8. A Piper Cherokee is flying at 4000 ft standard altitude at 105 mph. The wing has a rectangular planform (shape) with a span of 30 ft and a chord of 5.33 ft. Assuming that the turbulent boundary layer grows as on a smooth plate and a completely turbulent boundary layer flow, determine: (a) The boundary layer thickness at the downstream edge of the wing. (b) The total skin friction drag coefficient of the wing. (c) The total skin friction drag of the wing in pounds.

9. Repeat the analysis for Prob. 8 assuming that the boundary layer is laminar.

Consider a high-speed subsonic wind tunnel. The conditions in the large-diameter section upstream of the test section are V = 228 mph and T = 540°R. At the test section, the temperature is 473°R and the pressure is 2 atm. (a) If a wind tunnel model, placed in the test section, has a wing chord of 12 in., what is the test Reynolds number based on that chord? (b) What is the overall smooth flat-plate skin friction coefficient of the model wing if the boundary later is turbulent? (c) Determine the boundary layer thickness at the trailing edge of the model wing. (d) Calculate the skin friction drag in pounds for a model with a span of 3 ft.

Assume that we wish to design a Mach 10 hypersonic wind tunnel using air as the test medium. We want the static pressure and temperature in the test stream to be that for a standard altitude of 55 km. Calculate (a) the exit-to-throat area ratio, (b) the required reservoir pressure (in atm), (c) the required reservoir temperature, and (d) the exit velocity. What do these results tell you about the special (and sometimes severe) operating requirements for a hypersonic wind tunnel?

On October 3, 1967, test pilot William “Pete” Knight flew the X-15 hypersonic research vehicle to a world’s speed record for an airplane; he achieved Mach 6.7 at an altitude of 102,100 ft. (a) What was the maximum velocity in ft/s? (b) What was the flow temperature at the nose of the vehicle? Assume standard altitude

Water vapor enters a turbine operating at steady state at 480°C, 90 bar, with a velocity of 247 m/s, and expands adiabatically to the exit, where it is saturated vapor at 12 bar, with a velocity of 113 m/s. The exit diameter is 0.22 m. Determine the power developed by the turbine, in kW.

14. Sacrificial anodes are bolted inside the_____ of a heat exchanger

15. Sacrificial anodes minimize______ within a heat exchanger

17. The two factors that determine the choice of tools and equipment for a specific heat exchanger
of a heat exchanger maintenance job are familiarity with the (a)________ and knowledge of the (b)______

18. Blockage in a shell-and-tube heat exchanger may range from relatively light accumulations of (a)_______ and (b)_______ to heavy blockage caused by (c)_______ in cooling water

22. Automatic cleaning systems work by either (a)________or (b)_______ means

23. Some automatic chemical cleaning systems periodically introduce chlorine into the incoming water to kill________ and prevent growth on tube walls

25. When a main condenser is to be flooded, jack or supports may be necessary to________

26. Maintenance of smaller heat exchangers is approached differently from large heat exchangens because the smaller components are (a)______ and can be moved by (b)______

Compare the phase angle obtained from the free response and the phase angle obtained from the harmonic response in physical meaning and explain their importance.

Explain the advantages and disadvantages of the following four methods when calculating the harmonic response.

1. method of undetermined coefficients
2. a graphic method
3. complex number method
4. Laplace transformation

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.

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?

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.

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

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

Explain what you understand by the word configuration design?