A simple steam power cycle contains a turbine, condenser, pump and a boiler. If the turbine inlet pressure is 14 MPa and 600 °C, and the Condenser Inlet Pressure is 18 kPa, calculate the following:
Work as accurate as possible. For each correct answer you receive 1 Mark, thus 10 Maximum. Choose the most appropriate answer from the lists, and then continue with the chosen answer in order to have your calculations as accurate as possible.
In: Mechanical Engineering
A simple steam power cycle contains a turbine, condenser, pump and a boiler. If the turbine inlet pressure is 14.5 MPa and 550 °C, and the Condenser Inlet Pressure is 19 kPa, calculate the following:
Work as accurate as possible. For each correct answer you receive 1 Mark, thus 10 Maximum. Choose the most appropriate answer from the lists, and then continue with the chosen answer in order to have your calculations as accurate as possible.
In: Mechanical Engineering
A converging-diverging rocket nozzle is connected to a combustion chamber filled with gas at a total pressure of 1200 kPa and a total temperature of 2400 K. The design exit Mach number is 2.9 and the nozzle throat area is 50 cm2 . Assume the gas behaves as an ideal gas with k = 1.3 and a molecular weight of 24 kg/kmol. Determine (a) The back pressure necessary to induce the design Mach number at the nozzle exit. (b) The design exit area for isentropic supersonic flow. (c) The static pressure at the throat when the flow is choked. (d) The mass flow rate through the nozzle when the flow is choked.
In: Mechanical Engineering
6. a. Using a machine element , describe fatigue in engineering
materials . Why is fatigue loading more dangerous than normal
loading. As a design engineer, how can you prevent failure by
fatigue.
d. A building collapsed in a city last month. List all possible
reasons that could have caused the failure and how these could have
been prevented.
c. What is the effect of extreme temperatures (too low or too high) on the property of material ( yield strength, ductility, toughness, brittleness , fatique strength)
In: Mechanical Engineering
Q : It is desired to maintain the temperature of hospital room at 24 degree centigrade at all the time . The size of the room is 12x12 having 2 ton Air conditioner and 1200 watt heater.
A) discuss proper mechanism so that the temperature should not exceed 24 degree centigrade at any condition ( Hot or cold weather ).
B) suggest and draw a block diagram for temperature control system for hospital room
In: Mechanical Engineering
5 a. A hollow circular cylinder is made of cast iron and has an outside diameter of 120mm and inside diameter of 95mm. The length is 960mm. It is subjected to an axial tensile load of 160kN. Determine the normal stress and extension of the cylinder if the Modulus of elasticity is 230GPa.
b. A hollow bar of rectangular cross section has an external cross
section of 30cm by 55cm with a thickness of 10cm. It is subjected
to and internal pressure of 2.3MPa, bending force of 8kN acting
over a distance of 3m and a torsional load of 35kNm. Determine the
maximum tensile and shear stresses. Using a factor of safety of 6,
whatis the maximum allowable combined stress in the bar.
In: Mechanical Engineering
The theory of viscoelasticity is used to describe the behaviour
of materials in liquid phase.
a. Describe an industrial application where viscoelasticity
occurs.
b. Describe any two models of viscoelasticity
c. For each of the models, identify a real life engineering problem
where it is applied and describe this.
d. How can the knowledge be used in design applications for the
problem you identified
above.
e. What are the challenges in the use of the knowledge for solving
practical problems.
In: Mechanical Engineering
A wing designer comes up with two wing designs with different
efficiency factors for a highaltitude
reconnaissance aircraft. The aircraft flies in steady, level flight
at low subsonic cruise
speeds so that it can obtain better images of the ground
underneath. If the weight, engine
thrust, aircraft speed and altitude are fixed, and induced drag is
always the same fraction of
the total drag, derive a relationship between wing span and
efficiency factor.
In: Mechanical Engineering
A high carbon steel shaft is used in an engine and subjected to
different loads. In order to analyse the stress in the shaft,
consider a rectangular element within the material. This element is
subjected to compressive stress of 135 MPa and shear stress of
166MPa in the vertical direction. The compressive stress in the
horizontal direction is 176MPa with a shear stress of
115MPa.
d. What will be the difference in the analysis above if there is
an additional torsional load (T) and bending moment (M).
e. Show how you can use any theory of failure to design this
shaft.
f. What are the challenges of applying the theories of failure in
actual engineering practice and as a design engineer, how would you
deal with these challenges.
a. Sketch the state of stress on this element.
b. Determine the maximum and minimum normal and shear stresses and
their plane of orientation.
c. If the yield strength of the material is 350MPa, Poison’s ratio
is 0.32, and factor of safety is 5, determine the diameter of the
shaft to avoid failure.
In: Mechanical Engineering
A machine is out of order for major work. Define
controls
exercised in Maintenance Department required for its
Maintenance.
In: Mechanical Engineering
A high carbon steel shaft is used in an engine and subjected to
different loads. In order to analyse the stress in the shaft,
consider a rectangular element within the material. This element is
subjected to compressive stress of 135 MPa and shear stress of
166MPa in the vertical direction. The compressive stress in the
horizontal direction is 166MPa with a shear stress of 115MPa.
a. Sketch the state of stress on this element.
b. Determine the maximum and minimum normal and shear stresses and
their plane of orientation.
c. If the yield strength of the material is 350MPa, Poison’s ratio
is 0.32, and factor of safety is 5, determine the diameter of the
shaft to avoid failure.
In: Mechanical Engineering
System of external forces acting on a planar rigid
body will cause its motion in a certain
manner. Explain in general how Newton’s laws of motion are used to
describe this
relationship between external forces and the resulting motion. Draw
free-body and inertia-
force diagrams clearly to illustrate this relationship
(5 mark)
In: Mechanical Engineering
For the two-dimensional, incompressible, irrotational flow, examine the uniform flow and the double flow superposition (flow over the roller).
a) Flow function and velocity potential.
b) Velocity field.
c) Stopping points.
d) Roller surface.
e) Surface pressure distribution.
f) Tensile force on the circular cylinder.
g) Lifting force on the circular cylinder.
In: Mechanical Engineering
why self heating is a problem in RTD's and not in thermisters?
In: Mechanical Engineering
A walk –in cooler 3 m by 5 m by 3m High equipped with twelve 0.6 m by 0.6 m triple-glass doors is used for general purpose storage in a drive-in market (heavy usage). The walls are insulated with 50 mm of expanded cut cell polystyrene, and the cooler is to be maintained at 2°C. Compute the cooling load in kilowatts based on a 16-h operating time if the ambient temperature is 25°C.
In: Mechanical Engineering