很好的

airpak常见问题问与答（一）建模基础

1) My model is very complicated, what is the best way to build it ? ....................................... 3

2) How can I simplify my model? ............................................................................................... 3

3) How often shall I save? ........................................................................................................... 3

4) I am making models with only small changes between them, shall I save them under

different names or get different solutions under the same name? .............................................. 3

5) My area of interest is not surrounded by walls on all sides, is it OK to use the room

walls or should I put openings on these walls? ............................................................................. 4

6) Should I include the effect of gravity in my model? ............................................................. 4

7) Should I include the effect of radiation in my model? ......................................................... 4

8) The calculation for the view-factor matrix is taking too long, what is happening? .......... 5

9) How do I decide whether the flow is turbulent or laminar? ................................................ 5

10) Is is easier to import a model from a CAD package or construct the model inside

Airpak? ............................................................................................................................................ 5

11) What are the CAD package files I can import into Airpak? ........................................... 5

12) What units should I use? .................................................................................................... 6

13) How do I take the effect of elevation into account?.......................................................... 6

14) My model is symmetric but my solution is not, what is the reason? ............................... 6

15) What is a typical magnitude of flow velocity due to (pure) natural convection? .......... 6

16) Can I predict condensation in a room? ............................................................................. 6

17) My Airpak jobs are taking up too much disk space, what should I do?......................... 7

18) How can I free-up disk space without deleting model, mesh and postprocessing files? 7

19) What are the three most essential files of an Airpak model? .......................................... 7

20) What does "pack" and "unpack" mean? ......................................................................... 7

21) How do I print out an Airpak model? ............................................................................... 7

22) Where do I define my units? .............................................................................................. 8

23) How do I run a time-dependent or unsteady simulation? ............................................... 8

24) What are initial conditions? ............................................................................................... 8

25) What is the "Minimum object separation"? .................................................................... 8

26) What is the meaning of "Radiation temperature" on the "Problem/Setup" menu? .... 9

27) My Airpak model is so cluttered, what should I do to see the model more clearly? ..... 9

28) How can I suppress the view of objects in Airpak? .......................................................... 9

29) Sometimes the dimensions of objects contain too many decimal places: Is there a way

to avoid this situation? .................................................................................................................... 9

30) How do I move, copy or scale a group of objects at the same time? ............................... 9

31) How do I move a group of objects using the mouse? ..................................................... 10

32) How can I change the specifications (material type, power, etc.) of a group of objects

in my model? ................................................................................................................................. 10

33) What is a part? .................................................................................................................. 10

34) How can I scale an object with different scale factors in each of the coordinate

directions? ...................................................................................................................................... 10

35) How do I reverse the order of object creation? .............................................................. 10

36) How do I change the default values of material properties? ......................................... 11