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A piston cylinder arrangement shown in Figure is restrained by two linear springs asshown. The system contains air initially at a pressure of 150 kPa and a volume of 0.002 m3.Heat is added to the system until its volume doubles; determine the total work transfer. Alsosketch the process on P-V diagram. Both springs have spring constant of 100 kN/m.
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A piston cylinder device shown in Figure contains 0.1 kg of air initially at a pressure of4 MPa and temperature of 2000C. Heat is added to the system until the pressure is 8 MPa andthe temperature is 8000C. Sketch the process on P-V and T-V diagrams and determine thetotal work transfer. [Take R = 287 J/kg K
4
A gas is contained in a vertical, frictionless piston–cylinder device shown in Figure .The piston has a mass of 4 kg and a cross-sectional area of 35 cm2. A compressed springabove the piston exerts a force of 60 N on the piston. If the atmospheric pressure is 95 kPa,
determine the pressure inside the cylinder
5
Air contained within a vertical piston–cylinder assembly is shown in Figure . On itstop, the 10-kg piston is attached to a spring and exposed to an atmospheric pressure of 1 bar.
Initially, the bottom of the piston is at x = 0, and the spring exerts a negligible force on the
piston. The valve is opened and air enters the cylinder from the supply line, causing the4volume of the air within the cylinder to increase by 3.9 × 10-4 m3. The force exerted by the
spring as the air expands within the cylinder varies linearly with x according to Fspring = kx,
where k = 10,000 N/m. The piston face area is 7.8 × 10-3 m2. Ignoring friction between thepiston and the cylinder wall, determine the pressure of the air within the cylinder, when the
piston is in its initial position. Repeat when the piston is in its final position. The atmosphericpressure is 100 kPa and the local acceleration of gravity is 9.81 m/s2.
6
A container having two compartments contains steam as shown in fig The specific
volume of steam in compartment B is 5 m3/kg. The membrane breaks and the resulting
specific volume is 8 m3/kg. Find the original specific volume of steam in compartment A.
7
Given the conversion factor 1 inch H2O = 0.0361 psid and that the manometer below employs water, find the difference in pressure between compartments A and B.
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During a phase change, the specific entropy of a 20 lbm system increases from 0.31 − Btu lbm R to 1.61 − Btu lbm R while the temperature of the substance is a constant 212°F. Find the heat transfer into this system. Hint: Must convert temperature to Rankine.
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Steam enters a turboexpander as a saturated vapor at 500 psia and is expanded at constant entropy to 5 psia. Using the Mollier diagram in Appendix A (Figure A1), find the ?h for this process
10
. The following schematic of a simple Rankine cycle consists of steam leaving a boiler at T=550 F and P=400 psia and passes through a turboexpander where it does work and exhausts with an enthalpy of 932 Btu/lbm. The exhaust is then condensed to an enthalpy of 85 Btu/lbm before being pumped back into the boiler. h=932 Btu/lbm T=550 F P=400 psia h=?? Btu/lbm T 116 F h=85 Btu/lbm 6 7 turb boiler system Cond Btu Btu Given W = 4.15×10 and Q =1.43×10 ,find the mass flow rate of the lbm lbm system(m ), the total heat transfer out at the condenser(Q ),and the enthalpy of the fluid after leavin g the pump and before entering the boiler
11
What is the efficiency of a turbine which receives dry, saturated steam at 100 psia and exhausts a wet vapor at 1 psia, while producing 230 Btu/lbm of real work?
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What is the maximum possible cycle efficiency of a heat engine operating between a heat source at 400 F and a heat sink at 32 F?
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An inventor claims to have invented a device which absorbs 2500 Btu of heat and produces 2000 Btu of work. If the heat sink for the device is ice water (32 F), what would be the minimum source temperature?
14
A liquid compressed in cylinder has a volume of 0.04 m3 at 50 kg/cm² and a volume of 0.039 m3 at 150 kg/cm². The bulk modulus of elasticity of liquid is