Satellite
model with dual axis articulating solar arrays orbiting earth
(Click
on the picture for animation, requires a video play such as Windows Media Player)
Thermal
Radiation and Orbital Heating Software
RadCAD® is a
thermal radiation analyzer available for use with Thermal Desktop® or stand alone. RadCAD CAD-based program which computers radiation exchange factors, view factors, and orbital heat rates.
An ultra-fast, oct-tree
accelerated Monte-Carlo ray tracing algorithm is used by RadCAD
to compute radiation exchange factors and view factors. Innovations
by C&R Technologies to the ray tracing process have resulted
in an extremely efficient radiation analyzer. A unique progressive
radiosity algorithm has also been incorporated to compute radiation
exchange factors from view factor data. RadCAD has also incorporated
the progressive radiosity algorithm into heating rate calculations,
resulting in even faster performance. Automatic compression and
decompression of internal database files minimizes disk usage.
Powerful
thermal analysis can now be performed using desktop computers, exceeding the performance of most UNIX based workstations. RadCAD uses Monte Carlo Ray Tracing to calculate
form factors, radiation conductors, and heating rates for true conic
surface representations for input into SINDA/FLUINT.
RadCAD is the first radiation analyzer to integrate arbitrary CAD
generated surfaces with familiar parameter-based (TRASYS like) surfaces.
Enhanced Productivity
Analysis
Groups
One
of the many powerful concepts in RadCAD is that of a radiation analysis
group. Any surface, along with active side designations, can be
listed any number of times in different analysis groups. When a
radiation computation (form factors, RADKs, or fluxes) is invoked,
it operates only on the currently active analysis group.
This
provides for speed savings and convenient manipulations of the model.
For example,
consider the simple model depicted here. The radiation on the inside
of the box could be assigned to analysis group "internal," while
the same surfaces (with different active sides) could be assigned
to the analysis group "external." This permits two faster analyses
to be performed, rather than solving the combined case or having
to maintain two separate models.
Analysis
groups have other uses as well. For example, they enable the user
to maintain alternate cases and alternate components within the
same geometric model. They are also one of the bases for creating
selection sets for model verification and for post processing.
Articulated Geometry
Articulators are modeling objects that can be used to change the position or model geometry. Thermal Desktop has two types of articulators: assemblies and trackers. Assemblies can translate and rotate modeling objects (including other articulators) or groups of modeling objects. The translation and rotation of an assembly is user defined, but can be defined using complex mathematical expressions. Trackers are a special type of articulator that rotates model objects based on the relative position of orbital features (planet, Sun, or star). Trackers are useful for pointing solar arrays, radiators, etc. Trackers have a single degree of freedom, but can be nested within other trackers and/or assemblies for unlimited degrees of freedom.
Property
Databases and Aliases
Surface
optical properties (solar absorptivity, infrared emissivity, degree
of specularity, etc.) can be input as numbers, or indirectly as
user-defined names ("white paint," "aft canister," etc.). These
names can refer to a property identified in a user-controlled database,
or they can refer to an alias. Property aliases enable the user
to reassign coatings or materials at a high level with little work.
For example, using the alias manager as shown here, the user can
reassign the optical properties of all components designated "radiator"
to be "white paint."
Together
with an ability to quickly swap databases (i.e., to change the definition
of "white paint" with alternate white paints), aliases provide the
user with a quick means of performing what-if analyses, comparing
designs, events, and levels of degradation.
Correspondence
Trees
Another
Thermal Desktop innovation is a tree-style manager for handling
the optional correspondence (mapping) between Thermal Desktop surfaces
and SINDA nodes. (Correspondence data may be used to collect predictions
for one or more nodes together before being output for SINDA.) This
intuitive form (as shown here) provides fast visual access to this
data, which is difficult to maintain in older analyzers.
Correspondence
is also automatically maintained when postprocessing SINDA results
on the Thermal Desktop drawing (an example of which is shown on
the first page).
Cumulative
Accuracy
RadCAD
allows users to accumulate accuracy by choosing to extend a ray
tracing analysis farther after having viewed intermediate results.
Previous RADK or heating rate solutions may be continued for added
accuracy without losing prior answers. The code automatically checks
to make sure that no changes have been made that render the previous
analysis invalid as a starting point
Importing/Exporting
As an
aid to existing TRASYS users, Thermal Desktop can directly import/export
TRASYS geometry and property information (such as the model shown
here), retaining a knowledge of BCS organization on different layers,
and which can be used as selection sets to help a user better exploit
unique new Thermal Desktop features. Thermal Desktop can also import
NEVADA and TSS models.
The following
capabilities have been added or expanded:
General:
AutoCAD® 2010 compatibility.
A parabolic trough Thermal Desktop surface has been added.
