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Water at 2.5 Mpa and 200°C is heated at constant temperature up to a
quality of 80%. Find (a) the quantity of heat received by the water, (b) the
change in internal energy, and (c) the work of nonflow process. (HINT:
table 4 needed)
Five kg of water vapour are contained at 150 kPa ad 90 per cent quality in a
suitable enclosure. Calculate the heat which must be added in order to just
produce a saturated vapor. What will the pressure be at the end of the
heating process?
design a flat belt (cross) to drive. the center distance between shafts is 5 m, velocity ratio=2.25, angular speed 600 rpm of the driving pulley, 60 hp, light shock.
a one dimensional steady flow is given by the following velocity;
"u=\\frac{2}{\\gamma+1}(\\frac xt-a_0)"
And density field;
"\\frac{\\rho}{\\rho_0}=(\\frac{\\gamma -1}{\\gamma+1}\\frac xt\\frac{1}{a_0}+\\frac{2}{\\gamma+1})^{\\frac{2}{\\gamma-1}}"
a)Calculate the substantial change of density.
b) check the validity of the continuity equation
"\\frac{D\\rho}{Dt}+\\rho\\frac{\\partial u}{\\partial x}=0"
for this flow field.
Explain the difference between an isothermal and an adiabatic expansion of a gas .
20020 m ^ 3 the gas in question 7 at a pressure of 1 bar is compressed to 70020 m ^ 3 adiabatic change . Calculate the:
a) ratio of the specific heat capacities y
b) final pressure
Explain briefly why a gas has two specific heat capacities.
0.28 kg of a gas is heated from 29 °C to 68°C. The specific heat capacity of the gas at constant volume is Cv = 0.72 kJ/kgK and the specific heat capacity at constant pressure Cp =1.01 kJ/kgK Calculate the change in:
a) Enthalpy
b)Internal energy
c) Flow energy
An air compressor works with a compression ratio 6:1 . If the incoming air is at a pressure of 1 bar and temperature of 20 degrees °C , calculate the final air pressure if the final temperature is 68 °C . Note : 1bar = 100 * 10 ^ 3 * Pa
A simple hydraulic jack has a pump piston diameter 38.13 mm , and a load piston 190.65 mm . Calculate:
a) the effort force needed to lift a load of 1300 Newton
b) The distance moved by the load if the effort moves a distance 285
A manometer is used to measure the gas pressure supply to a boiler. One side is connected to the supply and the other is open to the atmosphere . The manometer contains water (density 1000 kg/m^ 3 ). Calculate the gauge pressure if the head is 560 mm. How would you find the absolute pressure of the gas supply?
A journal runs in a bearing diameter , 25mm , and length 100 mm at 25 . The clearance gap is 0.8 mm . The lubricant used has a dynamic viscosity of 80 CP . The bearing must carry a side load of 800N . Calculate the values of:
a) the friction force
b) coefficient of friction
Note : 1cP = 1mPa - s
