a 4l pressure cooker has an operating pressure of 175 kpa
Answers
An empty bottle is surrounded by atmospheric air. A valve is undone, and air is permitted to fill the bottle. The amount of heat transfer through the wall of the bottle when the thermal and mechanical balance is established and the quantity of bodies being destroyed is determined.
Conception 1 This is an unstable process as the situation within the device is changing during the process, but they can be analyzed as a common flow process because the fluid conditions on the inlet remain constant. 2 air is an ideal gas. Kinetic and potential energy are negligible. 4 There is no working conversation in it. 5 The direction of heat transfer is for air in the bottle .
Properties air gas stability is 0.287 KPAMM / kg .
Analysis We take the bottle as a system, which has control volume since crossing the border control. Noteing that the astral energy of the flowing and non-flowing fluid is shown by enthusiastic H and the inner energy respectively, the mass and energy balance can be expressed
mass balance:
energy balance:
Minute mout msystem
14,243
Mi m2
Esystem
14,243
(Since mout minitial 0)
Net energy transfer by heat, work, and mass
Change to internal, dynamic, potential, etc.
QMile Hi m2u2
A mixture of two balances:
QN M2U2 Hi
where
MP2V
2 RT
100 kpa 0.012 m3
0.287 kpa m3 / kg290 00144
In = (0.0144 kg) (206.91 - 29.16) KJ / kg = - 1.2 kJ quote = 1.2 kJ
Note that the negative signal for heat transfer indicates that the estimated direction is wrong. Therefore, we reversed the direction.
Entropy generated during this process is determined by applying an entropy balance on an extended system, which consists of bottle and its immediate surroundings so that the range of the extended system is around the temperature at all times. This can be expressed as an entropy balance
Sin south
Sgen
{
s
system
14,243
Net Entropy Transfer by Heat and Mass
Entropy generation
14,243
Change
In entropy
Mile sea
outside
Tb, in
Sgen
stank
M2S2
m1s1
0
M2S2
Therefore, there is total entropy generated during this process.
Sgen
Mile sea
M2S2
M2 out
s2
S. Quote Quote 1.2 KJ 0.00415 KJ / K
Tb, out
Tb, out
Tsurr
Of 290
The bodies that are destroyed during a process can be destroyed from the excise balance or directly defined by X. T. Sgen,
X eliminated
T. Sgen 290k* 0.00415 kJ / K = 1.2 kJ