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If you can't find the information you are looking for, please e-mail it to us now.
Do I need to purchase the entire suite of C&R tools? Although many applications don't require the entire product suite, many users still purchase the entire suite for versatility. Our Product Selection Matrix and connectivity page show the relationship of all the C&R products. If your application requires a CAD interface for geometrical modeling, you will need Thermal Desktop and Sinda/Fluint as a minimum. If you do not need the CAD based interface or you are working on a more abstract fluid application, you will most likely require SinapsPlus and Sinda/Fluint. Both Thermal Desktop and SinapsPlus generate Sinda/Fluint input files and require Sinda/Fluint to be installed on the machine for model execution. The only exception is using SinapsPlus prebuilts. Prebuilts do not require the purchase and installation of Sinda/Fluint to run the basic model. If the user desires to modify the model network or control, then Sinda/Fluint is required.
Do I need AutoCAD to run Thermal Desktop? Yes. Thermal Desktop is available as a product bundled with AutoCAD if you don't already have AutoCAD, or it is available as a plug-in to AutoCAD if you do already have a licensed version of AutoCAD. Thermal Desktop is integrated with AutoCAD. The integration with AutoCAD gives Thermal Desktop all the CAD capabilities such as snap on model building, scaling, mirroring, extrude, and revolve that allow users to quickly build models.
What is the relevancy of the various file suffixes for the product suite? The table below summarizes all the files used or generated by the C&R
Where do I place the license file? The table below summarizes where your license file should be placed for each product. All installations on NT systems, must be performed by someone with administrative privileges.
Sinda/Fluint Installation and Licensing Incorrect license file or location If the following
messages appear at the end of the output file: Make sure the license file is installed in the directory named "bin" where you installed Sinda/Fluint. Make sure the key (if required for your license) is properly connected to the parallel port of your machine. If you are upgrading your current version, you will need to obtain a new license file from C&R Technologies.
Sinda/Fluint Usage FAQ's How to make sure all of the output was been written into an output file when the program terminates abnormally? You need to flush the buffer: Under Compaq (aka DEC) and the "no compiler required" version, simply
Note that SAVE files (of all forms: RESAVE, CRASH etc.) are always flushed to be safe and to allow you to monitor progress in EZXY while running (via refresh).
Why do I get an error stating that it can't find an included file that exists? The program default is to look for all files in the same directory as the input deck (the local directory). If the file is located elsewhere, you need to provide the fully qualified path name. As an alternative you can specify a path.txt file in your local directory or in the /bin directory of the Sinda/Fluint installation directory. Note this option only applies if you use the INSERT command and does not apply if you use the INCLUDE command. The path.txt file can contain a list of up to 10 paths for SINDA/FLUINT to search. SINDA/FLUINT will first look in the working directory for "INSERT"ed files. If the file is not found it will look for path.txt in the local directory and search each specified path. If paths.txt is not found in the working directory it next moves to the SINDA/FLUINT installation directory to look for it. If you have a paths.txt file in both the local directory and the SINDA/FLUINT installation directory, only the local version will be used. This option is especially useful for fluid property files by allowing a user to maintain all their fluid property databases in one location.
