for thermal analysis i am using fem software ANSYS. and in that i have found warning that you have crossed the limit of the aspect ratio. and then i have changed the limit of the aspect ratio. so i have a question that does any change in aspect ratio make any change in my analysis?

so pl reply me thanks

Yes, bad aspect ratios can interfere in your result and it was already subject of research for incompressible flows in finite element analysis

For further details, take a look in:

S. Mittal, "On the performance of high aspect ratio elements for incompressible flows ", Comput. Methods Appl. Mech. Engrg. 188 (2000) 269-287.

Cheers

Renato.

I've forgot to mention something...

If your model is too much complex and your have few elements with bad aspect ratio "lost" in regions with small gradients I think you don't need to bother about them. These bad elements probably will only disturb your solution convergence.

I've already done the same thing you've cited in your post with Ansys/Flotran but I was not able to see any big diference in my result (I had less than 1% of bad elements in a huge mesh)

Cheers

Renato.