commit 82bf86ad65bff5d0c4fc63d06772084672ed3fb8
parent cb41cfc2db3a3cbb14d676398530153ed6189d94
Author: Vincent Forest <vincent.forest@meso-star.com>
Date: Thu, 30 Nov 2017 16:22:54 +0100
Merge remote-tracking branch 'origin/master'
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| M | stardis.html.in | | | 166 | ++++++++++++++++++++++++++++++++++++++++---------------------------------------- |
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@@ -2,39 +2,37 @@
<h1>Stardis - The Monte-Carlo solver for coupled thermal problems</h1>
</header>
-<p>Stardis computes the <b>propagator</b> or the <b>Green function</b> of
-coupled thermal problems under the linear assumption. <b>Coupled</b> refers to
-conductive, convective and radiative transfers . Stardis can deal with complex
-geometries and complex high-frequency external solicitations compared to the
-characteristic time of the system.</p>
-
-<p>Stardis does not compute the whole field of temperature. It computes a
-specific observable such as a temperature at a probe point or the mean
-temperature in a specific volume. And more than the temperature value,
-Stardis gives an evaluation of the propagator. The knowledge of the propagator
-is useful for thermal engineer because it gives some crucial informations to
-analyse the heat transfer in the system. The engineer accesses at some new
-informations like <b> "from where the heat comes at this location ?"</b>.
-Among the possibilies given by the propagator, it can be used as a rapid modele
-without simplifying the geometrical description.</p>
-
-<p>The algorithms implemented in Stardis are inherited from the state of the
-art of the Monte-Carlo method applied to radiative transfers physics (Delatorre
-[1]) combined to the statistical point of view of the conductive heat transfer
-(Kac [2] and Muller [3]). And this theoritical framework can be used in pratice
-to deal with the complex geometries thanks to the state of the art of computer
-graphics which it's at the origin of a disruptive technology in the cinema
-industry (FX and animated movies).</p>
-
-<p>This theoritical framework leads to a <b>statistical point of view</b> of
-the whole heat transfer processess (conductive-convective-radiative) when the
-linear assumption is relevant. And this modele can be solved by a
-<b>Monte-Carlo approach</b> which samples some <b>thermal paths</b>. This type
-of algorithms can be considered as an extension of Monte-Carlo algorithms to
-solve radiative transfer by sampling optical paths. An interesting property of
-this approach is that the resulting algorithms does not rely on a volume mesh
-of the system.</p>
-
+<p>Stardis computes the <b>propagator</b> (aka the <b>Green function</b>) of
+coupled thermal systems under the linear assumption. Here <b>coupled</b>
+refers to conductive, convective and radiative transfers. Stardis can deal
+with complex geometries as well as high-frequency external solicitations
+over very long period of time, relative to the characteristic time of the
+system.</p>
+
+<p>Stardis does not compute temperature fields as a whole. It is designed to
+compute specific observables such as temperatures at probe points / dates or
+the mean temperature in a specific volume / period of time. In addition to
+temperature values, Stardis gives access to an evaluation of the propagator.
+The propagator is of great value for thermicist engineers as it gives some
+crucial information to analyse heat transfers in the system. It helps engineers
+answer questions like <b>"Where from does the heat come at this location?"</b>.
+Propagators seamlessly agregate all the provided geometrical and physical
+information on the system in an unbiased and very-fast statistical model.</p>
+
+<p>Stardis' algorithms are based on state-of-the-art Monte-Carlo method applied
+to radiative transfer physics (Delatorre [1]) combined with conduction's
+statistical formulation (Kac [2] and Muller [3]). Thanks to recent advances in
+computer graphics technology which has already been a game changer in the
+cinema industry (FX and animated movies), this theoritical framework can now
+be practically used on the most geometrically complex models.</p>
+
+<p>Everytime the linear assumption is relevant, this theoritical framework
+allows to encompass all the heat transfer mecanisms (conductive-convective-
+radiative) in an <b>unified statistical model</b>. Such models can be solved by
+a <b>Monte-Carlo approach</b> just by sampling <b>thermal paths</b>. This can
+be seen as an extension of Monte-Carlo algorithms that solve radiative transfer
+by sampling optical paths. A main property of this approach is that the
+resulting algorithms does not rely on a volume mesh of the system.</p>
<h2>An example of propagator use</h2>
@@ -48,17 +46,18 @@ device):</p>
defined by the bottom face tempature, and the environment temperature
(exchange by convection),</li>
<li> the value of interest is the core temperature (semiconductor junction)
- in the red-colored region of the IGBT which also the source of dissipated
- power (see <i>The IGBT model</i> figure),</li>
+ in the red-colored region of the IGBT which is also the source of dissipated
+ power (see figure below),</li>
<li> the propagator has been precomputed using the Stardis Monte-Carlo
- solver from the 3D description of the model and the materials properties
- (see <i>A visualization of the propagator</i> figure),</li>
+ solver from the 3D description of the model and the materials' properties
+ (see figure below),</li>
<li> on request, the propagator is applied to the user-provided temperatures
- and the dissipated power; it acts as a super-fast direct model to compute the
- value of the core temperature,</li>
+ and dissipated power; it acts as a super-fast direct model to compute the
+ value of the core temperature together with its statistical uncertainty
+ (standard error),</li>
<li> as it carries temporal information, the propagator could be used in
- transient computations; in this case the two input temperatures would
- be temporal data.</li>
+ transient computations; in this case the input temperatures and dissipated
+ power would be temporal data.</li>
</ul>
<div class="img" style="width: 50em">
@@ -67,11 +66,12 @@ device):</p>
<img src="IGBT.png" alt="IGBT">
</a>
<div class="caption">
- A simple IGBT example. The points represent the end of a "thermal path"
- when it reaches a boundary condition. The colour of a point indicates the
- time to reach this boundary. This example has been developped in
- collaboration with <a href="https://www.epsilon-alcen.com" >Epsilon-Alcen
- company </a>.
