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Topics related to Fluent, CFX, Turbogrid and more.

Thermal Analysis of Sealed Cabinet

    • menastap
      Subscriber

      Hi , hope all you are doing well. I have to find the temperature inside the cabinet while elextronics installed dissipate 1750 watt heat. As per my understanding, i can do this through steady thermal analysis . I have tried but solution can't run beacuse of memory issues. Please guide me , how do i make it possible with limited memory source. Below figure depicts the defined geometry

    • Rob
      Forum Moderator

      You'll be better off asking in the Mechanical channel. For CFD I'd make a few assumptions regarding the casing and then model the buoyant flow. 

    • Pedram Samadian
      Ansys Employee

      Hi,

      Thanks for contacting us. When you encounter memory issues in LS-DYNA, especially with limited memory resources, there are several ways to optimize your simulation for more efficient memory use, which are outlined below:

      – Reduce the Element Count

      • Mesh Optimization: Use a coarser mesh in regions where high accuracy is not crucial and apply a finer mesh only in areas of interest (e.g., stress concentration zones). This reduces the memory needed to store and compute element data.

      – Use a Single Precision Version of LS-DYNA

      • Single Precision Solver: Run the solver in single precision if double precision isn’t required for your application. Single precision uses half the memory of double precision and can still yield good results, especially for non-high-accuracy simulations.

      – Optimize Contact Definitions

      • Simplify Contact Types: Use simpler contact definitions where possible. For instance, *CONTACT_AUTOMATIC_SINGLE_SURFACE consumes more memory than *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE. Only use the former if absolutely necessary.

      – Reduce Output Frequency

      • Database Output: Lower the output frequency of results files like D3PLOT and GLSTAT, which consume a lot of memory and disk space. For example, change from every 0.1 ms to every 1 ms if appropriate.
      • Selective Output: Disable unnecessary outputs, or only save variables critical to the analysis. For example, avoid saving stress and strain at every time step if they are not essential.

      – Run on Fewer Processors

      • Processor Adjustment: Running on too many processors with limited memory can lead to memory fragmentation and increased demands. Try reducing the number of processors to optimize memory use, especially on machines with limited cores and RAM.

      – Simplify Element Types

      • Switch to Simpler Elements: If your model allows, use simpler elements (e.g., reduce higher-order elements to linear elements) to cut down on memory use.

      If you continue to experience difficulties, it may be beneficial to consult the LS-DYNA user documentation or reach out to Ansys support for more targeted advice on managing memory usage for your specific simulation scenario.

      Thanks,

      Pedram

       

       

    • Deepak
      Ansys Employee
      Hi, Can you please check with the difficult mesh setting? Thanks, Deepak
    • menastap
      Subscriber

      Thanks alot to all. I  will try, hopefully issue will be resolved

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