4.65 A system consisting of 5 kg of air is initially at 300 kPa and 20 degrees C. Determine the heat transfer necessary to (a) increase the volume by a factor of two at constant pressure, (b) increase the pressure by a factor of two at constant volume, (c) increase the pressure by a factor of two at constant temperature, and (d) increase the absolute temperature by a factor of 2 at constant pressure.
In: Mechanical Engineering
What does it mean if my Back Work Ratio is 1?
In: Mechanical Engineering
Calculate the variation with Tt4 of exit Mach number, exit velocity, specific thrust. Fuel/air ratio, and thrust specific fuel consumption of an ideal turbojet engine for compressor pressure ratios of 10 and 20 at a flight Mach number of 2 and T0= 217K.Perform calculations at Tt4 values of 2400K, 2200K, 2000K and 1800K. Use hPR= 42,800kJ/kg, cp= 1.004kJ/kg and γ= 1.4.
In: Mechanical Engineering
3. As a tool experiences crater wear, in general, the deepest
point in the crater
formed on the tool rake face occurs at a distance away from the
tool tip,
rather than at the tool tip. Elucidate the physics behind this
observation.
In: Mechanical Engineering
15.Why is it not common to have milling cutters with negative
axial rake angle
and positive radial rake angle?
In: Mechanical Engineering
14. (i) For a turning operation that entails ideal conditions,
it is desirable to have
both the maximum roughness Rt and the machining time reduced by a
factor
of 2, without altering the spindle speed. By what factor should the
tool nose
radius be increased to achieve this? (ii) What limits the maximum
tool nose
radius in practice?
In: Mechanical Engineering
A compressor, operating at steady-state, increases the pressure of an air stream from 1 bar to 10 bar while losing 4.2 kW of heat to the surroundings. At the compressor inlet, the air is at 25o C and has a velocity of 14 m/s. At the compressor outlet, the air is at 350o C and has a velocity of 2.4 m/s. If the compressor inlet has a cross-sectional area of 500 cm2 and the air behaves as an ideal gas, determine the power requirement of the compressor in kW.
In: Mechanical Engineering
A compressor, operating at steady-state, increases the pressure of an air stream from 1 bar to 10 bar while losing 4.2 kW of heat to the surroundings. At the compressor inlet, the air is at 25o C and has a velocity of 14 m/s. At the compressor outlet, the air is at 350o C and has a velocity of 2.4 m/s. If the compressor inlet has a cross-sectional area of 500 cm2 and the air behaves as an ideal gas, determine the power requirement of the compressor in kW.
In: Mechanical Engineering
6. The uncut chip thickness for an end-milling application that
entails a cutter
with brazed inserts is 0.025 mm. For coating these tools would you
employ a
Chemical Vapor Deposition (CVD) or a Physical Vapor Deposition
(PVD)
process? Give three reasons to substantiate your answer.
In: Mechanical Engineering
5. Sketch two views of a turning operation to show that the back
rake angle and
the side rake angle correspond to the inclination angle and the
effective rake
angle, respectively.
In: Mechanical Engineering
1) A prototype disk brake for a bicycle is to be mounted on the hub of the rear wheel, and consists of a pair of pads of area 5cm × 1cm which are pressed against opposing faces of the steel disk. The pads are aligned with their longer dimension in the tangential rotation direction, with the pad centres at a distance of 10cm from the centre of the disk. The brake is to be tested on a rotating machine to simulate the loading and wear in service. The disk rotates at a suitable constant speed, and the brakes are applied for 10 seconds every minute, with each pad applying a normal load of 1 kN.
(a) Find a suitable rotation speed (in revs. per minute, rpm) if the test is to simulate braking a bicycle travelling at a speed of 20km/hour, with a wheel diameter (including the tyre) of 70cm.
(b) When the brakes are applied, the machine registers an increase in torque of 30 Nm. Find the friction force that is being applied to each pad, and hence estimate the friction coefficient.
(c) Estimate the depth of material removed per hour of testing, if the Archard wear constant for the materials is ka = 2×10-8 MPa-1.
(d) What other factors would influence the wear rate in service?
In: Mechanical Engineering
A turning operation in the automotive industry relates to the
reduction of the
diameter of bar stock by 6 mm for about 100,000 components. For a
constant
machining cycle time, would you recommend a single-pass operation
or a
multi-pass operation, from the point of view of tool life and
surface finish?
Why?
In: Mechanical Engineering
1. Considering heat transfer issues, give two reasons to
indicate why cutting
fluid applied in the form of a mist performs better in comparison
to a flood
application.
In: Mechanical Engineering
1a. Can we delete a drawing view in autodesk inventor? How?
1b. Can we adjust the length of centerlines in the draftingmode of inventor? how?
1c. Describe the purpose and usage of the leader text command
1d. Describe the advantage of using the 3D annotations in isometric drawins views approach as a documentation tol that is avaible in autodesk inventor
In: Mechanical Engineering
What are the differences between air-standard analysis and cold air-standard analysis? What is the tradeoff in using air-standard analysis vs. using cold air-standard analysis?
In: Mechanical Engineering