A steam generator consists of a bank of stainless stell (k=15 W/m·K) tubes habing the core configuration of CF7.0-5/8J and an inner diameter of 13.8 mm. The tubes are installed in a plenum whose square cross section is 0.6 m on a side, thereby providing a frontal area of 0.36 m². Combustion gases whose propertires may be aproximated as those of atmospheric air, enter the plenum at 900 k and pass in cross flow over the tubes at 3 kg/s. There are 11 rows of tubes in the gas flow direction. If saturated water at 2.455 bar experiences boiling in the tubes, what is the gas exit temperature? A convection coeficient of 10.000 W/m²·K is associated with boiling in the tubes.

13.0 (20 pts) An electroplating process will be used to coat the exterior surface of a 160 mm diameter x 1.5 meter long cylinder with silver. Determine the time in minutes to electroplate silver to a thickness of 0.06 mm if the plating current is 15 amps.

A system that operates in a reversible cycle receives energy by heat transfer from a 15.7oC reservoir at a rate of 26.9 kW, and delivers energy by heat transfer to a 49.8oC reservoir. Determine the rate of heat transfer (kW) to the high temperature reservoir.

An insulated tank containing 0.5m3 of R-134 at 500 kPa and 90% quality is connected to an initially evacuated insulated piston-cylinder device. The force balance on the piston is such that a pressure of 120kPa is required to lift the piston. The valve is then opened slightly and part of the refrigerant flows to the cylinder, pushing the piston up and the final cylinder volume is 1.5 m 3 . The process ends when the pressure in the tank drops to 120kPa. Assume the refrigerant in the tank undergoes an isentropic process. (a) Determine the quality in the tank and the cylinder. 0.896, 0.92 (b) Calculate the boundary work 280.8 kJ (Expansion) (c) Determine the entropy generated during the process 0.1973 kJ/K

Metal hydrides are metal alloys that can store significant quantities of hydrogen in their atomic lattice. For this reason, they are considered potentially attractive for the on-board storage of hydrogen for hydrogen fuel cell vehicles. A certain metal hydride alloy can store 2 wt% hydrogen and has a density (including the hydrogen) of 12 g?cm3. Treating hydrogen as an ideal gas, what pressure would beneeded tocompressgaseous hydrogen tothesameequivalent concentration thatit attains when absorbed in the metal hydride?

a. Why are commercial or any aircraft that fly at altitude, pressurized?

b. What is Pascal’s pressure assumption?

c. What are typical pressures used within commercial aircraft?

d. Explain air pressure and why it is higher at sea level than at high altitudes, support with diagrams if needed. (Hint, in a room is the cold air, it is at the floor. Is its density greater than hot air?)

A gas turbine operates as a cold-air standard Brayton cycle. Air enetrs the compressor at 300K and 100kPa and is compressed to 700kPa. During the heat addition process in the combustor, the temperature of the air increases to 1000K. The turbine and compressor can be assumed to be operating isentropically. Evaluate specific heat at 300K.

a. thermal efficiency of the cycle?

b. net work of the cycle (kj/kg)?

c. Back work ratio?

A counter-flow double-pipe heat exchanger is heating water from 20 to 80 C at a rate of 1.2 kg/s. The heating is provided by water at 160 C and a rate of 2 kg/s. The inner tube has a diameter of 1.5 cm, and the U is 640 W/m2 K. Use the effectiveness-NTU method to determine the length of the heat exchanger required.

List the Social and Economic issues of with respect to power plant

Derive the Friction Hill equation for open die forging of a cylindrical workpiece

How carbon affect hardness?? and Discuss the hardenability of each material.

1018 steel, 4140 steel, 1045 steel and 8620 steel

A new semi-automatic machine costs $ 80,000 and is expected to generate revenues of $ 40,000 per year for 6 years. It will cost $ 25,000 per year to operate the machine. At the end of 6 years, the machine will have a salvage value of $ 10,000. Evaluate the investment in this machine using all four methods (payback period, present worth, uniform annual cost (UAC), and rate of return). Neglect the salvage value for the payback period method and the rate of return methods.

Suppose, a completely automated machine is available for $ 140,000. The annual operating cost is $ 10,000 and the service life is expected to be 7 years. The salvage value of this equipment at the end of this period is $ 25,000. Revenues from this alternative too are $ 50,000 per year. Use the UAC method to compare this investment alternative with the semi-automatic machine investment.

Use a rate of return of 15 % where necessary.

Beer is to be pumped from a fermenting vessel to a racking tank at a velocity of 1.5 m/s through a 100 mm ID pipe, having an absolute roughness of 0.05 mm. The total length of the pipe, allowed for fitting and valves is equivalent to 10 m on the suction side of the pump and 60 m on the delivery. The pump is situated at 3 m below the constant level of beer in the fermenting vessel, which is at atmospheric pressure. Beer is discharged at the level 15 m above the pump in the racking tank. The pressure at the delivery point is 200kPa. The pump efficiency is 60%.

Make appropriate assumption and calculate the total head to be developed by the pump, its size and its required NPSH.

Given: beer viscosity = 0.001 Pa.s, beer density = 1.010 kg/l, vapour pressure = 2.3 kPa

A 20 degree Brix apple juice is being pumped from an open tank through a 1-in nominal diameter sanitary pipe into a second tank at a higher level. The mass flow rate is 1 kg/s through 30 m of straight pipe with two 90 degree standard elbows and one angle valve. The supply tank maintains a liquid level of 3 m and the apple juice leaves the system at an elevation of 12 m above the floor. Compute the power requirements of the pump.

Given: Juice density is 997.1 kg/m3 and viscosity is 2.1*10-3 Pa.s. Pump efficiency is 60%.

Air is compressed from 100 Kpa and 22 C to an outlet pressure 8 times greater. The compressor is not well insulated and loses heat at a rate of 120 kJ/kg. It is also note that there is a decrease in the entropy of the air of 0.4 kJ/kg-K between the inlet & the outlet. Assuming constant specific heats determine a) The outlet air temperature b) The required work input (kJ/kg) c) The entropy generation sgen (kJ/kg-K) during the compression process