A new and improved EZXY plotter is used for X-Y plots of data vs. time.
Register names in SINDA/FLUINT can now be 32 characters long. This means that symbol names can be 32 characters long even if the symbol is used to create a register. This also affects the heater append strings which were previously limited to 6 characters; they are now limited to 30 characters.
Measures feature allows thermocouple devices to be added. Thermocouples interpolate the temperature of an object based on the relative location to nodes.
Three commands have been added to Thermal > Utilities menu: toggle undo recording; save SINDA/FLUINT work directory; and search for text.
Symbols, Case Sets, Orbits, Logic Objects, property aliases, analysis groups, and submodels (with comments) can now be imported directly from a Thermal Desktop DWG file without first being explicitly exported.
Model Browser has been enhanced with: list by non-graphical items (e.g. - case sets, orbits, logic objects, optical properties and thermophysical properties), layers, and measures; a repositionable field separator; indications for disabled objects and network element logic; conductor and logic submodel names for subordinate items; symbol group names in list by symbols; contactor and TEC From and To areas; and rightclick contextual menus.
Case Set Manager has been enhanced with: tree-based Case Set groups; drag-and-drop capability for reorganization; and right-click contextual menus.
Symbol manager now has Find command to help locate symbols.
Logic Manager has been enhanced with: tree-based organization with groups; dragand- drop functionality; equations of motion; and time-step limits for array interpolation to avoid overstepping array points.
Symbol usage is now checked for usage consistency. The user will be notified if symbols are used in fields or expression editors that have different units.
Thermal Desktop:
Thermal submodel names up to 32 characters are now allowed. Many forms have changed to account for this. Submodel definition allows comments.
Thermophysical properties manager has been enhanced with: resizable columns; sorting by material name or property value; and interpolation/extrapolation of temperature dependent properties to room temperature.
Save files can be queried for: minimum and maximum temperatures and register values; heater performance; heat flow between user-specified sets of nodes; sink temperatures and corresponding conductors for subsets of nodes. Save file data can be written to text through the post processing menu.
User-defined nodes can be provided a mass or a volume when material option is chosen.
Heater power can be input as a flux.
Warnings are provided when contactor From area is greater than the To area. This usually indicates a problem. Contactor form allows quick switching of From and To sets.
NASTRAN importer has been expanded to import CTRIA6, CTRIA6*, CQUAD8, and CQUAD8* elements as well as QVOL boundary conditions.
Solid-solid fusion capability has been added.
User has been provided more control over contactor restarts.
GLOBAL logic designator has been added to SINDA. The GLOBAL logic is called regardless of built submodels and is used as default for output calls.
RadCAD:
Optical properties manager has been enhanced with: resizable columns; sorting by material name or property value; and interpolation/extrapolation of temperature dependent properties to room temperature.
Free molecular heating has been enhanced to reference basic and Keplerian orbits with tracking and velocity vector calculation.
Heating rates can be computed using albedo specified as a function of latitude and longitude. The calculations use a rotating planet based on the sidereal period.
Heating rates can be computed using planetshine specified as function of latitude and longitude. The planet is not rotated with time for these calculations. The data may be input as a temperature or a flux, and may be input relative to the planet’s latitude and longitude coordinate system, or a coordinate system constructed about the sub-solar point.
Diffuse Sky Solar and Diffuse Sky IR sources have been added to the Planetary heating environment.
Latitude and longitude dependent albedo and planetshine data can be displayed in color on the planet when in orbit mode. An orbit data color bar is displayed, and may be edited similarly to other post processing color bars.
Output and case set names can be added to RadCAD dataset name.
An optical property summary has been added to the *.k and *.hra files.
FloCAD:
Fluid submodel names up to 32 characters are now allowed. Many forms have changed to account for this.
FloCAD MACRO algorithm has been improved to work with SINDA/FLUINT improvements.
Twin ties are now supported.
Pipes have been improved to support: twin lumps and twin ties; changes to subdivisions in multi-edit mode; specification of length subdivision using a symbol; and two materials in the pipe wall (divided radially).
Friction factors can be augmented from heat transfer and heat transfer multipliers can be based on friction, curves and entrances.
Minimum System Requirements
XP Pro (SP2 or newer), Vista Pro or Home, Windows 7
AutoCAD
32 Bit Version: 2004, 2005, 2006, 2007, 2008, 2009, 2010 or 2011
As of version 5.4 to be released in the first quarter of 2011, versions 2004, 2005 and 2006 will no longer be supported.
64 Bit Version: AutoCAD 2008, 2009, 2010 or 2011
Memory: 1 GB
Minimum for XP, 2 GB for Vista or Windows 7
Display resolution:
1024x768 minimum, 1280x1024 or finer recommended
