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Applying the Entropy Balance: Closed SystemsA 50-lb iron
Chapter 6, Problem 63P(choose chapter or problem)
A 50-lb iron casting, initially at \(700^{\circ} \mathrm{F}\), is quenched in a tank filled with 2121 lb of oil, initially at \(80^{\circ} \mathrm{F}\). The iron casting and oil can be modeled as incompressible with specific heats \(0.10 \mathrm{Btu} / \mathrm{lb} \cdot{ }^{\circ} \mathrm{R}\), and \(0.45 \mathrm{Btu} / \mathrm{lb} \cdot{ }^{\circ} \mathrm{R}\), respectively. For the iron casting and oil as the system, determine (a) the final equilibrium temperature, in \({ }^{\circ} \mathrm{F}\), and (b) the amount of entropy produced within the tank, in \(\mathrm{Btu} /{ }^{\circ} \mathrm{R}\). Ignore heat transfer between the system and its surroundings.
Questions & Answers
QUESTION:
A 50-lb iron casting, initially at \(700^{\circ} \mathrm{F}\), is quenched in a tank filled with 2121 lb of oil, initially at \(80^{\circ} \mathrm{F}\). The iron casting and oil can be modeled as incompressible with specific heats \(0.10 \mathrm{Btu} / \mathrm{lb} \cdot{ }^{\circ} \mathrm{R}\), and \(0.45 \mathrm{Btu} / \mathrm{lb} \cdot{ }^{\circ} \mathrm{R}\), respectively. For the iron casting and oil as the system, determine (a) the final equilibrium temperature, in \({ }^{\circ} \mathrm{F}\), and (b) the amount of entropy produced within the tank, in \(\mathrm{Btu} /{ }^{\circ} \mathrm{R}\). Ignore heat transfer between the system and its surroundings.
ANSWER:Solution 63P
Step 1 of 5
Here, an iron casting is subjected to quenching process in an oil tank. The initial temperatures, mass and specific heats of iron casting and oil are given. We need to find the final equilibrium temperature and amount of entropy produced within the tank.