Archive for July, 2009

The Capabilities and Limitations of Flow Simulation

Friday, July 31st, 2009

One of the grey areas of Simulation swirl around the SolidWorks Flow productline, where the capabilities and limitations are critical to ensure successful implementation. Earlier this week, we had a potential customer inquire into the functional capabilities of Flow Simulation.

Flow Simulation is an excellent mid-range fluid flow product if you are trying to simulate anything from liquids to gas flow. It can be utilized in a wide range of applications from electronics to valves to HVAC to medical and automotive/aerospace applications, and also  where fluid flow coupled with thermal analysis is a requirement.

Below is a compiled list of the capabilities and limitations of the SolidWorks Flow Simulation productline as of 2009:

What Flow Simulation can do

  • Incompressible (liquid or gas) or compressible (gas) viscous flow including subsonic, transonic and supersonic regimes
  • External and/or internal flows
  • Non-Newtonian Flows (Viscous fluids such as blood)
  • Automatic laminar/turbulent solution with transition
  • Wall roughness model
  • Swirling flows and fans (fan curves)
  • One component or up to ten independent species -liquid-liquid mixing, or gas-gas mixing
  • Forced, free or mixed convection – heat transfer
  • Conjugated heat transfer (fluid, solid), conduction and convection
  • Porous Media
  • Radiation
  • Steady state and Transient (time-dependent) fluid flow
  • Rotating Frames of Reference
  • TEC coolers/heat sink emulators/Thermostats
  • Cavitation
  • Relative Humidity

 

What Flow Simulation cannot do

  • Phase Change - The Flow package cannot handle materials cooling and transforming from gas-to-liquid, or molten liquid-to-solid. Similarly, it cannot handle materials heating from molten solid-to-liquid, or liquid-to-gas. This requires special high-end non-linear and complex formulations specifically for modeling entropy and chemical/molecular changes to account for cool down etc. Eg: plastic flow throw an injection mold as it cools and solidifies.
  • Co-existence of different phases – Flow Simulation cannot simulate a liquid and a gas in the same cavity. For instance, water flowing out of a nozzle into air (since water and air exist in the same cavity after the water flows out). Similarly, sprays (where fluid bubbles are sprayed into air). Different fluids (liquids/gases) can co-exist in a Flow Simulation if they exist in different cavities or volumes.
  • Free Surface Phenomena – Flow Simulation cannot simulate the top layer of a liquid sitting in an open tank. This again requires highly non-linear and complex formulae that are characteristic of high-end packages.
  • Moving bodies - Flow Simulation cannot simulate bodies moving and displacing fluids as they move. This requires special high-end focused packages that can handle Fluid-Structure-Interaction (FSI).
  • Combustion – Flow Simulation cannot perform chemical reactions to account for combustion.
  • Particles/Suspensions – Flow Simulation cannot simulate solid/liquid suspensions in a fluid where the suspensions can influence the pattern/parameters of flow. Since Flow Simulation cannot have two different phases in the same volume, it does not support solid particles in a fluid stream/liquid particles in a fluid stream/gas trapped in a liquid stream etc.

 

Vikram Vedantham

Simulation Product Manager 3DVision Technologies

Thermal Resistance definition for thermal contact

Friday, July 31st, 2009

In thermal analysis of assemblies, SolidWorks Simulation lets you define thermal contact resistance values. This allows you to model the thermal effect of a layer of a material which is too thin to mesh in 3D. However, the user needs to input the value of the resistance. Here is a primer on how to calculate the thermal resistance:

glue-layer2

The expected value is either the total or distributed resistance, respectively in K/W or (K.m²)/W in the SI unit system.

The basic formula for temperature drop in a thin layer of material between two parts is given by:

DT = q * [t / (k * A)]

where:

DT= temperature drop at the contact zone in K

q = heat power flowing through the contact in W

t = thickness of the layer in m

k = thermal conductivity of the layer material in W/(mK)

A = surface area of the contact in m²

 

The total thermal resistance is t/(k*A) and the distributed resistance is t/k.

heat-flow2

Thermal conductivity required to have a given thermal resistance

You can also determine the thermal conductivity required to have a given thermal resistance.

For a material of constant thickness, the total thermal resistance is Rt =  t/(k*A) and the distributed resistance is Rd = t/k.

With:

t = thickness of the layer in m

k = thermal conductivity of the layer material in W/(mK)

A = surface area of the contact in m²

Therefore, you can calculate the required thermal conductivity k to use in a material of thickness t to have the thermal resistance you need: k =  t/(Rt*A) or k = t/Rd.

Vikram Vedantham

Simulation Product Manager 3DVision Technologies

How to customize your place

Thursday, July 23rd, 2009

If you do a lot of work in Microsoft Office and find it a chore to navigate into your SolidWorks Enterprise PDM vault view, I think I have a tip you’ll love. Check out Microsoft’s knowledge base article 826214.

