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A machine of mass 500kg is mounted through four rubber mountings that exhibit linear elasticity and viscous damping.in the installation of the machine ,each pad was observed to undergo a compression of 15mm. During the trial run of the machine ,the system was observed to execute free samples vibration such that it made 50 oscillations in 15 seconds.For this system,find;
a)the stiffness and damping coefficient of each mounting.
b)the minimum number of oscillations and consequently the time it will take for the amplitude of oscillations to be reduced to 1%.
what is thermal constancy?
The fig figure below shows water flowing through a pipe reducer. the static pressure at(1) and (2) are measured using the manometer with a fluid of SG < 1 find( by applying Bernoulli's equations) a) barometer reading X=f (Q,A1,A2,SG)
b)p1-p2=f(theta,r,SG,L)
c)if the vapour pressure of the water at the prevailing conditions is p=1.765kPa ,what the minimum area ratio(A2/A1) to prevent cavitation.
Assume P1/P2=5.6,SG=0.85,Q=0.05m3/s,D1=0.3m,L=1.5m and theta=30°
Carry out a series of calculations on the same diatomic molecule you were assigned in class. The sequence of steps is given below. Do this for two semi-empirical methods (AM1 and PM3) and then two ab initio methods. For the two ab initio methods choose the Small(3-21G) and Large(6- 31G**) basis sets. In all cases just use the other default settings. (a) Draw the molecule. (b) Select a method (semi-empirical or ab initio). (c) Optimize the geometry and note the bond length. (d) Do a single point calculation. (e) Do a vibrational calculation. (f) Display the vibrational results and note the vibrational frequency. Use the NIST database to obtain experimental values of the bond length and vibrational frequency. Compare these with your calculated results. Turn in a summary of your findings.
Liquid ethanol (C2 H5 OH) is burned with 150% theoretical oxygen in a steady-state, steady-flow process. The reactants enter the combustion chamber at 25 ◦ C and the products leave at 65 ◦ C. The process takes place at 1 bar. Assuming complete combustion (i.e. CO2 and H2 O as products along with any excess O2 ), calculate the heat transfer per kmole of fuel burned.
6.2 Gaseous propane at 25 ◦ C is mixed with air at 400 K and burned. 300% theoretical air is used. What is the adiabatic flame temperature? Again, assume complete combustion.
6.3 Repeat Problems 6.1 and 6.2 using CEA2. Compare the product composition using CEA2 with the assumption of complete combustion. What do you observe?
Using CEA2, calculate the equilibrium composition of a mixture of 1 mol of CO2 , 2 mol of H2O, and 7.52 mol of N2 at 1 bar and temperatures ranging from 500 to 3000 K in steps of 100 K. Then plot the mole fraction of NO as a function of temperature.
QUESTION 1 GEARS [40]
1.1 Write a problem statement to verify spur gear set material selected from Table
6.9, page 127 of the prescribed textbook.
(3)
1.2 Elaborate on the product design specification for the design of the spur gear
set (Figure 1 above) referring to the performance aspect, consider the
transmission of power, the gear ratio, and efficiency.
(6)
1.3 Verify the suitable material for pinion and gear (Figure 1 above) based on
Lewis’ formula if both the pinion and gear were selected from Table 6.9, page
127.
(31)
QUESTION 2 MINIMUM DIAMETER OF THE OUTPUT SHAFT [10]
2.1 The output solid steel shaft is supported by the ball bearings, as shown in
Figures 1 & 2 above. The shaft operates at room temperature. Determine the
minimum allowable diameter of the output shaft based on ASME CODE and
select the standard size of the shaft from the Macsteel catalogue, provided
with the question paper.
The request for this project is to design the diameter of the output shaft of a single reduction gearbox with a 20⁰ pressure angle involute spur gear set. The gearbox consists of two (2) shafts, four (4) bearings, two (2) spur gears, and gearbox steel casing, as shown in Figure 1 below. The gearbox is powered by a 3 kW Power, 50 Hz AC electric motor with a speed of 1440 rpm. The main goal of the gearbox is to reduce the speed to 575 rpm. The gearbox had to abide by the following: 1. The weight of the motor and gears do not add to the bending or shear stresses of the system and will be ignored when doing calculations. 2. The entire system is bolted to a horizontal bedplate and will only be accessible from the top surface. 3. The machine components, including bolts, shafts, and bearings, must all be designed with a factor of safety (ns) as 2.5.
A 10 pole, 50 Hz, Y connection 3-phase induction motor having a rating of 60 kW and 415V.
The slip of the motor is 5% at 0.6 power factor lagging. If the full load efficiency is 90%,
calculate:
(i) Input power
(ii) Line current and phase current
(iii) Speed of the rotor (rpm)
(iv) Frequency of the rotor
(v) Torque developed by the motor (if friction and windage losses is 0)
A 60 Hz, three-phase. 6 – pole, Y-connected induction motor produces 100 hp at 1150 rpm. The
friction and windage losses of the motor are 1.2 kW, the stator copper and core losses are 2.1.kW
Compute the input power and the efficiency of the motor
