What is true about the characteristics of steady flow systems? Select all that apply.  A.) There is neither accumulation or diminution of mass within the system   B.) The state of the working substance at any point in the system remain constant   C.) There is neither accumulation or diminution of energy within the system

2. A heat pump is like a refrigerator in that it uses work to take heat from a cold source (Tc, the inside of a house) and dumps it into a hot source (Th, usually the outdoor environment). a) Use the second law to find the magnitude of the work |w| needed to extract |qc] from the cold source and dump into the hot source. b) Assume all processes are reversible and the second law to explain why |w| > 0 if lgc] > 0 in part a).

The manufacturer of the device claims that it accepts a heat transfer at a rate of QH = 3.0 kW from a low-grade source of geothermal heat at TH = 80ºC and rejects heat at rate QC to the atmosphere at TC = 20ºC. The device operates at steady state and produced work at a rate of W= 2.5 kW. There are no other heat or work transfers from the device. a.) What is the rate at which the device rejects heat to the atmosphere, QC ? b.) Is this device possible? Justify your answer using an entropy balance.

5. (Pp133p-ex4.4-jrfra) - A closed system executes a series of processes for which two of the three quantities, W, Q, and AU are given for each process. Find the value of the unknown quantity in each case. a) W = 10 Hp, Q = 500 Btu/min, AU = ? b) W = ?, Q = 5 Btu, AU = 4.22 kJ c) W = 65 Btu, Q = ?, AU = -25 Btu d) W = 1,200, Q = 645 kJ e) W = -389 ft-lb, Q = -1.5 Btu, AU = ?

Water undergoes two processes in series: • 1 to 2: isentropic (internally reversible and adiabatic) compression from 0.1 MPa and the phase of water is “saturated vapor” to 0.5 MPa• 2 to 3: a reversible isothermal process to 1.5 MPaa) Draw the overall process on a T-s diagram. Clearly indicate all states and the values of the relevant intensive properties on your diagram. b) Is process 2 to 3 a compression, expansion, or isochoric process? How do you know? c) Determine the overall specific work (w13) and specific heat transfer (q13) for this complete process. (Hint: recall that Q int rev =∫ T ds21 for an internally reversible process between states 1 and 2.)

b) A tank shown in Figure-2 below is used to mix methanol and salt. The tank initially contains 1 m³ of methanol. Salt is provided into the tank with a volumetric flow rate of Fsalt= 0.2 m³ s¹. A stream with perfectly mixed methanol and salt leaves the tank with a volumetric flow rate of F = 0.1 m³ s1. As the flow is unsteady, the volume of mixture in the tank, V(t), is a function of time. Fsalt=0.2 m³/s Psalt=2160 kg/m³ V(t) F=0.1 m³/s Figure-2: A mixing tank of methanol and salt. d(V (t)Psalt) dt Salt+methanol The mass balance of salt in the tank is given by, d(V (t) (Psalt +Pmethanol)) dt = Fsalt Psalt - FPsalt where Psalt is the density of salt and equal to 2160 kgm ³. The total mass in the tank is given by, = Fsalt Psalt - FPsalt - FPmethanol where Pmethanol is the density of methanol and equal to 800 kgm-³. When the tank contains V = 0.5m³ of mixture, what is the mass of salt in the tank? Use the explicit Euler finite difference method to discretise the balance equations. (Hint:…

An air pump is used to fill a rigid gas bottle with air. The pump is connected to the gas bottle via a rigid pipe. The pump consists of a piston of internal diameter d=0.08 m and a cylinder with a stroke L=0.3m. Air enters the pump through an orifice located at the bottom of the cylinder to raise the pressure in the pump to atmospheric pressure. Air, drawn into the pump through the orifice, mixes completely and adiabatically with the cylinder contents. A valve allows the bottle's refill. The valve opens when the pump pressure is equal to the gas bottle. The valve is always closed when the pump pressure is below the gas bottle pressure. Pressure drop across the valve can be neglected. The bottle, the connecting pipe and the pump are thermally insulated. Air in the pump and connecting pipe undergoes isentropic compression and expansion processes. I F-one The working fluid (air) can be considered a perfect gas with R=287 J/KgK, cp=1005 J/KgK and y=1.4. Initially the piston is located at…

A power cycle consisting of the three processes: Process 1-2: Constant volume to P2 Process 2-3: Polytropic expansion Pv=c, use k=1.28 Process 3-1: Compression at constant pressure Assuming 2.5 kg carbon dioxide as the working substance with P₁= 1.5 bar, P₂= 6 bar, T₁=350 K and neglecting kinetic and potential energy effects: a) sketch cycle in P-v diagram b) calculate thermal efficiency CO₂ molar mass = 44. CO₂ specific heat cy=1.014 kJ/kg/K