Water is discharged from a pipe outlet at a rate of 60l/s at 120.8 kPa absolute pressure. All pipes are 15 cm in diameter with a total length of 200 m. The total pipe length on the suction side is 10.8 m. Both reservoirs are big. The water surfaces are exposed to the atmosphere and the difference in their levels is 9 m.
Pipeline friction head loss is 0.086 m per meter length of pipe. On the suction side, fitting loss is 1.3 m while on the delivery side, fitting loss varies with the square of the velocity with K = 1.0.
a) Find the height of the water level above the pipe outlet in the receiving reservoir (m).
b) Find the total head loss of the system (m).
c) What is the hydraulic power (kW)?
d) The water to be pumped has a vapour pressure of 2335 N/m^{2}. The cavitation parameter, s = 0.12. Find the maximum pump height possible above the surface of the water in the supply reservoir (Show clearly the calculation of all heads involved).]
(Atmospheric pressure = 101.3 kPa).
In: Mechanical Engineering
The stream function ?? in a two-dimensional flow field is given as ?? = 4?? − 3?? + 7???? (a) Prove that this flow field is irrotational and that it satisfies the continuity equation. (b) Find the potential flow function Ф(??, ??) for this flow field with boundary condition Ф = 0 at x = 2, y = 1.
In: Mechanical Engineering
Why are the tolerance characteristics categorized as
forced
fitting and loose can't represent shape and position tolerance?
In: Mechanical Engineering
1. Control charts are usually expressed in terms of
average values and their dispersion.
Give an explanation (and the reason) about the condition of a
production system that is
stated in the control chart
2. From the results of the control chart analysis, how
to determine the correlation between
changes in product quality conditions for the causes?
In: Mechanical Engineering
2. Surface roughness of a machining product is an
important factor
determine the quality of geometry. Explain the following:
a. Explain how the surface roughness measurement tool works!
b. Explain the concept of measuring surface roughness!
c. How are the surface measurements results stated (written
down)?
In: Mechanical Engineering
In: Mechanical Engineering
At the beginning of compression of an ideal Diesel cycle the gas has a temperature and pressure of 40^{0}C and 90 kN/m^{2}, respectively. The volume ratio of compression is 16:1. The maximum temperature of the cycle is 1400^{0}C. Determine, for the cycle,
Take, γ=1.4 , cp = 1.004 kJ/kg K.
In: Mechanical Engineering
One kilogram of air is taken through a constant volume cycle. At the commencement of the adiabatic compression, the pressure and temperature are 103 kN/m^{2} and 100^{0}C respectively. The adiabatic compression has a volume ratio of 6:1. The maximum pressure of the cycle is 3.45 MN/m^{2}. Determine, for the cycle,
For the air, take, R = 0.287 kJ/kg K, γ=1.4
In: Mechanical Engineering
A cooling plant adopted a two-stage cascade refrigeration system
to meet the required cooling load. In both upper and lower cycles,
the refrigerant leaves condenser as saturated liquid and enters
compressor as saturated vapor. The isentropic efficiency of the
upper cycle compressor is 80 %, while the lower cycle compressor is
70% efficient. The pressure limits of the upper and lower cycles
are 1 MPa and 0.2 MPa with refrigerant-134a, respectively. Heat
rejection from the lower cycle to the upper cycle takes place in an
adiabatic counterflow heat exchanger where the lower cycle enters
about at 0.5 MPa and the upper cycle enter about at 0.32MPa. If the
mass flow rate of the refrigerant in the upper cycle is 0.28 kg/s,
determine
i. the mass flow rate of the refrigerant in the lower cycle
ii. the rate of heat removal from the refrigerated space and the
power input into the compressors
iii. the COP of the refrigerator,
In: Mechanical Engineering
Evaluate the proportion of the heat of fuel carried away by the
flue gases for the following data: Coal with Calorific Value of 30
MJ/kg has composition by mass as follow: C= 78%, H=5%, 0,=8%, S=2%,
N_{2}=2% and the remaining is ash. The coal is burnt in the
furnace with 50% excess air. The flue gases leaving the chimney at
327°C and the atmospheric temperature is at 15 °C. Assume perfect
combustion. Specific heat for dry product (C_{p}) is
1045J/kg. Heat is carried away per kilogram of moisture in the flue
gas is 3000kJ/kg. The composition of air by mass is as follow:
0_{2} = 23% and N_{2}= 77 %.
