Calculate the heat of combustion and the stoichiometric fuel to air ratio (mass and molar) for 1) Methane and 2) Octane. Comment on whether the assumption of f<<1 is valid for these conditions.
In: Mechanical Engineering
Refrigerant 134a at p1 = 30
lbf/in2, T1 =
40oF enters a compressor operating at steady state with
a mass flow rate of 400 lb/h and exits as saturated vapor at
p2 = 160 lbf/in2. Heat
transfer occurs from the compressor to its surroundings, which are
at T0 = 40oF. Changes in kinetic and
potential energy can be ignored. The power input to the compressor
is 4 hp.
Determine the heat transfer rate for the compressor, in Btu/hr, and
the entropy production rate for the compressor, in
Btu/hr·oR.
In: Mechanical Engineering
A P - 51 Musta ng (WWII plane) is tested in the large wind tunnel at NASA Ames. The plane has a pitot - static probe system mounted. We want to test the P - 51 at a flight speed of 160 mph and altitude of 40,000 ft. T he wind tunnel’s test section has a cross - sectional area of 5000 ft 2 and a reservoir area of 100,000 ft 2 .
What pressure is needed in the reservoir to drive this flow?
a. Does Bernoulli’s equation apply here? i. Hint: What flow condition is required for Bernoulli’s equation?
b. If 1 60 mph is the true airspeed, what is the static and stagnation pressure? i. Hint: You are given the flight altitude as 40,000 ft.
c. W h at reservoir pressure is needed to achieve this test section velocity and pressure?
In: Mechanical Engineering
The metal titanium, which is useful in making alloys to resist high temperatures and extremely corrosive environments, adopts two crystal structures – close-packed hexagonal (α-phase) at room temperature and body-centred cubic (β-phase) above 882 °C. Under favourable circumstances, the α phase can dissolve up to 32 atomic % (nearly 15 wt %) of oxygen whereas the β phase can dissolve very little oxygen at the transition temperature (882 °C) and a little more at higher temperatures. Oxygen atoms have a radius of approximately 0.7 x 10-10 m.
a) Given that the “distance of closest approach” between two titanium atoms is approximately 2.92 x 10-10 m, calculate the radii of the octahedral and tetrahedral interstices in both the hexagonal and cubic forms of titanium. .
Answer..................................................................................................................... ..............................................................................................................................
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b) Use your answers to part a) to explain why the solubility of oxygen is different in the two structures of titanium? .
Answer:................................................................................................................................................ .......................................................................................................................................................................... .......................................................................................................................................................................... .......................................................................................................................................................................... ..................................................................................................................................................................
c) Can you explain how a metal that is capable of dissolving so much oxygen below 882 °C can simultaneously have excellent oxidation resistance? .
Answer:................................................................................................................................................. .......................................................................................................................................................................... .......................................................................................................................................................................... ..........................................................................................................................................................................
In: Mechanical Engineering
Autodesk Inventor 2019 Essentials Plus: Creating and Editing Sketched Features
If the answer is FALSE write a complete sentence explanation of why the answer is FALSE.
1.What is a base feature?
2.When creating a revolve feature, which objects can be used as an axis of revolution?
3.Explain how to create a linear diameter (diametric) dimension on a sketch.
4.Name two ways to edit an existing feature.
5.True__ False__ Once a sketch becomes a base feature, you cannot delete or add constraints, dimensions, or objects to the sketch.
6.True__ False__ By default geometry that is projected from one face to a sketch will update automatically based on changes to the original projected geometry.
7.Explain what the Asymmetric option does for the extrude and revolve commands.
8.Where do you set the physical material property of a part?
9.True__ False__ After setting a part’s material properties, the Appearance setting in the Quick Access Toolbar must be set to Color Matching for the appearance to match the material of the part.
10.True__ False__ By default, when a feature is deleted, the feature’s sketch will be maintained.
In: Mechanical Engineering
Would you like to explain more to me relate with Course Mechanical Behaviour in 50-70 word
a. Stress
b. Shear stress
c. Strain
d. Elongation
e. Safety Factor
f. Deflection
g. Deformation
h. Modulus Young
In: Mechanical Engineering
Determine the chimney height required to preserve design flow in a natural recirculation boiling water reactor channel with the following characteristics:
System pressure: 7.136 MPa
Reactor height 1.83 m
Feedwater temperature 260 Celsius
Combined pressure in losses in the channel, chimney, and downcomer: 1344.5 Pa
Average channel density in the core: 642.9 kg / m^3
Two-phase friction losses in the chimney 137.9 Pa
Friction losses in the downcomer: 68.9 Pa
Friction drop in channel: 606.7 Pa
Average exit void fraction: 44%
Feedwater added near the top of chimney
In: Mechanical Engineering
Explain in brief, the importance of Energy Auditing and Energy
Management. With the use of a case
study, explain its significance at your workplace.
In: Mechanical Engineering
The hydrogen gas of question one passes through a pipe network and now has a static pressure of 1 atmosphere, temperature of 293 K and a Mach number of 1.7. Let ? = 1.4. It then encounters a normal shock wave. What is the temperature, pressure and Mach number downstream of the shock wave?
In: Mechanical Engineering
4.3 Brief give the command for exporting your design
from CAD to the rapid prototyping
machine or 3D printer. (5)
In: Mechanical Engineering
1. To obtain a solution through superposition of solutions, describe the number of non-homogeneous conditions per sub-problem.
2. Discuss the relevance of shape factors.
3. Discuss the requirements for using the superposition method of solution.
4. Describe what is meant by eigen-problem solution in heat transfer.
5. Discuss what values a separation constant can attain during the separation of variables method of solution.
In: Mechanical Engineering
y'=y-x^2 ; y(1)= -4
Write a MATLAB program that makes two plots of the solution to the equation using the following values. Suggest you use nested loops instead of two different loops. Be sure to label your plots.
a. x0 = 1.0, step size h = .2, number of steps n = 20.
b. x0 = 1.0, step size h = .05, number of steps n = 80.
In: Mechanical Engineering
In: Mechanical Engineering
A 3"-diameter, 5"-long gas-piston assembly contains air at STP. (STP: Standard Temperature and Pressure conditions, 300K and 1 atm. At these conditions the air density is approximately 1.2kg/m3.) Calculate the necessary piston displacement in order to increase the pressure to 45 atm (typical of a diesel engine) varying linearly with displacement (i.e. the pressure varies linearly with displacement) during an adiabatic compression that will increase the gas’ internal energy by 1.2kJ.
In: Mechanical Engineering
Why is it a good idea to create value stream process maps?
In: Mechanical Engineering