Questions
Design a steam power cycle that can achieve a cycle thermal efficiency of at least 40%...

Design a steam power cycle that can achieve a cycle thermal efficiency of at least 40% under the conditions that all turbines have isentropic efficiencies of 80% and all pumps have isentropic efficiencies of 65%. Prepare an engineering report describing your design. Your design report must include, but is not limited to, the following:

1. Discussion of various cycles attempted to meet the goal as well as the positive and negative aspects of your design.

2. System figures and T-s diagrams with labeled states and temperature, pressure, enthalpy, and entropy information for your design.

3. Sample calculations.

In: Mechanical Engineering

Suppose you own some land next to a 50 MW wind farm located on Colorado’s Front...

Suppose you own some land next to a 50 MW wind farm located on Colorado’s Front Range. Your land has a fantastic cliff/ridgeline with an elevation difference of 250 m. Evaluate whether or not you can make money by building a pumped hydroelectric energy storage system on your land that interfaces with the wind farm. Your plan is to capture excess energy from the wind farm or buy energy from the wind farm when electricity prices are low and sell that energy back to the grid when electricity prices are high (assume that the utility that owns the grid will grant you a fair contract). You find that a good power rating for your storage system is 50% of the rated wind farm output, or 25 MW. Also your storage system should be able to generate electricity at rated power for 8 h.

a. Determine the flow rate and reservoir size needed to accomplish the required power output and energy capacity. Pumped hydroelectric plants generally run at 80%–90% generating efficiency, depending on the size of the machinery. Suggest a reasonable surface area and depth for your two reservoirs.

b. Assume it costs $500 per kW to install your turbomachinery and penstocks, plus $2 per cubic yard to build reservoirs. Calculate the initial capital cost of your pumped hydroelectric system.

c. Suppose you can buy energy from the wind farm at $0.035/kWh between the hours of 10:00 pm and 8:00 am to charge your storage and sell energy between 1:00 pm and 9:00 pm back to the grid at $0.1/kWh. Select a reasonable simple payback period that would motivate you to invest in energy storage. Calculate the maximum capital cost expenditure on your energy storage system that would allow this payback period.

d. Would you decide to build this energy storage system? Why or why not?

In: Mechanical Engineering

Water flows at 112°C through a steel pipe (k=90 W/m °C) which has a 6 cm...

Water flows at 112°C through a steel pipe (k=90 W/m °C) which has a 6 cm inside diameter and 8cm outside diameter. Such that, hi =346 W/m2 °C and ho =6.0 W/m2 °C. Surrounding air temperature is 20°C. To reduce heat loss to the surroundings the pipe is covered with an insulation insulation having the thickness of 4.0 mm and k=0,5W/m°C . Calculate;
a.    The heat loss by convection per unit length from the bare pipe (before insulation).
b.    The heat loss from the insulated pipe,
c. The critical radius. And discuss the result.

In: Mechanical Engineering

Consider a circular (cylindrical) pin fin attached to a flat plane with the following properties: k...

Consider a circular (cylindrical) pin fin attached to a flat plane with the following properties:

k = 237 W/mC (thermal conductivity)

L = 100mm (length)

r = 2mm (radius)

T_b = 80 C (temperature at fin base)

T_inf = 20 C (air temperature)

h = 12 W/m^2C (Convection Coefficient)

Find the following using the infinitely long and insulated (adiabatic) tip methods:

The temperature of the fin at a distance L/2

Heat transfer rate from the fin

Fin efficiency

Fin Effectiveness

Thermal Resistance

In: Mechanical Engineering

What are the various methods used for comparison during the evaluation of concept? Explain briefly.

What are the various methods used for comparison during the evaluation of concept? Explain briefly.

In: Mechanical Engineering

Explain what you understand by the word configuration design?

Explain what you understand by the word configuration design?

In: Mechanical Engineering

g)When at least 50% copper material is alloyed with ..............................., ……………. material is obtained h)Alloys with...

g)When at least 50% copper material is alloyed with ..............................., ……………. material is obtained

h)Alloys with the highest strength / weight ratio ……………… are used in prosthesis and implant production

i)…………… used in coating canned cans, it is also used in the production of …………… material in joining processes)

j)………….plastic materials that do not melt when exposed to heat are produced by the method of ……………………… ..….)

k)…………………………… is used in the production of gaskets and tires)

l)The ………………..strength of ……………… used in cutting tool manufacturing is greater than the tensile strength)

In: Mechanical Engineering

In your first assignment as a new engineer at a large jet engine manufacturer, you are...

