Thermodynamics - water

P = 20 bar, T = 250 C, what is the specific volume? (choose the closest answer)

a)0.1085

b)0.15

c)0.1200

d)0.1308

T = 240 C, P = 2.5 bar, what is the specific internal energy?.

a)2713.1

b)2714

c)2717.2

d)2720

P = 20 bar, h = 2900 kJ/kg, what is the temperature?

a)250

b)240

c)280

d)300

Transient heat transfer

Leaking steam completely fills a room, pushing out all of the air. The steam is at atmospheric pressure. Because the mortar cement siding walls are initially cool, at a uniform temperature of 22C, the steam begins to condense on the walls. Find the rate of condensation per square meter of wall at (a) 10 s and (b) 30 s after the leak.

The wall is 10 cm thick, and you may assume that the other side of the wall, the side not in contact with the steam, is insulated. You may make the following simplifying assumptions:

• The convective heat transfer rate due to steam condensation is infinitely high and remains constant

• The effects of radiation are negligible.

Solve the following using expressions m & n. NOT actual numbers

A HydroCarbon Fuel C_mH_n is burned at atmospheric pressure with stoichiometric amount of air as the oxidizer. Determine the EXPRESSION of air fuel ratio, the mole fraction and the combustion products.

Manufacturing Technology

1. Glass
(a) melting point
(b) process in producing glass

Air flows over a 4 meter long flat plate at a velocity of 8 m/s. Using a spreadsheet, calculate the boundary layer thickness and wall shear stress at 0.1 meter intervals along the plate. Do not plot the wall shear stress at x=0. Use a transition Reynolds number of 5 x 10^5 . (You will need to calculate Rex at each location to determine if the laminar or turbulent correlations should be used.) Generate a spreadsheet table that includes columns for the x location, Reynolds number, boundary layer thickness, and wall shear stress. Also include the exact transition location in the x column. At the transition location, calculate both the laminar and turbulent correlations and include both values in your plot. (The solution will have a jump at the transition point.) Plot your results for the boundary layer thickness and wall shear stress on separate plots. Submit a copy of your EXCEL table and the plots you generated. Include a plot title and label the axes with the variable name and units. Use only lines, no symbols, to show your analytical solution.

Im designing a boat anchor winch that anchors a load of 1000 kg into the water when the boat is stationary with a wire line from the winch to the anchor, I came up with a spur gear design a pinion gear 1 and gear 2. Gears is made of carbon steel. For that application what is the correct motor to connect into the spur gear. How much horseower does gear 1 and gear 2 need to operate a 1000 kg load. You can estamate the rest of the variables.

The flight test data for a given airplane refer to a level‐flight maximum‐velocity run made at an altitude that simultaneously corresponded to a pressure altitude of 30,000ft and density altitude of 28,500ft. Calculate the temperature (in °F) of the air at the altitude at which the airplane was flying for the test.

The person’s mass, m= 68.1 kg, the unknown drag coefficient is, c , with units kg/s, and the local acceleration of gravity is g= 9.80 m/s2 . Our model for the person’s velocity vs time gave us a linear differential equation whose analytical solution was the following:
V(t) = g*m/c*[1-exp(-c/m*t)].

Your job is to find “c”. You need to use the MATLAB “help” documentation to find the nonlinear curve fitting function and syntax for how to use it. Hint you should use the documentation and example for “lsqcurvefit”.
Include in your program a plot of the experimental velocity data vs time and the calculated velocity vs time. The graph should have a title, x and y labeled axis, and a legend. It is likely your legend will not be placed in a good position. Use again the MATLAB “help” documentation to learn how to move it to the southeast corner inside your plot.

The following table is experimental data regarding our parachutist. We have a measured velocity versus time after the jump, but before the chute is opened:
Time t (sec)

Velocity, cm/s
0


1
1000
2

1630

3
2300
4

2750
5

3100

6
3560
7

3900

8
4150
9

4290

10
  
4500

11
4600
12

4550

13
4600
14

4900

15
5000

As an experienced engineer, suggest two (2) alternatives to reduce the electrical usage and cost for air ducting unit . The alternative suggested should comprise one (1) technical modification and one (1) human feature.

Why is it that heat pumps are rarely used in the UK to heat homes? However in a remote               region there may be reason to use such a system. What type of system might you       recommend and what would be the criterion to justify the heat pump as an alternative to a          simple oil boiler?

GIVE FULLY EXPLAINED AND TYPED ANSWER

You are the head of the engineering department in a certain company. your department has been allocated an annual budget of R2.6 million for this year. it is now towards the endof the financial year and your department has overspent by 25%. your senior manager wants you to justify why this is so. YOur task is to present a report showing all the expense of your department for the year and analyse them in a form of a Pareto analysis and a drill down analysis. in your analysis, ensure that you highlight the cause of your over expenditure, including the failure modes of the equipment. Justify ypur financial over spend with things that affect maintenance such as economic factors (macro and micro), poor workmanship from contractors, shift arrangements, poor quality spares, emergency work that had to be done etc. your report must include at least 3 internet sources and 3 textbook sources.

please include graphs for pareto and drill down analysis or onstructions on how to go about doing it

As a body is projected to a high altitude above the earths surface, the variation of the acceleration of gravity with respect to altitude y must be taken into account. Neglecting air resistance, this acceleration is determined from the formula a=−g0[R2/(R+y)2], where g0 = 9.81 m/s2 is the constant gravitational acceleration at sea level, R = 6356 km is the radius of the earth, and the positive direction is measured upward.

With what velocity does the particle strike the earth if it is released from rest at an altitude y0 = 750 km?

What is the most frequently failed (engineering) product that you have observed in your life? Be specific about your failed product. If you are given a chance to redesign and choose appropriate materials, how would you go about it?