Q2 A single stage nozzled axial flow gas turbine operates with 1000 K total inlet temperature and 4.8 bar inlet total pressure with 12 kg/s mass flow rate. The axial velocity throughout the stage is constant at 220 m/s and the blade speed is 350 m/s. The nozzle exit and the rotor exit angles are 65° and 7° respectively. The static pressure at the exit of the stage is 2.5 bar. Assuming equal inlet and exit absolute flow velocities, determine: (i) relative flow angle at rotor inlet; (ii) relative velocity at stage inlet; (iii) relative flow angle at rotor exit; (iv) relative velocity at stage exit; (v) absolute flow velocity; (vi) degree of reaction; and (vii) specific power output of the turbine

An electric vehicle has the following parameter values:

m_v = 800kg

C_D =0.2

A_f = 2.2 m²

ρ = 1.18 kg/m

f r = 0.008 + 0.6×10^-6×v² (v: vehicle speed in m/s)

The vehicle is on level road. It accelerates from 0 to 100 km/h in 10s such that its velocity profile is given by v (t) =0.29055t² for 0 < t < 10s. (The mass factor is assumed unit)

a. Define the traction force expression F_t

b. Sketch F_t versus time

c. Define the instantaneous traction power expression

d. Calculate the energy consumed during the acceleration (0 < t < 10s)

e. Calculate the energy lost for non-conservative forces (wind and rolling resistance)

f. Find the change in kinetic energy and the change in tractive energy during acceleration.

The solid rod shown here has a radius of ?. If it is subjected to the force of ?? at B point, answer the following questions.

Use ??=700 ??; ???=11 ??; ???=15 ??; ???=8 ??; ?=0.7 ??

1. (a) Determine the internal loadings, T, M and V on the sectioned area; see the free body diagram (ii) (5 pts)
2. (b) Determine the shear stress developed by the shear force (V) at A point (5 pts)
3. (c) Determine the normal stress developed by the bending moment (M) at A point (5 pts)
4. (d) Determine the shear stress developed by the torque (T) at A point (5 pts)
5. (e) Determine the stress components at A, ??,?? (5 pts)

1. The thermal efficiency of a Rankine power cycle may be improved by i. Superheating the steam ii. Reheating the steam between high and lower pressure sections of the turbine iii. Regenerative Feedwater Heating iv. Insulating the turbine and decreasing the entropy production during the expansion process v. Incorporating a Rankine cycle power system as part of a cogeneration system a. Items i), ii), and iv) only b. Items i), iii), and v) only c. Items ii), iv) and v) only d. All of these e. None of these

2. The back work ratio is … a. The ratio of the compressor outlet to inlet pressure in a vapor compression power system. b. The ratio of the pump work (power) input divided by the turbine work (power) output in a Rankine cycle power system. c. The ratio of the inlet pressure to the outlet pressure in a steam turbine. d. The ratio of the inlet pressure to the outlet pressure in the feedwater pump system of a Rankine cycle power system.

3. For the Rankine cycle process where steam expands through the turbine, in a realistic process, the entropy at the exit is … a. Greater than the entropy at the inlet. b. Equal to the entropy at the inlet. c. Less than the entropy at the inlet. d. Has no relationship to the entropy at the inlet.   e. None of these answers is correct.

4. Regenerative feedwater heaters may be … a. Devices where natural gas is used to heat feedwater to prevent freezing under cold conditions.   b. Open devices where the steam and the water being heated are at the same pressure, c. Closed devices where the steam and the water being heated may be at different pressures and do not mix, d. Open or closed devices, where both have their advantages and applications. e. Devices where steam is diverted, passed back into the steam generator, and then sent back into the turbine.   f. None of the above.

5. With regenerative feedwater heating, a powerplant will not have more than one stage of feedwater pump (i.e., each feedwater pump will take in water at condenser pressure and deliver water at steam generator/turbine inlet pressure). a. True b. False

6. In a power plant, the heat rejected from the condenser … a. Is not a significant amount of heat, is rejected into the surroundings, and is not a concern.   b. Is a significant amount of heat and is captured to turn the main turbine.   c. Is a significant amount of heat, is rejected into the surroundings, and can change the local environment. d. Heat is not rejected in the condenser.

