Air expands through a turbine operating at steady state. At the inlet, p₁ = 150 lbf/in.², T₁ = 1400°R, and at the exit, p₂ = 14.8 lbf/in.², T₂ = 900°R. The mass flow rate of air entering the turbine is 11 lb/s, and 65,000 Btu/h of energy is rejected by heat transfer.

Neglecting kinetic and potential energy effects, determine the power developed, in hp.

Given the I/O equation
2ẏ + 10y = 3u(t) Sketch the response y(t) for a step input u(t) = 6U(t) and the initial condition y(0) = −2.

Using the Laplace Transform. Find the time constant to improve your sketch of the response.

Question 1 – Case Study (30%)
You are required to produce a written assignment of maximum 500 words for each section. Each section is 15 marks.
(a) The management of your company has requested you to propose two CAD
system for the new design project that was recently awarded to the company.
Your proposal should be a comparative study and include: -
i) CAD software name and developer
ii) Hardware and system requirements
iii) CAD/CAM features and capabilities
iv) Price
Based on the comparisons, given your recommendation on the suitable CAD system.
(b) Locate an engineering company (you may have visited as part of your work related learning) and produce your own case study of how the investment in CAD CAM has affected the business. You should produce an analysis of the investment and the impact on the output of the business. Identify also how they also may be planning to introduce additional machines as a result of the improvement in production.

100 people enter a room that is initially at a temperature of 15 C and pressure of 1bar. Each person losses heat to the air in the room at a constant rate of 300 W at a constant temperature of 37 C. The air mass in the room is 750 Kg, remains constant and its cv = 0.79 kJ/(Kg K), cp = 1.08 kJ/(Kg K) and the gas constant is 0.287 kJ/(Kg K). Air enters the room at a temperature 25 C at a mass flow rate of 0.01 Kg/s and leaves the room at the temperature of the room and at the same mass flow rate. The pressure remains constant during this process.

a) Determine the temperature of the air in the room after 30 minutes assuming that there is no heat transfer from the room to the surroundings because it is heavily insulated.

b) Calculate the entropy production for this process assuming that the people are at a temperature of 310 K.

A low-carbon steel plate is 270 mm wide and 25 mm thick. It is reduced in one pass in a two‑high rolling mill to a thickness of 20 mm. Roll radius = 300 mm, and roll speed = 30 m/min. Strength coefficient = 500 MPa, and strain hardening exponent = 0.25. Determine (a) roll force, N (b) roll torque, N-m and (c) power required to perform the operation kW.

A steel alloy specimen having a rectangular cross section of dimensions 19.1 mm × 3.0 mm (0.7520 in. × 0.1181 in.) has the stress-strain behavior shown in the Animated Figure 6.22. If this specimen is subjected to a tensile force of 95120 N (21380 lbf) then (a) Determine the amount of elastic strain induced. (b) Determine the amount of plastic strain induced. (c) If its original length is 590 mm, what will be its final length after this force is applied and then released? The elastic modulus for steel is 207 GPa.

Solve the following set of equations with LU factorization with pivoting:
3x1 -2x2 + x3 = -10
2x1 + 6x2- 4x3 = 44
-8x1 -2x2 + 5x3 = -26

Please show all steps

Aluminum fins of triangular profile are attached to a plane wall whose surface temperature is 100°C. The fin base thickness is 2.0 mm, and its length is 10 mm. The system is in ambient air at a temperature of 20°C, and the surface convection coefficient is 40 W/m2·K. (a) What are the fin efficiency and effectiveness? (b) What is the heat dissipated per unit width by a single fin?

(a)nf=

ef=

(b)q'f=

A brick wall 25cm thick, initially at 80°C has a medium at 15°C suddenly placed in conatct with both of its surfaces through a heat transfer coefficient of 90W/m2°C. Find the temperature at a point 2.5cm from the surafce after 10hrs have elapsed. Find also the heat that has flowed out of the wall during that time. Take ρ = 1602kg/m3, cp = 0.84kJ/kg°C, k = 0.69W/m°C,and α = 5.2×10-7m2/s.

The San Bruno pipeline explosion (the case in our first lecture) occurred at 6:11 pm PDT on September 9, 2010, in San Bruno, California, a suburb of San Francisco, when a 30-inch (76 cm) diameter steel natural gas pipeline owned by Pacific Gas & Electric (PG&E) exploded into flames in the Crestmoor residential neighborhood 2 mi (3.2 km) west of San Francisco International Airport near Skyline Boulevard and San Bruno Avenue.

“The (investigation) report concluded that poor pipeline welds went undetected because of a lack of inspections by the company and inadequate monitoring by state and federal regulators. The utility also lacked a workable emergency response plan that board members said could have helped to prevent the devastation in the city of San Bruno.”

"This represents a failure of the entire system — a system of checks and balances that should have prevented this disaster," said Robert L. Sumwalt, an NTSB board member. "The seam weld may have been the technical reason, but this was an organizational accident."

“Even though PG&E is a Local Distribution Company (LDC), a gas utility - and not primarily a midstream company - there were plenty of lessons to be learned by everyone, upstream, downstream, and all points in between. The investigation showed a myriad of events that led up to the catastrophe but a huge discovery was that PG&E and subsequently, many LDC's in the US, could not locate adequate records of their pipelines. Some did not even have emergency plans in place. Important records that were missing included type of pipe, when and where the line was installed, welding inspection reports, coating reports, in-line inspection histories, operating pressure changes, and more. All this data is critical to correctly operating and maintaining a steel pipeline. It was learned that some LDC's could not even locate some of their pipeline assets!”

Based on the above description and your knowledge about “Pipeline Integrity Management”, please :

1) identify the problems in the PG&E’s pipeline management from above description;

2) give your recommendations (at least FOUR items) to the PG&E to prevent similar failures happen again in the future.

Determine the rate of convection heat loss from both the top and the bottom of a flat plate at Ts = 80°C with air in parallel flow at T? = 25°C, u? = 3 m/s. The plate is t = 1 mm thick, L = 25 mm long, and w = 50 mm deep. Neglect the heat loss from the edges of the plate. Compare the rate of convection heat loss from the plate to the rate of convection heat loss from an Lc = 50­mm­long cylinder of the same volume as that of the plate. The convective conditions associated with the cylinder are the same as those associated with the plate.

ANSWER: 5.84 W, 3.73 W

Approximately spherical particles of diameter 150? and density 2650 kg/m3 settle through a liquid of density 1097 kg/m3 and dynamic viscosity 3.8 mPa s. The volume fraction of particles is 30% in a container of internal diameter 2 cm

Calculate: a)The absolute settling velocity that is apparent to the stationary observer in the lab frame. b)The slip velocity (Us) between solid and liquid phases. c) The superficial velocity of the particles in the lab frame.