last resort Flashcards
Self-ignition would occur in the engine using
certain brand of petrol if the temperature due to
compression reached 350°C. Calculate the highest
ratio of compression that may be used to avoid preignition if the law of compression is
PV1.3 = c
PV1.4 = c
Calculate the final pressure in each
11.36, 6.19, 23.5 bar, 12.8 bar
Calculate the density of Ethane at 171 bar and
458K; assume for Ethane:
TC = 305 K
PC = 48.80 bar
R = 319.3 J/kg-K
a) Assume it behaves as a perfect gas.
b) Using the compressibility chart
117 KG/M3, 146
Find the specific volume for H2O at 10 MPa and
500°C using:
a) Compressibility chart;
b) Steam tables
: 0.032 m3
/kg; 0.03279 m3
/kg
Determine the pressure of water vapour at 300°C, if
its specific volume is 0.2579 m3
/kg, using the
following method:
a) Ideal gas equation
b) Van-der-Waals equation
1,025, 1.006
An unknown gas has a mass of 1.5 kg contained in
a bottle of volume 1.17 m3 while at a temperature of
300K, and a pressure of 200 kPa. Determine the
ideal gas constant and deduce the gas?
520, 15.99
A 6 m3 tank contains helium at 400K is evacuated
form atmospheric pressure of 100 kPa to a final
pressure of 2.5 kPa. Determine
a) The mass of helium remaining in the tank;
b) The mass of helium pumped out;
c) If the temperature of the remaining helium falls
to 10°C, what is the pressure in kPa?
0.018 kg; 0.704 kg; 1763 Pa
A motorist equips his automobile tyres with a relieftype valve so that the pressure inside the tyre will
never exceed 220 kPa (gauge). He starts the trip
with a pressure of 200 kPa (gauge) and a
temperature of 23°C in the tyres. During the long
drive the temperature of the air in the tyres reaches
83°C. each tyre contains 0.11 kg of air. Determine:
a) the mass of air escaping each tyre;
b) the pressure of the air inside the tyre when the
temperature returns to 23°C
0.0094, 183
300 kg/minute of steam at 3 MPa and 400°C is
supplied to a steam turbine. Determine the potential
heat released from steam if it is condensed at
constant pressure. Can you deduce the specific heat
of the steam under this condition?
Q = 2133.5 kW; Cp = 4.009 kJ/kg-K
Self-ignition would occur in an engine using certain
brand of petrol if the temperature due to
compression reaches 350°C; when the inlet
condition is 1 bar, 27°C.
Calculate the highest compression ratio possible in
order to avoid self-ignition, if the compression is
according to
a) Adiabatic, with index of 1.4; and
b) Polytropic, with index of 1.3.
6.2,11.4
The gas in an internal combustion engine, initially
at a temperature of 1270°C; expands polytropically
to five times its initial volume and one-eight its
initial pressure. Calculate:
a) The index of expansion, n, and
b) The final temperature
1.292, 698K