In your first assignment as a new engineer at a large jet engine manufacturer, you are part of a team investigating a new generation of lightweight turbine engines for regional jet liners. In order to increase efficiencies and improve performance, lightweight materials with significant toughness are needed. However, the operating conditions include high temperatures and high stresses. Of the three categories of composites, which one would you select for further investigation in an engine inlet application where temperatures in the vicinity of 500°C are experienced?

1. polyethylene
2. metal matrix composite
3. iron-aluminide intermetallics
4. ceramic matrix composite
5. polymer matrix composite

In: Mechanical Engineering

What is torque wrench and why it is used in oil rigs

What is torque wrench and why it is used in oil rigs

In: Mechanical Engineering

Write real life application of HYDRAULIC PRESSURE CONTROL VALVE- REDUCING VALVE OPERATION

Write real life application of HYDRAULIC PRESSURE CONTROL VALVE- REDUCING VALVE OPERATION

In: Mechanical Engineering

The optical Tachometer a- Can the SIS optical tachometer be used to determine the direction of...

The optical Tachometer

a- Can the SIS optical tachometer be used to determine the direction of rotation?
b- If number of slots in the disc is changed what effect would this have on the results?
c- Discuss sensor characteristics as linearity, repeatability, accuracy and sensitivity.
d- What are the sources of errors in this experiment?

In: Mechanical Engineering

Shows a new process in which 0.0100 kg of methane (an ideal gas) is compressed from...

Shows a new process in which 0.0100 kg of methane (an ideal gas) is compressed from a pressure of 0.100 MPa and a temperature of 20.0 °C to a pressure of 10.0 MPa in a polytropic process with n = 1.35. Determine the moving boundary work required.

Determine the work required in Example 4.5 if the final pressure of the methane is 0.500 MPa.

If the work required in Example 4.5 is ?5.00 kJ, determine the final temperature and pressure of the methane.

If the gas used in Example 4.5 were air, determine the work required to compress it polytropically from 14.7 psia, 70.0°F to 150.°F with n = 1.33.

In: Mechanical Engineering

A counterflow, concentric tube heat exchanger used for engine cooling has been in service for an...

A counterflow, concentric tube heat exchanger used for engine cooling has been in service for an extended period of time. The heat transfer surface area of the exchanger is 5 m2, and the design value of the overall convection coefficient (without any fouling) is 38 W/m2K. During a test run, engine oil flowing at 0.1 kg/s is cooled from 110oC to 66oC by water supplied at a temperature of 25oC and a flow rate of 0.18 kg/s. Determine whether fouling has occurred during the service period. If so, calculate the fouling factor, Rf (m2K/W). Specific heat of engine oil is 2166 J/kgK, and water is 4178 J/kgK.

What is Rf = x 10-3 m2K/W?

In: Mechanical Engineering

Design a concentric tube heat exchanger (in co-current configuration) to heat 1000 cm3/ min of water...

Design a concentric tube heat exchanger (in co-current configuration) to heat 1000 cm3/ min of water from 30oC to 45oC flowing in the shell, using water at 65oC flowing in the tube. The heating water should not exit with temperature above 55oC. Choose a suitable range of inner pipe (copper material) diameters for heat exchanger, assume suitable inner tube thickness and outer tube diameter and show selection of parameters and dimensions for an optimum design.

In: Mechanical Engineering

Prob. 4-68 A piston–cylinder device contains 2.2 kg of nitrogen initially at 100 kPa and 25C....

Prob. 4-68 A piston–cylinder device contains 2.2 kg of nitrogen initially at 100 kPa and 25C. The nitrogen is now compressed slowly in a polytropic process during which PV^1.3 = constant until the volume is reduced by one-half. Determine the work done and the heat transfer for this process.

4–69    Reconsider Prob. 4–68. Using EES (or other) software,plot the process described in the problem on a P-V diagram, and investigate the effect of the poly- tropic exponent n on the boundary work and heat transfer. Let the polytropic exponent vary from 1.0 to 1.4. Plot the boundary work and the heat transfer versus the polytropic exponent, and discuss the results.

In: Mechanical Engineering