Fluids

Fluids are classes representing different type of working fluids, which can potentially have properties that depend on temperature.

Fluid

The class Fluid provides a blueprint for all fluid classes and defines the main methods that are used during simulations. The following table shows a summary of the fluid properties that need to be implemented and the relevant method:

Name	Symbol	Method	Unit
Specific heat capacity	\(c_p\)	`get_cp()`	\(J/(kg \cdot K)\)
Density	\(\rho\)	`get_rho()`	\(kg/m^3\)
Dynamic viscosity	\(\mu\)	`get_mu()`	\(Pa \cdot s\)
Thermal conductivity	\(k\)	`get_k()`	\(W/(m \cdot K)\)

ConstantWater

The class ConstantWater represents water with constant properties:

Symbol	Documentation	Default	Unit
\(c_p\)	`CP_WATER`	`4182.0`	\(J/(kg \cdot K)\)
\(\rho\)	`RHO_WATER`	`990.0`	\(kg/m^3\)
\(\mu\)	`MU_WATER`	`0.0004`	\(Pa \cdot s\)
\(k\)	`K_WATER`	`0.598`	\(W/(m \cdot K)\)

Example usage:

>>> from pydhn.fluids import ConstantWater
>>> fluid = ConstantWater()
>>> # Print the fluid specific heat capacity at 60°C
>>> print(fluid.get_cp(t=60))
4182.0
>>> # Print the fluid density at 40°C
>>> print(fluid.get_rho(t=40))
990.0

Water

The class Water models water with variable properties. The relationships between the fluid properties and its temperature are taken from [CzWo98]. The range of validity is 0-150°C.

Example usage:

>>> from pydhn.fluids import Water
>>> fluid = Water()
>>> # Print the fluid specific heat capacity at 60°C
>>> print(fluid.get_cp(t=60))
4184.625980441447
>>> # Print the fluid specific heat capacity at 40°C
>>> print(fluid.get_cp(t=40))
4178.8227047312685