+ <b>A simple IGBT example.</b> Each point represents the end of a "thermal
+ path", where it reaches a boundary condition. The colour of the points
+ indicates the duration (in seconds) of the thermal path, that is the time
+ it tooks for heat to escape the system from the source. This example has
+ been developped in collaboration with
+ <a href="https://www.epsilon-alcen.com">Epsilon-Alcen</a>.
</div>
</div>
@@ -104,24 +104,26 @@ device):</p>
</tr>
</table>
</div>
-<h2>Get Stardis</h2>
-<p>Stardis is not a monolothic software, it's <b>a solver which can be
+<h2>Getting Stardis</h2>
+
+<p>Stardis is not a monolothic software, but <b>a solver which can be
integrated</b> in various thermal engineering simulation toolchain for
designing and optimizing.</p>
-<p>To get Stardis, contact us, we have a versatile commercial offer:</p>
+<p>If you want to get access to Stardis, please contact us. Our commercial
+offers are versatile:</p>
<ul>
- <li> we can provide a Stardis SDK for developpers,</li>
- <li> we can integrate Stardis in your software toolchain,</li>
- <li> we can develop a custom software.</li>
+ <li> we can provide software developpers with a Stardis SDK,</li>
+ <li> we can integrate Stardis in any software toolchain,</li>
+ <li> we can develop custom software from / on top of Stardis.</li>
</ul>
-<p> Stardis is available under many licences. That depends on your status
-(industry or academic) and development constraints (open-source, proprietary,
-...). Of course, these offers can be accompanying with theoretical and practice
-trainings.</p>
-
+<p>Depending on your status (industry or academic) and development constraints
+(open or closed source, ...) Stardis can be made available under the adequate
+license. Of course, both theoritical and software development training is
+proposed on a regular basis as well as on demand to help you master all the
+power of our innovative approach.</p>
<h2>Examples of integration and development</h2>
@@ -136,20 +138,18 @@ trainings.</p>
</div>
</div>
-<p> For its needs of numerical simulations of thermal transfers, EDF R&D
-develops and maintains since several years the SYRTHES software. It solves the
-conductive and radiative transfers in complex geometries and it was designed to
-be integrated in the EDF software toolchain (SALOME). The conductive heat
-transfer is solved by finite elements method and the radiative solver is based
-on radiosity method.</p>
-
-<p> Meso-Star and the SYRTHES developers collaborate since 2015 to integrate
-new features in SYRTHES based the statistical point of view of the thermal
-transfers. Meso-Star accompanies SYRTHES developers to integrate Stardis. The
-objective is not replacing the existing solvers but rather than adding <b>some
-complementary features to facilitate the analysis of numerical
-simulations</b>.</p>
+<p>Mainly to address its own numerical simulation needs on thermal transfer,
+EDF R&D has been developing and maintaining the SYRTHES software for years.
+SYRTHES is dedicated to solve the conductive and radiative transfers in
+complex geometries and was designed to be integrated in the EDF software
+toolchain (SALOME). Inside SYRTHES, the conductive heat transfer solver is a
+finite elements solver and the radiative solver is based on radiosity.</p>
+<p>Meso-Star staff and SYRTHES developers collaborate since 2015 to incorporate
+new features into SYRTHES, based on Stardis and its statistical point of view
+of the thermal transfers. The purpose is not to substitude new solvers to the
+existing ones, but rather to add <b>some complementary features to help
+analysing numerical simulations results</b>.</p>
<h3> PROMES-CNRS - Star-Therm </h3>
@@ -158,24 +158,24 @@ simulations</b>.</p>
<img src="star-therm.png" style="float: relative" alt="Star-Therm">
</a>
<div class="caption">
+ Star_combined conductive–radiative heat transfer
Star-Therm: A code to solve conducto-radiative thermal problems in
complex foams.
</div>
</div>
-
-<p>Meso-Star has developped for the PROMES-CNRS laboratory the Star-Therm code
-based on Stardis solver which solves coupled conducto-radiative thermal
-problems. It was designed to deal with complex geometries such as <b>metallic
-or SiC foams</b>. This type of foams are used as heat exchanger in solar
-<b>concentrated solar process</b> to transfer energy from incoming sunlight
-radiation to a working fluid.</p>
-
-<p>The physical model consists in taking into account coupled thermal radiation
-in vacuum and conduction in opaque solids. Incoming solar energy (radiation) is
-deposited at the surface of a metallic foam, which results in a given boundary
-temperature. Therefore, boundary conditions and initial conditions are known.
-Star-Therm will subsequently have to compute the temperature at any position
+<p>Based on the Stardis solver which solves coupled conductive and radiative
+thermal problems, Meso-Star has developped the Star-Therm code for the
+PROMES-CNRS laboratory. Star-Therm is designed to deal with the geometric
+complexity of <b>metallic or SiC foams</b>. This type of foam is used in the
+design of heat exchangers in concentrated solar processes to transfer the
+energy of the incoming sunlight radiation to a working fluid.</p>
+
+<p>The physical model in Star-Therm considers the incoming thermal radiation
+in vacuum and its coupling with conduction in an opaque solid. The incoming
+solar energy (radiation) is deposited at the surface of the metallic foam,
+which allows to determine a boundary temperature. Knowing boundary conditions
+and initial conditions, Star-Therm can compute the temperature at any position
within the solid.</p>
<h2>References</h2>