Can you clarify stagnation versus static conditions in FLUINT and how best to use them (LSTAT=STAG vs. NORM)? This is often an area of confusion for FLUINT users. By default, SINDA/FLUINT assumes static pressures and temperatures in fluid flow unless otherwise specified by the user. The static pressure is the pressure the fluid feels as it moves. It is what would be measured by an observer moving with the fluid particles. Historically (prior to version 4.4) FLUINT only used static pressures throughout the modeling process. Static pressures are the only real way to handle thermodynamics and other compressible flow effects. Total pressure is primarily used for "energy book-keeping" in steady incompressible flows although there are other uses: some pump curves are based on totals, etc. With the release of version SINDA/FLUINT 4.4 a new option was provided to allow users to specify a lump to represent stagnation, or total pressure and temperature (LSTAT = STAG). By specifying LSTAT=STAG the user identifies the fluid in the lump to be stagnant or not moving. The stagnation pressure is the sum of the static pressure and the velocity, or dynamic, pressure (the rho*vel^2/2 term in Bernoulli's equation for an incompressible fluid). It is the pressure that would be obtained if the fluid were decelerated isentropically to zero velocity, or the static state. The stagnation temperature is the temperature that a fluid will attain when decelerated adiabatically (no heat transfer) to zero velocity from static conditions. If a lump is specified by the user as stagnation, SINDA/FLUINT automatically adds an internal loss, equivalent to a K-factor of 1.0, to all paths with flow exiting the lump, accounting for acceleration of the fluid out of the lump from a negligible velocity to that of the moving fluid. This acceleration process will decrease the pressure of the fluid from stagnation to static across the path. This hidden K-factor is not an entrance loss; it accounts for the fact that the fluid must get moving (momentum not energy effect). Losses due to sharp edges etc still must be added by the user. This hidden term applies to any path with a K-factor (including tubes and STUBE connectors), and is meaningless for devices without a K-factor (CAPIL, MFRSET, VPUMP, etc.). Setting the LSTAT flag to STAG affects three areas of the code: kinetic energy, choking, and momentum (accelerations). 1. Kinetic energies are zero in flow originating from a stagnant lump. There is no kinetic energy associated with a lump, so this only affects outflowing paths: treat the upstream temperature and pressure as total or stagnation. The STAG option turns off kinetic energy out of the lump, perhaps lowering the temperature of downstream static lumps (if they are not plena) since part of the energy is converted from thermal to kinetic. For high speed flow out of a plenum, which is otherwise a static state, this can be a big difference. 2. Flow must always be expanded from zero velocity for critical flow rate (choking) calculations, even if AF=AFTH in outflowing paths. And if AFTH<AF, the flow is expanded from zero velocity, not from the upstream velocity based on the current path flowrate. Flow is more likely to be choked if flowing out of a stagnant lump than a static one. 3. Flow must be accelerated from zero into any outflowing paths. Therefore, a recoverable loss equivalent to a K-factor of 1.0 is added automatically to any outflowing loss-type paths (STUBE, tube, LOSS, valves, etc.), but not to pump-type paths (MFRSET, PUMP, etc.). Note that this recoverable loss disappears if the flow reverses direction. Unless you have high speeds or choking at the entrance (or out of a stagnant point), most models will be most influenced by #3: an accelerational term in the momentum equations. Although the LSTAT=STAG option can be used with any lump, it is often most appropriate for plena if they represent a large reservoir, ambient, etc. and do not simply represent a constant pressure at a cross section within a pipeline. Large volume tanks and plena do not imply "wide flow area" nor "low velocity" since flow area and velocity are only attributes of paths, not lumps .Therefore, to signal to the code that the flow has negligible velocity coming out of a certain lump, you can state LSTAT=STAG. Do not use LSTAT=STAG just to "find the current stagnation pressure" of a lump through which velocity is not zero. LSTAT=STAG has modeling repercussions (listed above), and its election will change the predictions.
How can I find the nodes with the smallest CSG or rank the nodes in a submodel from smallest CSG to largest? In the model, call the subroutine NODTAB. You can call this for all submodels or for just one submodel. Run the model. then look at the output file for the NODTAB results. Copy the results of NODTAB to a text file (using a simple text editor like Notepad or Wordpad). Save the text file.Then open Excel and choose Data>>Get External Data>>Import Text File. Browse to your text file that you saved with the NODTAB data. Use Fixed Width. Next, Next, Finish, and OK. You are done. Now you can sort in Excel to rank the nodes.
How can I diagnose what is causing my model not to converge? When your model will not converge to a steady state solution, the output file will usually be the first place to look for the cause. In the example below you can see the calculated DRLXCC and ARLXCC are both greater than the allowed values, resulting in the non-convergence. The non-convergence may be resolved simply by increasing the maximum loop count NLOOPS.
