The frictionless piston pictured below is free to move between the stops shown in the figure. When the piston rests on the lower stops, the enclosed volume is 0.4 mĀ³. When the piston reaches the upper stops, the enclosed volume is 0.6 mĀ³. Due to its weight, the piston moves when pressure in the enclosed volume is at 300 kPa. Initially, the cylinder contains 1.179 kg of water at 100 kPa. Heat is applied until all water exists as saturated vapor. Hint 1: The piston will reach the upper stops before all water becomes saturated vapour (final state). Hint 2: It might be easier to think about the intermediate states, but it's not necessary. a) Determine final pressure (kPa), specific volume (mĀ³/kg), and specific internal energy (kJ/kg) of the end state. Hint: For part a), DO NOT interpolate - find the closest tabulated value and use it. (6 points) b) Sketch the P-v diagram for the entire process. (8 points) c) Find the work done (kJ) by piston for the entire process. (6 points) d) Find the heat transfer (kJ) for the entire process. (8 points) mH2O = 1.179kg
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We can use a steam table to find the properties of water at this state. From the table, we find that the specific volume of saturated vapor at 300 kPa is 0.194 m/kg and the specific internal energy is 2,717.5 kJ/kg. Show moreā¦
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A two-phase liquid-vapor mixture of $\mathrm{H}_{2} \mathrm{O}$ with an initial quality of $25 \%$ is contained in a piston-cylinder assembly as shown in Fig. P3.40. The mass of the piston is $40 \mathrm{~kg}$, and its diameter is $10 \mathrm{~cm}$. The atmospheric pressure of the surroundings is 1 bar. The initial and final positions of the piston are shown on the diagram. As the water is heated, the pressure inside the cylinder remains constant until the piston hits the stops. Heat transfer to the water continues until its pressure is 3 bar. Friction between the piston and the cylinder wall is negligible. Determine the total amount of heat transfer, in J. Let $g=9.81 \mathrm{~m} / \mathrm{s}^{2}$
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A mass of $3 \mathrm{~kg}$ of saturated liquid-vapor mixture of water is contained in a piston-cylinder device at $160 \mathrm{kPa}$. Initially, $1 \mathrm{~kg}$ of the water is in the liquid phase and the rest is in the vapor phase. Heat is now transferred to the water, and the piston, which is resting on a set of stops, starts moving when the pressure inside reaches $500 \mathrm{kPa} .$ Heat transfer continues until the total volume increases by 20 percent. Determine $(a)$ the initial and final temperatures, $(b)$ the mass of liquid water when the piston first starts moving, and $(c)$ the work done during this process. Also, show the process on a $P$ - $\cup$ diagram.
A vertical piston-cylinder assembly contains 0.5 kg of unidentified substance: take the unidentified substance to be the system initially. The piston is resting against the stops when the system pressure and temperature are 4.00 bar and 0ĆĀ°C, respectively. The piston has a mass of 75 kg and a face area of 0.184 m^2. The local atmospheric pressure is 1.01 bar and the local gravitational acceleration is 9.81 m/s^2. What system pressure would be required to lift the piston from the stops? (2) Thinking about the substance as the system: is the system best described as open, closed, or isolated? Why? (3) Are changes in kinetic and potential energy negligible for the system in this case? Why? (4) How much heat transfer must occur to the system in order to begin to lift the piston from the stops? Once the piston is lifted from the stops, will the system pressure change? Why? (6) Assuming that the system's pressure remains constant, find the work in kJ for the volume to increase by 15% (V_final = 1.15 * V_initial). Carefully indicate the direction (i.e., what is the work that you reported being done on or by?). Suppose the heat transfer stops and the substance is allowed to come to an equilibrium temperature with its environment at 25ĆĀ°C. What phase(s) will the substance be?
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