Skip to content

Commit

Permalink
[web/THM] Water freezing volumetric expansion
Browse files Browse the repository at this point in the history
Documentation of the volumetric expansion due to water-to-ice
phase change test.
  • Loading branch information
Tymofiy Gerasimov authored and endJunction committed Aug 31, 2023
1 parent 9d6f6f4 commit 0ab7091
Show file tree
Hide file tree
Showing 5 changed files with 119 additions and 0 deletions.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Original file line number Diff line number Diff line change
@@ -0,0 +1,119 @@
+++
author = "Tymofiy Gerasimov, Dmitri Naumov"
date = "2023-29-8"
title = "Checking the volumetric expansion due to water-to-ice phase change"
project = ["ThermoHydroMechanics/9percentWaterFreezingExpansion/UnitSquare.prj"]
image = "Ice_strain_setup.png"
+++

{{< data-link >}}

## Problem description

The aim of this benchmark is to verify that our THM model is capable of
simulating the 9% volumetric expansion during the liquid-to-ice phase
transition.
This must be captured by the $\boldsymbol\sigma_\mathrm{I}$-stress component
of the formulation

$$
\begin{align*}
\boldsymbol\sigma\_\mathrm{SI} :=&\boldsymbol\sigma\_\mathrm{S}+ \boldsymbol\sigma\_\mathrm{I} \\\\\\
=&\mathbb{C}\_\mathrm{S}:\left(\boldsymbol\varepsilon-\alpha^\mathrm{S}\_T (T-T\_0){\bf I}\right) \\\\\\
+&\phi S\_\mathrm{I}(T) \mathbb{C}\_\mathrm{IR}:
\left(\boldsymbol\varepsilon-\boldsymbol\varepsilon\_\mathrm{S0}
- \alpha^\mathrm{I}\_T (T-T\_\mathrm{m}){\bf I}
- \alpha\_{\phi\_\mathrm{I}} S\_\mathrm{I}(T){\bf I}
\right),
\end{align*}
$$

where $\mathbb{C}\_\mathrm{S}$ and $\mathbb{C}\_\mathrm{IR}$ are the forth order
elasticity tensors of solid matrix and ice phase, respectively,
$\boldsymbol\varepsilon$ is the total strain, $\alpha^\mathrm{S}\_T$ and
$\alpha^\mathrm{I}\_T$ are the linear thermal expansivities of solid and
ice phases, respectively, $\phi$ is the porosity,
$\alpha_{\phi_\mathrm{I}}=0.03$ is the linear expansion coefficient due
to water-to-ice phase change and, finally, $S\_\mathrm{I}(T)$ is the
regularized ice phase indicator function ($S\_\mathrm{I}\rightarrow 1$ is
ice, and $\rightarrow 0$ is liquid water).
Then the material properties in the benchmark are to be chosen such that
$E_\mathrm{S}\ll E_\mathrm{IR}$.
In this way, and also with the absence of mechanical loading, the
deformation of a specimen --- with $\alpha_{\phi_\mathrm{I}}$ being the
strain increase in each space direction --- will occur solely due to liquid freezing.

The material properties in the benchmark are to be chosen such that the Young's
modulus of solid is smaller than that of ice, i.e. $E_\mathrm{S}\ll E_\mathrm{IR}$.
In this way, and also with the absence of mechanical loading, the deformation of
a specimen with $\alpha_{\phi_\mathrm{I}}=0.03$ being the strain increase in
each space direction will occur solely due to liquid freezing.

For the geometric setup we consider a fully saturated cylindrical column whose
bottom edge is supported by a rigid foundation.
Using the axis symmetry the problem is reduced from 3 to 2 dimensions with a
simple (square) computational domain and related (Dirichlet) boundary
conditions, see Figure 1, where an expected deformed configuration is also
sketched.
Again, we apply no mechanical loading to the specimen, whereas the thermal
loading is presented by temperature evolution over time.
The temperature $T$ is prescribed as a constant in $\Omega$ at each time step
and decays linearly from $+4\\,^\circ \text{C}$ to $-4\\,^\circ \mathrm{C}$
during one hour term, as depicted in Figure 2, left.

{{< img src="Ice_strain_setup.png" >}}
**Figure 1:** Fully saturated column expansion due to water-to-ice phase
transition: geometry (on the left) and the 2d computational setup along with the
expected deformed configuration (on the right).

Material data used in the computations are presented in Table 1.
No liquid phase parameters are present since we don't solve for the hydraulic
equation and the temperature field is prescribed.
The two parameters that are varied are the time step increment $\Delta t$ (also
denoted as $\mathrm{dt}$ in the corresponding captions) and the parameter $k>0$
in the Sigmoid function $S_\mathrm{I}$ which governs the "thickness" of a
temperature-related phase transition zone.
More specifically, we take $\Delta t\in\\{10\\,\mathrm{s}, 30\\,\mathrm{s},
60\\,\mathrm{s}\\}$ and $k\in\\{2,5,20,50\\}$.
$\Omega$ is discretized with only one element (which is possible/allowed here
since the setup implies no freezing front propagation within the domain).
Finally, the FE approximation of the components of strain tensor
$\boldsymbol\varepsilon$ uses the $Q_1$-quadrilaterals.

{{< img src="Ice_strain_MaterTable.png" >}}
**Table:** Material properties and parameters.

## Simulation results and analysis

Figure 2, right, depicts evolution of strain tensor components
$\varepsilon_{xx}$, $\varepsilon_{yy}$, $\varepsilon_{zz}$ computed for the
fixed parametric pair $(\Delta t, k)=(60\\,\mathrm{s}, 20)$.
All three strains behave identically and, more importantly, as expected, they
transit from 0 to the reference magnitude of 0.03 during the freezing, in
accordance to the term $\alpha_{\phi_\mathrm{I}}S_\mathrm{I}(T)$.

{{< img src="Ice_strain_3strains.png" >}}
**Figure 2:** The prescribed temperature loading applied to the specimen (on the
left) and the induced strains evolution due to phase change (on the right).

Figure 3 details the parametric studies for the computed $\varepsilon_{xx}$: on
the left plot, for the fixed time increment, one observes that for any
considered $k$ the corresponding strains transit up to the required value 0.03
and, as also expected, the increase of the parameter yields a steeper and more
localized transition zone, almost mimicking the Heaviside-like behaviour at
$k=50$.
It is interesting to observe a slight downward deviation of $\varepsilon_{xx}$
from the horizontal reference value in the post-freezing time range (that is,
when the prescribed temperature keeps on decreasing from $T_\mathrm{m}$ to
$-4\\,^\circ\mathrm{C}$).
This behaviour is physical and implies the ice contraction in such temperature
range.
The right plot of Figure 3 presents the evolution of
$\varepsilon_{xx}$---specifically, the required transit during the phase
change---for a fixed steepness-related parameter $k$ and varying time step size.
All three computational results seem identical.

{{< img src="Ice_strain_dt-k.png" >}}
**Figure 3:** Parametric studies for the computed volumetric strain expansion in
dependence on the time step size and parameter $k$ in $S_\mathrm{I}(T)$ that governs
the thickness of the phase transition zone.

0 comments on commit 0ab7091

Please sign in to comment.