4. A Rankine cylce operates between pressures of 2 psia and 1500
psia. If the steam entering the turbine is superheated to
800oF, calculate the efficiency of the cycle. Neglect
pump work. Note: The peak of the superheat phase
of this cycle is outside the range of the text steam tables and is
difficult to locate on the text Mollier chart since it does not
have a 1500 psia constant pressure line. Please use the following
information taken from the Combustion Engineering steam tables. At
1500 psia and 800 oF, the steam would have an h = 1364
Btu/lbm and an s = 1.5073 Btu/lbm oR. You should be able
to find the value of h at 2 psia and an s = 1.5073 Btu/lbm
oR from the text steam tables or the Mollier chart. Then
you can calculate the parameters requested by questions 4 and
5.
State your answer as a percent to one decimal place. Example:
35.2
5. A Rankine cycle operates between pressures of 2 psia and 1500
psia. If the steam entering the turbine is superheated to
800oF, calculate the work produced per pound mass of
steam. Neglect pump work.
State your answer to two decimal places. Example:125.25
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In: Mechanical Engineering
8. In a Rankine cycle steam enters the turbine at 900 psia and
1000oF and exhausts at 1 psia. What is the thermal
efficiency? Neglect pump work.
State your answer as a percent to one decimal place. Example:
25.2
9. Steam is expanded to 12% moisture at 1 psia in a Rankine
cycle. If the initial pressure is 400 psia, what is the efficiency?
Neglect pump work.
Express your answer as a percent to one decimal place. Example:
32.5
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In: Mechanical Engineering
An ideal diesel engine uses air as the working fluid and operates
with a thermal efficiency ?th =0.5 with a rate of heat addition
Qin=120 kW. The temperature at the beginning and the end of the
addition heat (combustion) are respectively: T2=900 K and T3=2100
K. Assume constant specific heats (Cp and Cv). The air properties
at a room temperature T1=293.0 K are: Cp=1.005 kJ/kg.K,
Cv=0.718KJ/kg.K, the gas constant of air is R=0.287 kJ/kg.K and the
ratio of specific heats k=1.4. Calculate:
a/ The network Wnet and the rate of the heat rejected Qout in
kW.
b/ The mass flow rate of the air mair.
c/ The cutoff ratio rc.and the compression ratio r.
d/ T4
In: Mechanical Engineering
(c) Draw a schematic graph of resolved shear stress versus shear strain for a single crystal of a pure metal. Clearly label the point of the critical resolved shear stress and the three subsequent stages of dislocation behaviour. Describe these three stages.
(d) Explain why the critical resolved shear stress is much lower than the theoretical strength, based on the force required to break atomic bonds within the structure.
In: Mechanical Engineering
5 example in industrial
-valve in i/c engine
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What distinguishes scientific and experiential disciplines?
| a) | Science is based on facts and is always right and cannot be falsifiable |
| b) | Scientific disciplines are more difficult to understand, teach and learn |
| c) | Experiential disciplines do not use the scientific process |
| d) | Experiential disciplines are based on standards and best practices and lack overarching principles, laws or axioms that can be applied to solving a wide variety of problems |
| e) | All of the above |
| f) | a and b only |
| b and d onl |
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One end of the straw is blocked by a finger when You pushed the other side of straw under water h_0 (m) and right after that finger is removed from end of straw. You can see the level of water in the straw is rising. Find the depth of water in the straw h(t). Consider the situation as quasi equillibrium state and neglect the surface tension.
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# sensors for process nonitoring : cutting process ..
- Briefly explain the process ( first explain it un general and then related with the sensor)
-- I need it typing and clear and at least 2 pages
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In Finite Element Analysis (FEA) What is a local stiffness matrix and a global stiffness matrix?
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Draw a simple circuit to open and close a double acting hydraulic cylinder.
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Q11 a) What is the basis for piston rod design? Explain the significance of area ratio.
b) List 4 of the likely causes for slow or erratic motion of an actuator in a hydraulic equipment.
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Mechanical vibration.
Examples of forced damped oscillation with harmonic force.
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An oven may be regarded as a cube, each side 1.2m long. The oven stands on thin legs and the heat transfer through each of the six faces is identical. The walls and doors are all made of a stainless steel lining (thermal conductivity 20W/mK) 2mm thick, a layer 75mm thick of insulating material (thermal conductivity 0.25W/mK) and a mild steel outer sheet (thermal conductivity 48.5W/mK) 3mm thick. If the inner wall temperature is 400oC and the outer surface temperature is 100oC calculate the rate of heat loss from the oven. Estimate the heat transfer coefficient between the oven and the surrounding air at 30oC
[8.63kW, 14.3W/m2K]
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In the Injection Moulding Process, thicker parts are more susceptible to shrinkage. Explain why this is the case.
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