The non-convergence may have other causes such as energy imbalance or failure to meet maximum allowable changes in a fluid model. Inspection of the output header for the fluid submodel may contain information regarding the non-convergence cause. In some cases, the non-convergence may be caused by instabilities rather than insufficient iterations. Graphical inspection of the model parameters each iteration can be very helpful in diagnosing stability problems and their cause. Setting the output control parameters ITEROT (for thermal submodels) or ITROTF (fluid submodels) to the following expression, allows you to plot any parameter saved to the save file for the last 50 iterations.
I want to make several user output files but SINDA/FLUINT only lets me define two (USER1 and USER2). How do I expand to three or four user files? This can be accomplished through the subroutine USRFIL and USRFIL2. Simply define the "unit number" as an integer variable through register data. Then use the USRFIL subroutine to open the file and return the unit number as the register value. The unit number can then be used in subsequent read and write statements. Please refer to the SINDA/FLUINT User's Manual information on the subroutines USRFIL and USRFIL2 for more information and guidance. HEADER REGISTER DATA HEADER OUTPUT CALLS, MYMOD
What are the system requirements for Thermal Desktop? Please refer to the system requirements page for this information. Note that Thermal Desktop runs significantly faster with more memory and disk space than the stated in these minimum requirements.
How do I install Thermal Desktop? Please review the online installation instructions.
The Thermal Desktop menu does not appear when I open AutoCAD. This is most commonly a result of not having executed AutoCAD at least once prior to installing Thermal Desktop. You can manually register the menu using the following steps. 1) Execute AutoCAD
(or Mechanical Desktop) 2) Bring up
the Preferences dialog (Tools->Preferences for AutoCAD, Assist->Preferences
for Mechanical Desktop) 3) Click on
the "Files" tab if it is not already visible 4) Add the Thermal
Desktop installation directory path name to the "Support File
Search Path" 5) Click the
"Ok" button 6) Bring up
the Customize Menus dialog (Tools->Customize Menus for AutoCAD,
Edit->Customize Menus for Mechanical Desktop) 7) Click on
the "Browse" button 8) Set "Files
of Type:" to "Menu Template (*.mnu)" 9) Browse to
the Thermal Desktop installation directory 10) Select "thermal.mnu",
then click the "Open" button 11) Click the
"Load" button and answer "Yes" to the confirmation
dialog 12) Select the
"Menu Bar" tab 13) Select "RADCAD"
from the "Menu Group:" drop-down list box 14) Highlight
"RADCAD" in the left side list box 15) Highlight
"Help" in the right side list box 16) Click the
"Insert>>" button 17) Click the "Close" button
Error: Cannot find the file or one of its components. To open a drawing so that the alert is not displayed, adjust the Dynamic Data Exchange (DDE) settings in Folder Options:
After you ensure that the settings are correct, the file should launch the program without an error message when you double-click it.
Why use Thermal Desktop?There are many reasons to use Thermal Desktop and a full report can be found here. A quick summary of the two major reasons is listed below.
Thermal Desktop and RadCAD are integrated as a single program. RadCAD is the radiation analyzer that is embedded in Thermal Desktop. They are available separately or as a bundle.
Do I need to be proficient at AutoCAD to user Thermal Desktop? We don't expect thermal engineers to be CAD designers. Most users of Thermal Desktop will never use more than 10% of AutoCAD's capabilities, but many CAD functions are available should your needs grow. Building simple rectangles, triangles, and cylinders is as simple as pointing and clicking on the model. If you can use a mouse to point and click, then you can use Thermal Desktop to build your thermal models.
Does my organization have to use AutoCAD for me to use Thermal Desktop? AutoCAD is used as an interface to your designers CAD system via IGES, DXF, DWG, and STEP file formats. In addition you can import NASTRAN and ANSYS geometry. Once your CAD design file is imported, the Thermal Engineer can point and click to snap on familiar type rectangles, disks, cylinders, etc. to the design geometry. This capability will allow you to build your model faster than ever.
You have several options for meshing a CAD surface and turning it into a Thermal Desktop surface. In addition you can import FE meshes (see import options in the Thermal Desktop User's Manual). 1D-2D Meshing Meshing complex 2D geometry such as that shown below can be performed using the 2D mesher built into AutoCAD Mechanical Desktop. The steps to perform this type of meshing are outlined in the user's manual in section 13.1.1 AutoCAD Mechanical 2D Meshing Capability.