(20 marks, C5)
In: Mechanical Engineering
A cooling plant adopted a two-stage cascade refrigeration system to meet the required cooling load. In both upper and lower cycles, the refrigerant leaves condenser as saturated liquid and enters compressor as saturated vapor. The isentropic efficiency of the upper cycle compressor is 80 %, while the lower cycle compressor is 70% efficient. The pressure limits of the upper and lower cycles are 1 MPa and 0.2 MPa with refrigerant-134a, respectively. Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counterflow heat exchanger where the lower cycle enters about at 0.5 MPa and the upper cycle enter about at 0.32MPa. If the mass flow rate of the refrigerant in the upper cycle is 0.28 kg/s, determine
i. the mass flow rate of the refrigerant in the lower cycle
ii. the rate of heat removal from the refrigerated space and the power input into the compressors
iii. the COP of the refrigerator
In: Mechanical Engineering
Evaluate the proportion of the heat of fuel carried away by the flue gases for the following data: Coal with Calorific Value of 30 MJ/kg has composition by mass as follow: C= 78%, H=5%, 02,=8%, S=2%, N2=2% and the remaining is ash. The coal is burnt in the furnace with 50% excess air. The flue gases leaving the chimney at 327°C and the atmospheric temperature is at 15 °C. Assume perfect combustion. Specific heat for dry product (Cp) is 1045J/kg. Heat is carried away per kilogram of moisture in the flue gas is 3000kJ/kg. The composition of air by mass is as follow: 02 = 23% and N2= 77 %.
In: Mechanical Engineering
Taichung thermal power station wants to change their steam generator with a new steam generator that has a better efficiency. The existing steam generator operating with Rankine cycle with reheat and has a thermal efficiency of 30%. Taichung thermal power station has been offered by Patron Company that supplies new steam generators that are more environmentally friendly. The specifications of the new steam generator are as follow: maximum pressure is 15MPa, minimum pressure is 10kPa Temperature entering the turbine is 500°C. Isentropic efficiency of the pump is 85%
Taichung thermal power station wants the new steam generator to have vapor content of the steam to exceed 90% and the steam mass flow rate is 12kg/s. Evaluate: i. the pressure at which the reheat cycles takes place (12 marks, C5) H. the total rate of heat in the boiler (4 marks, C5) Hi. Does the new steam generator have higher thermal efficiency of the cycle than the current generator? Justify your answer.
In: Mechanical Engineering
In an ideal standard dual cycle, the pressure and temperature at the beginning of compression are 1 bar and 47°C, respectively. The heat supplied in the cycle is 1250kJ/kg, two third of this heat is being added at constant volume and the remaining heat is added at constant pressure. If the compression ratio is 16, determine
i. the maximum temperature in cycle
ii. thermal efficiency of the cycle
iii. the mean effective pressure
In: Mechanical Engineering
A tractor is pulling a drawbar tillage implement at a ground speed of 1.6 m/s. The total rear axle static load is 35 kN, the wheelslip is 0.1, and the value of mobility number for the particular tyre and soil is 2.84. The driving tyre radius is 0.6 m, and the engine speed is 2100 rpm, and the overall gear transmission mechanical efficiency is 79%.
Calculate the drawbar pull, drawbar power and the tractive efficiency
Calculate the wheel axle power
Calculate the overall transmission ratio
Calculate the engine power
Calculate the engine torque.
In: Mechanical Engineering