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Add Van der Waals equation of state #11359
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""" | ||||||
The van der Waals equation, named for its originator, | ||||||
the Dutch physicist Johannes Diderik van der Waals, | ||||||
is an equation of state that extends the ideal gas | ||||||
law to include the non-zero size | ||||||
of gas molecules and the interactions between them | ||||||
(both of which depend on the specific substance). | ||||||
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As a result the equation is able to model the phase | ||||||
change from liquid to gas, and vice versa. | ||||||
It also produces simple analytic expressions for the | ||||||
properties of real substances that shed light on their | ||||||
behavior. | ||||||
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( Description was taken from https://en.wikipedia.org/wiki/Van_der_Waals_equation ) | ||||||
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--------------------- | ||||||
| (p+a/V^2)(V-bv)=vRT | | ||||||
--------------------- | ||||||
! p - Pressure (Pa) | ||||||
! V - Volume (m^3) | ||||||
! v - Amount of gas (mol) | ||||||
! R - Universal gas constant | ||||||
! T Absolute temperature (K) | ||||||
! a, b - Parameters | ||||||
""" | ||||||
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R = 8.314462618 | ||||||
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# Taken from https://ru.wikipedia.org/wiki/Уравнение_Ван-дер-Ваальса | ||||||
CONSTANTS = { | ||||||
"nitrogen": {"a": 0.1370, "b": 38.7e-6}, | ||||||
"ammonia": {"a": 0.4225, "b": 37.1e-6}, | ||||||
"argon": {"a": 0.1355, "b": 32.0e-6}, | ||||||
"oxygen": {"a": 0.1382, "b": 31.9e-6}, | ||||||
} | ||||||
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def system_pressure( | ||||||
quantity: float, temperature: float, volume: float, a: float, b: float | ||||||
) -> float: | ||||||
""" | ||||||
Gets the system pressure from other 2 parameters | ||||||
--------------------- | ||||||
| p=(vRT)/(V-bv)-a/V^2 | | ||||||
--------------------- | ||||||
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>>> system_pressure(1, 300, 1, 0.1382, 31.9e-6) | ||||||
2494.2801573455995 | ||||||
>>> system_pressure(1, 100, 1, 0.1382, 31.9e-6) | ||||||
831.3345857818664 | ||||||
>>> system_pressure(1, 300, -1, 0.1382, 31.9e-6) | ||||||
Traceback (most recent call last): | ||||||
... | ||||||
ValueError: Please provide the positive values | ||||||
""" | ||||||
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if temperature < 0 or volume < 0: | ||||||
raise ValueError("Please provide the positive values") | ||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more.
Suggested change
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Please add a test for both values being zero. |
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return (quantity * R * temperature) / (volume - quantity * b) - a / (volume**2) | ||||||
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def system_temperature( | ||||||
quantity: float, pressure: float, volume: float, a: float, b: float | ||||||
) -> float: | ||||||
""" | ||||||
Gets the system temperature from other 2 parameters | ||||||
--------------------- | ||||||
| T = 1/(vR)*(p+a/V^2)(V-bv) | | ||||||
--------------------- | ||||||
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>>> system_temperature(1, 300, 1, 0.1382, 31.9e-6) | ||||||
36.09717661628195 | ||||||
>>> system_temperature(1, 100, 1, 0.1382, 31.9e-6) | ||||||
12.04347294491859 | ||||||
>>> system_temperature(1, 300, -1, 0.1382, 31.9e-6) | ||||||
Traceback (most recent call last): | ||||||
... | ||||||
ValueError: Please provide the positive values | ||||||
""" | ||||||
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if pressure < 0 or volume < 0: | ||||||
raise ValueError("Please provide the positive values") | ||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Non-negative |
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return 1 / (quantity * R) * (pressure + a / volume**2) * (volume - quantity * b) | ||||||
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def critical_temperature(a: float, b: float) -> float: | ||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Single letter variable names went out of style in the 1970’s. |
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""" | ||||||
Calculate the critical temperature from two parameters for each gas | ||||||
--------------------- | ||||||
| T_c=8a/(27bR) | | ||||||
--------------------- | ||||||
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>>> critical_temperature(0.1382, 31.9e-6) | ||||||
154.3865270378366 | ||||||
""" | ||||||
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return 8 * a / (27 * b * R) | ||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Please replace b & R with self-documentating names |
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def critical_volume(b: float) -> float: | ||||||
""" | ||||||
Calculate the critical volume from one parameter for each gas | ||||||
--------------------- | ||||||
| V_c=3b | | ||||||
--------------------- | ||||||
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>>> critical_volume(31.9e-6) | ||||||
9.570000000000001e-05 | ||||||
""" | ||||||
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return 3 * b | ||||||
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def critical_pressure(a: float, b: float) -> float: | ||||||
""" | ||||||
Calculate the critical pressure from two parameters for each gas | ||||||
--------------------- | ||||||
| p_c=a/(27b^2) | | ||||||
--------------------- | ||||||
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>>> critical_pressure(0.1382, 31.9e-6) | ||||||
5029941.253052267 | ||||||
""" | ||||||
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return a / (27 * b**2) | ||||||
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def critical_coefficient(a: float, b: float) -> float: | ||||||
""" | ||||||
Calculate the critical coefficient from two parameters for each gas | ||||||
--------------------- | ||||||
| k_c=(R*T_c)/(p_c*V_c) | | ||||||
--------------------- | ||||||
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>>> critical_coefficient(0.1382, 31.9e-6) | ||||||
2.6666666666666665 | ||||||
""" | ||||||
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return ( | ||||||
R * critical_temperature(a, b) / (critical_pressure(a, b) * critical_volume(b)) | ||||||
) | ||||||
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def given_volume(volume: float, b: float) -> float: | ||||||
""" | ||||||
Calculate the given volume from one parameter for each gas and volume | ||||||
--------------------- | ||||||
| φ = V / V_c | | ||||||
--------------------- | ||||||
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>>> given_volume(1, 31.9e-6) | ||||||
10449.32079414838 | ||||||
""" | ||||||
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return volume / critical_volume(b) | ||||||
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def given_pressure(pressure: float, a: float, b: float) -> float: | ||||||
""" | ||||||
Calculate the given pressure from two parameters for each gas and pressure | ||||||
--------------------- | ||||||
| π = p / p_c | | ||||||
--------------------- | ||||||
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>>> given_pressure(1, 0.1382, 31.9e-6) | ||||||
1.9880947901591899e-07 | ||||||
""" | ||||||
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return pressure / critical_pressure(a, b) | ||||||
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def given_temperature(temperature: float, a: float, b: float) -> float: | ||||||
""" | ||||||
Calculate the given temperature from two parameters for each gas and temperature | ||||||
--------------------- | ||||||
| τ = T / T_c | | ||||||
--------------------- | ||||||
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>>> given_temperature(1, 0.1382, 31.9e-6) | ||||||
0.006477249143346057 | ||||||
""" | ||||||
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return temperature / critical_temperature(a, b) | ||||||
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if __name__ == "__main__": | ||||||
from doctest import testmod | ||||||
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testmod() |
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Please replace
a
andb
with self-documentating variable names.There was a problem hiding this comment.
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What happens when quantity is zero? When quantity is negative?