A third option for creating a 2D mesh is hand meshing using nodes and elements as described in section 2.11.6 of the Thermal Desktop User's Manual. Although more tedious, you may have to resort to this method if you do not have access to AutoCAD Mechanical Desktop. 3D Meshing Below are samples of an extruded Mechanical Desktop mesh (left) and EDGESURF mesh (center), and a 3D mesh of Thermal Desktop FD bricks (right). The first two options are best if you are meshing a nonorthogonal surface. For orthogonal surfaces the FD brick works well.
When using FD bricks for a 3D mesh, the placement and resolution of the bricks is important. For the FD brick example above, construction lines were created defining eight solid sections of the plate with a rectangular hole designated by the "X" as shown below. This type of layout allows you easily define identical subdivision on adjacent bricks to ensure the nodal boundaries will line up. After creating the eight FD bricks with coincident edge nodes, you will need to "Merge Coincident Nodes" to thermally connect the bricks.
A similar construction layout would be appropriate if you want to create a 3D mesh by extruding a 2D EDGERULE mesh. Use the above construction lines to created eight aligned 2D meshes in each of the sections. After merging coincident nodes, you will need to "Extrude Normal to Planer Elements into Solids".
What do the icons in the model browser represent? The icons in the model browser typically identify the type of object listed. Different objects such as a arithmetic node and a diffusion node will have different icons. These icons are useful to the user when troubleshooting or inheriting a model. Here is a complete list of the icons and what they represent.
EZ-XY Installation FAQ'sDo I need to install EZ-XY separately from other C&R products?The EZ-XY Plot Utility is downloaded with Sinda/Fluint and Thermal Desktop. Thermal Desktop automatically installs EZ-XY in the "shared" directory when Thermal Desktop is installed. For Sinda/Fluint, the EZ-XY installation is an option during installation. If you are not using Sinda/Fluint or Thermal Desktop, EZ-XY is available as a separate installaion for stand alone usage.
EZ-XY Usage FAQ'sFrom the main menu select Data Sets. A data set specifies the type of data to plot. A plot may be composed of multiple data sets.
How do I export the plot to another application? Use the export option under the FILE pull-down or, with the cursor in the plot window, press the right hand button. Then select the export dialog. This will allow the plot to be exported to a bmp, jpg or meta file. It also allows the point data to exported as text.
How can I display only a few selected curves? With the cursor
in the plot window, press the right hand button. Then select the
customization dialog. On this form select the Subsets tab. If there
are many curves and it is desired to split them into "pages,"
the user may set the scrolling subset number. This will allow the
user to set the number of curves shown on each page and to use the
scroll bar at the right of the plot to scroll through the "pages."
How can I see the data points? With the cursor in the plot window, press the right hand button. Then select the customization dialog or the Plotting Method. Then chose points or one of the "points +" display options. Once the points are displayed, when the cursor is over a point a hand will appear. When this happens, the Y value of the point will be shown in the upper left of the plot.
What if I don't have a color printer? With the cursor in the plot window, press the right hand button. Then select the Viewing Style option. Select one of the monochrome options and then print the plot.
How do I get different kinds of data onto the same plot? There are several
choices here. To combine data from multiple sources, like a text
file and Sinda/Fluint results, one would create multiple data sets.
Expressions could then be used such that the data from each source
would scale correctly, or the user might choose to place each data
set on a different Y axis.
How do I get diacriticals and symbols (like degree symbol) in axis labels? The easiest way to do this is to use the Character Map tool that was probably installed under the Accessory option of the start menu. If you don't have this tool you can use Word or some other tool that lets you type characters in various fonts. In which ever tool is used. type the desired character and then cut and paste it into the axis label field, or an annotation input field. If no tools are available, or if the correct Alt-key sequence is already know, the code for the character may be entered directly.
How can I create a plot template There are two
methods by which this can be done. The first is to set up an empty
plot so that it looks the way you want. Then save the plot. When
you want to start a new plot using its setting, double click on
this template file, or open it from within EZ-XY.
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