7. Deaeration is needed in systems using water as a working fluid to remove air from the water and to minimize corrosion.   a. True b. False

8. A closed feedwater heater may be used for deaeration. a. True b. False
9. In a reciprocating power system,   i. Material flows at a constant rate through the device and passes through a turbine to produce shaft power output, ii. Material does not flow at a constant rate through every section of the device.   iii. Power is produced at all times. iv. Power is produced only during part of the cycle in each section of the device and is not produced uniformly at every instant.   v. The power unit consists of one or more piston and cylinder sections with intake and exhaust valves and where fresh fuel and air are taken in during one part of the process, exhaust gases are ejected during another part of the process, and at other times the cylinder is closed off from the intake and exhaust sections (manifolds).   vi. The power unit consists of a compressor, a burner section, and a turbine.   a. Items i), iii), and vi) are correct. b. Items ii) and iii) are correct. c. Items ii), iv) and v) are correct. d. Items ii), iv), and vi) are correct. e. None of these combinations are correct.

10. The Otto cycle model is used with … a. Reciprocating internal combustion engines where the fuel-air mixture is ignited by a spark. b. Reciprocating internal combustion engines where the fuel-air mixture is ignited by high pressures in the cylinders. c. Internal combustion engines with continuous flow of fuel and air (i.e., gas turbine engines). d. External combustion “hot air” engines. e. Vapor compression refrigeration.

11. In an air standard analysis, we pretend that the substance in an engine is pure air, and we analyze this as if energy is put into the air from the outside and, later, waste heat is removed from the air. a. True b. False

An extruded, rectangular polypropylene strut of width 9 mm, depth 3 mm and length 80 mm is to be loaded from the ends in compression along its length with a creep load of 40 N for one year. [Creep curves for polypropylene are shown below. The buckling load is given by F = (2 p/ L)2 E I. For a rectangular beam the second moment of area is given by I = (w d3) /12.].

In order to improve buckling resistance, explain with reference to the buckling equation, what changes are possible in either material or beam design, indicating any likely constraints on such changes.

Discuss the manufacturing problems (in terms of extruder system design) which must be considered in producing such a beam.

Explain “STANDARDS” and “CODES” by writing their basic characteristics (or essentials) and giving their similarities and differences (if any).

Give some case studies for Mechanical property assessment by nanoindentation technique.

A piston cylinder device with air is going through an isentropic compression. The initial pressure is 0.1 MPa and temperature is 300 K. During the isentropic compression process, the volume is decreased to 1/18 of the initial volume. Using variable specific heats, determine the pressure and temperature at the end of the compression process. What is the amount of work consumed?

Air flows in a converging-diverging nozzle. The nozzle throat area is 50 cm2. The total pressure at the nozzle inlet is 1 MPa. The total pressure at the nozzle exit is 650 kPa. The Mach number at the nozzle exit is 0.70. Find the nozzle exit area.

51.7 cm2

84.2 cm2

35.6 cm2

54.7 cm2

2. In the PLD method, among the mechanisms under which the material is ablated, I wonder what is the conditions for the exfoliation sputtering.

A proposed Ocean Thermal Energy Conversion (OTEC) plant draws heat from the ocean surface at 22°C and rejects heat to the water near the ocean bed at 4°C. What is the highest thermal efficiency the plant could achieve? [4] (b) Consider a system undergoing an adiabatic process from a fixed state 1 to a fixed state 2. Use the Second Law of Thermodynamics to prove that the maximum work is done by the system if the process is reversible. [6] (c) Steam at 20 MPa and 460°C flows at 12 kg/s into an adiabatic turbine and exits at 20 kPa. What is the maximum possible power output of the turbine? What is the temperature of the steam at the exit in that case? [5] (d) Steam at 20 MPa and 460°C flows at 12 kg/s into an adiabatic turbine and exits at 20 kPa and 85% quality. What is the isentropic efficiency of the turbine?

A one-stage rocket takes off from Space and is tasked with entering into a geosynchronous (the

period of orbit is one day) low earth orbit at an altitude of 2,000km above the surface of the Earth. The mass of the

rocket is 550,000kg,

a) At what final speed does the rocket need to be moving to achieve the specified orbit?

b) If the exhaust velocity of the fuel is 2.20x103m/s what percentage of the rocket’s mass must be fuel?

c) Given that the rocket expends fuel at a rate of 1.4x104kg/s would this rocket be appropriate for manned flights?

kindly do the stability analysis ( longitudnal, lateral stability) lift and moment coefficient for boeing 787 or boeing 777 aircraft.