A quantity of air (γ = 1.40) expands adiabatically from an
initial pressure of 2 atm...
A quantity of air (γ = 1.40) expands adiabatically from an
initial pressure of 2 atm and volume of 2 L at temperature 20 ° C
to twice its original volume. Find:
An adiabatic gas turbine uses air to produce work. Air expands
adiabatically from 600 kPa and 287 C to 90 kPa and 67 C. Take
specific heats at room temperature (300 K). a) Find the isentropic
efficiency of the turbine. b) Find the work produced by the turbine
for a mass flow rate of 2.5 kg/s. c) If the mass flow rate of air
is again 2.5 kg/s, find the entropy generation under steady
conditions
3.19 A gas with adiabatic exponent γ is compressed adiabatically
from an initial state (Pi, Vi) to final state (Pf, Vf). (a) Show
that the work done in this process is
W=((ViPi)/y-1)*[(Vi/Vf)^(y-1) -1]
(b) Evaluate the result numerically for one mole of helium gas
initially
at P = 1.0 atm and T = 300 K compressed to half its initial
volume.
(c) Compute the work done in an isothermal compression from the
same
initial point to half the initial volume....
Air at 480Kpa is expanded adiabatically to a pressure of 94Kpa.
It is then heated at constant volume until it again attains its
temperature, when the pressure is found to be 150KPa. it then
undergoes an isothermal compression to return the air to its
original state. Using this information sketch the p-v diagram and
calculate the value of γ. If the initial temperature of air is
190oC determine the work done per kg during the
adiabatic expansion and teh isotherman...
A gas turbine expands air adiabatically at 1000 kPa
and 550 ⁰C to 120 kPa and 130⁰C. Air enters the
turbine through a 0.25 m
2 opening with an aveage velocity of 45 m/s, and exhausts through a
1 m2
opening. Assume the air is ideal gas with constant specific heats.
Take the constant pressure specific
heat and gas constant of air as Cp= 1.05 kJ/(kg K) and R=0.287
kJ/(kg K), respectively. Determine;
(a) the mass flow rate of air...
15 g of nitrogen gas at STP are adiabatically compressed to a
pressure of 21 atm .
What is the final temperature of the gas?
What is the work done on the gas?
What is the heat input to the gas?
What is the compression ratio Vmax/Vmin?
500 kmol/h of an air stream at a pressure of 2 atm is to be
heated from 15 celsius to 90 celsius in a heat exchanger with 600
kPa steam condensing in the shell side of the heat exchanger. Steam
enters the exchanger as a saturated vapor and leaves as a saturated
liquid.
A) How much steam would be required if a conventional heat
exchanger were used? what is the total entropy change during this
process?
B) How much steam...
Air that occupies a volume of 0.142m3 at a gauge pressure of
103kPa, expands isothermally to zero gauge pressure and then is
cooled to constant pressure until it reaches its initial volume.
Calculate the work done on the gas.
Answer: -5.74 kJ
2.50 mole of perfect gas at 0°C is expanded from an initial
pressure of 5.00 atm to a final pressure of 1.00 atm against a
constant external pressure of 1.00 atm. (a) isothermally and (b)
adiabatically. (1) Calculate the values of q, w, DU, DH, DS, DSsur
and DStot for (a) and (b) (2) Draw p -V diagram to represent these
two different paths.