List, draw and explain the strengthening mechanisms for metals. Why we are using this techniques?
In: Mechanical Engineering
An ideal gas-turbine cycle with two stages of compression and two stages of expansion. The overall pressure ratio is 9. The air enters each stage of the compressor at 300 K and each stage of the turbine at 1200 K. assuming an efficiency of 86 percent for each compressor stage and an efficiency of 90 percent for each turbine stage. Draw the T-S diagram and determine the back work ratio and the thermal efficiency of the cycle, assuming (a) no regenerator is used and (b) a regenerator with 85 percent effectiveness is used.
In: Mechanical Engineering
A Dual cycle engine is analyzed using the air standard method. Given the conditions at state 1, compression ratio (r), pressure ratio (rp), and cutoff ratio (rc) determine the efficiency and other values listed below.
Note: The gas constant for air is R=0.287 kJ/kg-K.
Given Values
T1 (K) = 334
P1 (kPa) = 115
r = 11.5
rp = 1.34
rc = 1.14
a) Determine the specific internal energy (kJ/kg) at state 1.
b) Determine the relative specific volume at state 1.
c) Determine the relative specific volume at state 2.
d) Determine the temperature (K) at state 2.
e) Determine the pressure (kPa) at state 2.
f) Determine the specific internal energy (kJ/kg) at state 2.
g) Determine the temperature (K) at state 3.
h) Determine the pressure (kPa) at state 3.
i) Determine the specific internal energy (kJ/kg) at state 3.
j) Determine the specific enthalpy (kJ/kg) at state 3.
k) Determine the temperature (K) at state 4.
l) Determine the pressure (kPa) at state 4.
m) Determine the specific enthalpy (kJ/kg) at state 4.
n) Determine the relative specific volume at state 4.
o) Determine the relative specific volume at state 5.
p) Determine the temperature (K) at state 5.
q) Determine the pressure (kPa) at state 5.
r) Determine the specific internal energy (kJ/kg) at state 5.
s) Determine the net-work per cycle (kJ/kg) of the engine.
t) Determine the heat addition per cycle (kJ/kg) of the engine.
u) Determine the efficiency (%) of the engine.
In: Mechanical Engineering
Two electric bulbs of 100 ohms are used for 8 hours daily. What is the cost of them for 1 day if the rate is 75 paise per unit?
In: Mechanical Engineering
No steering from remote control
I NEED GOOD ANSWER AND WRİTE WORD
In: Mechanical Engineering
1. You are to do a preliminary design study for a small
demonstration steam turbine power plant.
- Steam will be provided by a small steam generator fired by
natural gas. - Your system will take in steam at 30 bar
and 400 oC.
- The steam passes through a two stage turbine. At a pressure of 10
bars, the steam leaves the first stage of the turbine and will pass
through a reheat loop in the steam generator which will boost the
temperature back up to 400 oC at this pressure. The steam will then
enter the second stage of the turbine.
- When the steam leaves the turbine, the quality should be at least
95% at the turbine exit / condenser inlet.
- The design condenser pressure is 0.70
bar.
- Heat is removed from the condenser and rejected to the
environment through a cooling tower.
a) Assuming isentropic expansion, what are the temperature,
enthalpy, and entropy of the steam when it leaves the first stage
of the turbine? (5 pts)
b) What are the enthalpy and the entropy of the steam as it leaves
the reheater and enters the second stage of the turbine? How much
heat (kJ/kg) goes into the steam in the reheat process? (10
pts)
c) Based on an isentropic expansion, what will the quality be at
the exit? Will it meet this design limit? (10 pts)
For the following parts use the design turbine power output of 2.5
kW.
d) What mass flow rate is required? (10 pts)
e) At what rate must heat be produced by natural gas burners in the
steam generator to produce the steam at the turbine inlet, and how
much heat must be produced to reheat the steam between the stages?
For a heating rate range of 950-1150 BTU/scf and a cost of $8 per
100 cubic feet, what is the fuel cost per hour to run this unit?
(10 pts)
f) What is the feed water pump power demand, and what is the BWR?
(10 pts)
2. A refrigeration machine has been designed based on R134a. The
design capacity is 15 tons. The evaporator coil design
temperature is 8 oC. The refrigerant enters the compressor as a
slightly superheated vapor at 15 oC. The condenser coil design
pressure is 14 bar. Refrigerant enters the expansion valve as a
compressed (subcooled) liquid at 44 C. Note that the temperature of
the air passing over the tubing in the evaporator coil will be
higher than 8 oC and the temperature of the air passing over the
condenser coil will be lower than the coil temperature. Use 80% for
the compressor isentropic efficiency.
a. Calculate the power required to run the compressor under these
design conditions and the required mass flow rate of R134a. (30
pts)
b. Find the rate of heat transfer for the condenser (high pressure
side) of the system. (15 pts)
c. Find the quality of the refrigerant as it enters the evaporator.
