Chapter 5, Problem 5.7CU

A closed system undergoes a thermodynamic cycle with three steps: process 1-2 (from state 1 to state 2), process 2-3 (from state 2 to state 3), process 3-1 (from state 3 to state 1). During process 1-2, the system internal energy increases by 20J, during process 3-1, the system internal energy decreases by 15J. What is the change of system internal energy in process 2-3? Enter the answer with the sign: + or - , but without units. For example, +27. Enter zero with no sign: 0.

Steam enters a turbine operating at steady state at 750°F and 450 lbf/in² and leaves as a saturated vapor at 0.8 lbf/in². The turbine develops 12,000 hp, and heat transfer from the turbine to the surroundings occurs at a rate of 2 x 106 Btu/h. Neglect kinetic and potential energy changes from inlet to exit. Determine the exit temperature, in °F, and the volumetric flow rate of the steam at the inlet, in ft³/s. Step 1 Determine the exit temperature, in °F. T₂ = i °F.

Steam enters a turbine operating at steady state at 750°F and 450 lbf/in² and leaves as a saturated vapor at 0.8 lbf/in². The turbine develops 12,000 hp, and heat transfer from the turbine to the surroundings occurs at a rate of 2 x 106 Btu/h. Neglect kinetic and potential energy changes from inlet to exit. Determine the exit temperature, in °F, and the volumetric flow rate of the steam at the inlet, in ft3/s. Step 1 Your answer is correct. Determine the exit temperature, in °F. T2 = 94.3 Hint Step 2 °F. Determine the volumetric flow rate of the steam at the inlet, in ft³/s. (AV) 1 = i ft³/s Attempts: 1 of 4 used

A divider separates 1 lb mass of carbon monoxide (CO) from a thermal reservoir at 150o F. the carbon monoxide, initially at 60o F  and 150 lbf/in2, expands isothermally to a final pressure of 10 lbf/in2 while receiving heat transfer through the divider from the reservoir. The carbon monoxide can be modeled as an ideal gas. (a) For the carbon monoxide as the system, evaluate the work and heat transfer, each in Btu and the amount of entropy produced, in Btu/oR. (b) Evaluate the entropy production, in Btu/oR, for an enlarged system that includesthe carbon monoxide and the divider, assuming the state of the divider remains unchanged. Compare with the entropy production of part (a) and comment on the difference.

Give the description of the following basic concepts of thermodynamics: System, closed systems, open systems, isolated systems, intrinsic and heat energy of a working fluid,

A working substance enters a thermodynamic steady flow system with the following conditions:P1 = 20 Psia; v1 = 11.7 ft3, u1=101.6 Btu/lb, V1=150 ft/sec. The working substance leaves the system with the following conditions: p2=25 psia, v2 = 10.3 ft3/lb u=149.0 Btu/lb and V2 = 500 ft/sec. Changes through the system are negligible and 10 Btu/lb transferred head is added to the fluid as it passes through the system. Determine the work done on or by the fluid in Btu/lb.

The net change in volume (a property) during a cycle is always zero.

Steam in a piston-cylinder assembly undergoes a polytropic process, with n = 2, from an initial state where V₁ = 4.38600 ft³, p₁ = 400 lbf/in², and u₁ = 1322.4 Btu/lb to a final state where u₂ = 1036.0 Btu/lb and v₂ = 3.393 ft³/lb. The mass of the steam is 2.5 lb. Changes in kinetic and potential energy can be neglected. Determine the change in volume, in ft3, the energy transfer by work, in Btu, and the energy transfer by heat, in Btu.

A closed system undergoes a thermodynamic cycle with three steps: process 1-2 (from state 1 to state 2), process 2-3 (from state 2 to state 3), process 3-1 (from state 3 to state 1). During process 1-2, the system received energy by heat transfer of 5J and did work of 10J. During process 2-3, the system was transferred energy from its surrounding by heat transfer of 25J and work was done on the system of 20J. During process 3-1, the system discharged 40J to its surrounding by heat transfer. What is the net work in this cycle? Enter the answer with the sign: + or - , but without units. For example, +27. Enter zero with no sign: 0.