It shows how to add a shortcut to your vault in the My Places section of your Open and SaveAs dialogs.

myplaces

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

Columbus SWUGN Technical Summit

Wednesday, July 22nd, 2009

I was going to start this entry with “you missed a great summit”, but few of you actually did miss it. Yesterday’s technical summit had a great turnout, over 100 people were there! It was a good show. I thought the facilities were a bit small, most of the sessions had people standing in the back of the room. Even the standing people felt it was worth it.

Richard Wand at SWUGN

Richard Wand

This pic is of Richard Wand giving his weldment presentation. He continually turned his head every time I tried to take his picture. Finally I decided to just take the picture anyway.

The presentations were obviously great opportunities to learn, I picked up a few little tricks -but I enjoyed the opportunity to finally meet Dave Bartholomew – Northeast Ohio SolidWorks User Group leader during lunch. He is one of those guys who everyone knows for the good that he does for the SolidWorks community and it was nice to finally put a face with the name.

For those of you who saw Randy’s and my presentation, we were trying to decide if we should present it at SolidWorks world. Since there weren’t any survey forms, what do you think?

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

SWUGN Technical Summit – Columbus

Thursday, July 16th, 2009

You know the best way to keep up with technology is to interface with others. You also know that SolidWorks World is one of the best places to do this. Regrettably, it is sometimes hard to get an entire week off…besides who wants to go to Southern California or Florida when you live so much closer to Columbus Ohio?

All is not lost. There still is time (though not much) to sign up for Tuesday’s SWUGN Technical Summit in Columbus. Randy Simmons and I will be presenting: “In and Out of a PDM World” – showing basic strategies for file management for PDM users and non-users alike.

Just a single day, nine other breakout sessions, plus they feed you lunch too. (You knew there would be free food involved, otherwise I’d stay home.)

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

Adding without the hassle of adding a sign

Thursday, July 16th, 2009

I picked up this SolidWorks quick tip yesterday on Twitter: Double click to edit dimension, enter a number at the end of the dim, and it adds it. no “+” sign needed.

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

Still stuck in 2D? It’s time to consider an upgrade.

Wednesday, July 15th, 2009

It’s that time of year when we all think about upgrading our software to the newest versions. For all you AutoCAD guys, I’ve got a question for you. . . Don’t you wish you could get as excited about upgrades as us 3D guys get?

If you do, and I am pretty sure you do, its time to think about converting to SolidWorks.

Here is just a sampling of the advantages that SolidWorks has over AutoCAD:

1) All changes made to the 3D SolidWorks model will be updated in all locations including all drawing views.

2) SolidWorks will create an accurate BOM that will update when the assembly updates automatically.

3) You have the ability to visualize and check your model in 3D space where in AutoCAD you don’t have that luxury.

4) SolidWorks can accurately display the Mass, Volume, Surface area, Moments of intertia and Center of mass which can all be placed on the drawing with the ability to automatically update when the 3D Model changes.

Right now is a great time to convert to SolidWorks 3D. SolidWorks is offering significant savings on CAD software for qualified companies but only for a limited time. If you register by July 31, 2009, SolidWorks will analyze your business and discuss the return of investment that thousands of companies, large and small, have achieved by already moving to SolidWorks.

So what are you waiting for? Click here to register.

Josh Spencer

Elite Application Engineer, CSWE 3DVision Technologies

Don Hope gets red carpet treatment

Saturday, July 4th, 2009

People ask me if it is difficult working with Don Hope.

Hardly.

When working with Don companies always roll out the red carpet.

Don Hope and Jeff Sweeney make a visit in Sidney Ohio

Don Hope and Jeff Sweeney make a visit in Sidney Ohio

 

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

Linking to “Thickness” (trick) in SolidWorks

Wednesday, July 1st, 2009

Want the option to tie all “future” extrusions in a part to the thickness of your part ?
After you do what ever you need to do to make the first feature of your thin part (extrude & shell, revolve & shell, or just extrude, etc.)
LINK the value of the dimension that would be your “thickness” to a variable name called “Thickness”. (just double click the dimension, click on the Pull Down arrow next to dimension value, and choose Link Value, then type “Thickness”)
This will “trick” SolidWorks to turn on the “link to thickness” option in all your FUTURE Extrude, Cut, etc. commands just like when you are in a sheetmetal part !!
Then you just keep on modeling and turn ON this option as needed !!
Pretty COOL !!

Randy Simmons

Application Engineer, CSWP 3DVision Technologies

What I Learned On My Summer Vacation… (Tips & Tricks from SWworld pt.3)

Wednesday, July 1st, 2009

In a 3D Sketch create a spline perpendicular to a face.
If you just pick the SPLINE and the FACE, you get a TANGENT option. This will try to physically MOVE the spline over to TOUCH the face and be TANGENT with the face. Sometimes this is NOT what you wanted and sometimes you will end up with a NO SOLUTION FOUND problem.
More likely what you want is just for the spline to be TANGENT to the face, but not necessarily TOUCH it also…
Pick the SPLINE, the FACE, and any EDGE on the face and you will get the “hidden relation” TANGENT FACE !
You also of course get a handle that you can use to adjust the magnitude of tangency.
tangtoface1

Randy Simmons

Application Engineer, CSWP 3DVision Technologies

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