A particular lake has been isolated and unchanged for more t…
A particular lake has been isolated and unchanged for more than a thousand years. One day a company buys the property the lake is on and tries to turn the lake into a self-sustaining fish farm. Unfortunately, there just aren’t enough nutrients in this lake to support a self-sustaining ecosystem capable of producing large fish so the company goes out of business. How would you describe this lake’s water quality?
Read DetailsA rigid copper tank, initially containing 2 m^3 of nitrogen…
A rigid copper tank, initially containing 2 m^3 of nitrogen at 300 K, 1 bar, is connected by a valve to a large supply line carrying nitrogen at 300 K, 20 bar. The valve is opened only as long as required to fill the tank with nitrogen to a pressure of 20 bar. Finally, the nitrogen in the tank is at 310 K. The copper tank, which has a mass of 10 kg, is at the same temperature of the air in the tank, initially and finally. The specific heat of copper is c = 0.385 kJ/kg/K. (a) Assuming ideal gas behavior of the nitrogen, determine the initial mass of nitrogen in the tank, in kg. m_1 = _______ kg. (b) Determine the final mass. m_2 = _______ kg. (c) Find the heat transfer to the surroundings from teh tank and its contents, in kJ, ignoring kinetic and potential energy effects. _______ kJ.
Read DetailsAn air compressor provides 6700 kW to raise air from an inle…
An air compressor provides 6700 kW to raise air from an inlet temperature T_1 = 300 K and inlet pressure p_1 = 1 bar to an outlet pressure T_2 = 620 K and outlet pressure p_2 = 12 bar. (a) What is the mass flow rate of air through the compressor, in kg/s? _______ kg/s. The air leaving the compressor flows through a regenerator, where it exchanges heat with a second air stream. The stream leaving the compressor leaves the regenerator at T_3 = 760 K and p_3 = 12 bar. The second air stream enters the regenerator at T_4 = 780 K and p_4 = 1 bar. Its mass flow rate, m_dot_4, is double the mass flow rate of the stream flowing through the compressor. (b) Find the temperature, T_5. Use linear interpolation to obtain an answer that is accurate to 0.1 K. _______ K.
Read DetailsA direct contact heat exchanger (mixer) operates at a fixed…
A direct contact heat exchanger (mixer) operates at a fixed pressure of p = p_1 = p_2 = p_3 = 25 bar with a working fluid of water. One stream of water enters at T_1 = 35 deg C and pressure p_1 = 25 bar. A second stream enters at p_2 = 25 bar and a quality x_2 = 0.50. The well-mixed streams leave as a saturated liquid at p_3 = 25 bar. Find the mass flow rate of stream 2. m_dot_2 = _______ kg/s.
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