(10 pts)
3. A small gas turbine engine is used to produce power for
auxiliary systems. This is a simple gas turbine open to the
atmosphere. Air enters the compressor at 1 bar, 300 K. The
compressor pressure ratio is 3.5:1. After passing through the
combustion chamber, the air enters the turbine at a temperature of
1300 K. Determine the mass flow rate of air needed for the turbine
to produce 60 kW of power. Also determine the heat that must be
generated in the combustors. (30 pts) Solar collector …
In: Mechanical Engineering
Explain one application of portable CMM(Coordinate Measuring
Machine) in the automobile field with
details.
In: Mechanical Engineering
An open tank has a vertical rectangular gate as a partition, and on one side contains gasoline. The rectangular gate, that is 5 m high and 2 m wide, is hinged at the bottom end of the partition. A stopper is located at the top end of the gate, which only allows the gate to swing open towards the gasoline side of the tank. Water is slowly added to the empty side of the tank. If the depth of the gasoline is 4.5 m, determine the depth of the water when the gate is about to open.
In: Mechanical Engineering
Air flows through a nozzle which has inlet areas of
(10 cm2
). If the air has a velocity of (120 m/s) a
temperature (300K) and a pressure of (700kpa) at the inlet section
and a pressure of (250kpa) at the exit,
find the mass flow rate through the nozzle and the velocity at the
exit of the nozzle, assuming one-
dimensional isentropic flow. (R=287 J/kg. K), (K=1.4). (25%)
In: Mechanical Engineering
An adiabatic gas turbine uses air to produce work. Air expands adiabatically from 600 kPa and 287 C to 90 kPa and 67 C. Take specific heats at room temperature (300 K). a) Find the isentropic efficiency of the turbine. b) Find the work produced by the turbine for a mass flow rate of 2.5 kg/s. c) If the mass flow rate of air is again 2.5 kg/s, find the entropy generation under steady conditions
In: Mechanical Engineering
Two long concentrie cylinders have diameters of 5 and 10
cm, respectively. The inside cylinder is at 900 C and the outer
cylinder is at 100-C. The inside and outside emisivities are 0.8
and 0.4, respectively. Calculate:
a) the percent reduction in heat transfer if a cylindrical radiation
shield having a diameter of 6 cm and emisivity af 0.3 is placed
between the two cylinders.
b)discuss the effect of decreasing the shield diameter on the
percent reduction in heat transfer
c)draw the network circuit
cxraw the network circuit
In: Mechanical Engineering
Dislocations can work as sinks and sources of vacancies. Explain.
In: Mechanical Engineering
A Dual cycle engine is analyzed using the cold air standard method. Given the conditions at state 1, compression ratio (r), and cutoff ratio (rc) determine the efficiency and other values listed below.
Note: The specific heat ratio and gas constant for air are given as k=1.4 and R=0.287 kJ/kg-K respectively.
Given Values
T1 (K) = 316
P1 (kPa) = 170
r = 18
rp = 1.44
rc = 1.22
a) Determine the specific internal energy (kJ/kg) at state 1.
b) Determine the temperature (K) at state 2.
c) Determine the pressure (kPa) at state 2.
d) Determine the specific internal energy (kJ/kg) at state 2.
e) Determine the temperature (K) at state 3.
f) Determine the pressure (kPa) at state 3.
g) Determine the specific internal energy (kJ/kg) at state 3.
h) Determine the specific enthalpy (kJ/kg) at state 3.
i) Determine the temperature (K) at state 4.
j) Determine the pressure (kPa) at state 4.
k) Determine the specific enthalpy (kJ/kg) at state 4.
l) Determine the temperature (K) at state 5.
m) Determine the pressure (kPa) at state 5.
n) Determine the specific internal energy (kJ/kg) at state 5.
o) Determine the net-work per cycle (kJ/kg) of the engine.
p) Determine the heat addition per cycle (kJ/kg) of the engine.
q) Determine the efficiency (%) of the engine.
In: Mechanical Engineering
In: Mechanical Engineering
USE EXCEL TO SOLVE
After heat treatment, the 2-cm thick metal plates (k = 180 W/m·K, ρ = 2800 kg/m3, and cp = 880 J/kg·K) are conveyed through a cooling chamber with a length of 10 m. The plates enter the cooling chamber at an initial temperature of 500°C. The cooling chamber maintains a temperature of 10°C, and the convection heat transfer coefficient is given as a function of the air velocity blowing over the plates h = 33V0.8, where h is in W/m2·K and V is in m/s. To prevent any incident of thermal burn, it is necessary for the plates to exit the cooling chamber at a temperature below 50°C. In designing the cooling process to meet this safety criteria, use EXCEL software to investigate the effect of the air velocity on the temperature of the plates at the exit of the cooling chamber. Let the air velocity vary from 0 to 40 m/s, and plot the temperatures of the plates exiting the cooling chamber as a function of air velocity at the moving plate speed of 2, 5, and 8 cm/s
In: Mechanical Engineering