerin enter...
See AnswerQ: What does the effective conductivity of an enclosure represent? How is
What does the effective conductivity of an enclosure represent? How is the ratio of the effective conductivity to thermal conductivity related to the Nusselt number?
See AnswerQ: Liquid glycerin is flowing through a 25-mm-diameter and
Liquid glycerin is flowing through a 25-mm-diameter and 10-m-long tube. The liquid glycerin enters the tube at 20°C with a mass flow rate of 0.5 kg/s. If the outlet mean temperature is 40°C and the tu...
See AnswerQ: A rigid tank with a volume of 0.117 m3 contains
A rigid tank with a volume of 0.117 m3 contains 1 kg of refrigerant-134a vapor at 240 kPa. The refrigerant is now allowed to cool. Determine the pressure when the refrigerant first starts condensing....
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