In: Mechanical Engineering
In a manufacturing process, stainless steel cylinders (AISI 304) initially at 600K are quenched by submersion in an oil bath maintained at 300K with h=500W/m2-K. Each cylinder is of length 2L=60 mm and diameter D=80mm. Consider a time 3 min into the cooling process and determine the temperatures at the center of the cylinder, at the center of the circular face and at the mid height of the site. (Use the Heisler charts to answer these questions). You may evaluate properties at the mean temperature of Tm=450K.
In: Mechanical Engineering
A large block having the properties of a chrome brick at 200oC is at uniform temperature of 30oC when it is suddenly exposed to a constant surface flux of 3x104 W/m2. For this case, determine:
a. The temperature at a depth of 3 cm after a time of 10 min
b. The surface temperature at this time
In: Mechanical Engineering
An air compressor rapidly fills a 0.3m3 tank (there is no heat transfer through the tank walls), initially containing air at 27 ?C, 1 atm, with air drawn from the atmosphere at 27? ?C, 1 atm. During filling, the relationship between the pressure and specific volume of the air in the tank is pv1.4 = constant. You can model the air as an ideal gas with constant specific heats at 300K.
Calculate (and show your work) the tank’s pressure and temperature, and the
work input to the compressor for the case of m/m1 = 1.5, where m1 is the initial mass in the tank and m is the mass in the tank at any time after filling starts
Plot the pressure, in atm of the air within the tank versus the ratio of m/m1
Plot the temperature, in ?C, of the air within the tank versus the ratio of m/m1
Plot the compressor work input, in Btu, versus m/m1.
For all three graphs, let m/m1 vary from 1 to 3 in increments of 0.1
In: Mechanical Engineering
An air compressor rapidly fills a 0.3m3 tank (there is no heat transfer through the tank walls), initially containing air at 27 ?C, 1 atm, with air drawn from the atmosphere at 27? ?C, 1 atm. During filling, the relationship between the pressure and specific volume of the air in the tank is pv1.4 = constant. You can model the air as an ideal gas with constant specific heats at 300K.
Calculate (and show your work) the tank’s pressure and temperature, and the
work input to the compressor for the case of m/m1 = 1.5, where m1 is the initial mass in the tank and m is the mass in the tank at any time after filling starts
Plot the pressure, in atm of the air within the tank versus the ratio of m/m1
Plot the temperature, in ?C, of the air within the tank versus the ratio of m/m1
Plot the compressor work input, in Btu, versus m/m1.
For all three graphs, let m/m1 vary from 1 to 3 in increments of 0.1
In: Mechanical Engineering
Water at p1 = 20 bar, T1
= 400oC enters a turbine operating at steady state and
exits at p2 = 1.5 bar, T2 =
220oC. The water mass flow rate is 4000 kg/hour. Stray
heat transfer and kinetic and potential energy effects are
negligible.
Determine the power produced by the turbine, in kW, and the rate of
entropy production in the turbine, in kW/K.
In: Mechanical Engineering
Draw the electrical circuit diagram of electromagnetic forming, label it neatly and explain how a thin cylinder can be expanded or compressed by this process.
In: Mechanical Engineering
A solid cylinder of 6 inch diameter and 4 inch high is
compressed axisymmetrically to 2 inch high.
a) Calculate the final diameter of the product, the three
orthogonal strains and the Von Mises strain.
b) Estimate the maximum total force required for this operation.
Assume: coefficient of fricition 0.2; Use Ludwik's Law to find the
pressure at maximum axial strain; the strength coefficient of the
workpiece: K is 147 ksi, strain hardening exponent is 0.17.
In: Mechanical Engineering
What is the percentage change in the R-value of the window if double glazed window is used with 6.4 mm and 12.7 mm air in between as compared to single glazed window? Does the resistance increase linearly with the thickness of the space?.
In: Mechanical Engineering
1a. Write the three-dimensional state of uniform stress in a deformable medium
1b.
. Show from table below that total true stain is equal to the sum of the incremental true strains. Consider a rod of 2 cm long that is elongated in three increments, each has a strain of 0.1.
|
Increment |
length |
e |
|
0 |
2 |
0.1 |
|
1 |
2.20 |
0.1 |
|
2 |
2.42 |
0.1 |
|
3 |
2.662 |
0.1 |
In: Mechanical Engineering
Which is the most efficient? A parallel hydrogen fuel cell or one connected in series? Can you explain your reasoning to your answer?
In: Mechanical Engineering
Describe the mathematical models of the boundary value problem to evaluate the elastic deflection of the beam based on Euler-Bernoulli and Timoshenko theories with finite difference discretisation (for numerical integration and differentiation)
In: Mechanical Engineering
A 40 wt% Pb–60 wt% Mg alloy is heated to a temperature within the a liquid-phase region. If the mass fraction of each phase is 0.5,
then estimate
(a) the temperature of the alloy
(b) the compositions of the two phases in weight
percent
(c) the compositions of the two phases in atom
percent
In: Mechanical Engineering
A 40 wt% Pb–60 wt% Mg alloy is heated to a temperature within the a liquid-phase region. If the mass fraction of each phase is 0.5,
then estimate
(a) the temperature of the alloy
(b) the compositions of the two phases in weight
percent
(c) the compositions of the two phases in atom
percent
In: Mechanical Engineering
In: Mechanical Engineering