I am doing hp stage analysis for a steam turbine,when i am using material as 'water ideal gas' I am getting results which are varying around 10% with practical data, but when i am using dry steam in cfx 10.0 as a material I am getting something nonsense, please any body worked in this field help me.

Are you using the RGP table for dry steam? If so, is there any clipping reported in your out file?

I am using drysteam and rgp table, I am using cfx 10 when I am referring rgp table I am getting a error in blue color saying that "the material selected does not have thermal conductivity or specific heat".

The error message given by the GUI is a bug. It is fixed in CFX 11.0. Don't worry about it.

Johnny is correct. In CFX 10.0 the presupplied RGP files for steam only allow for certain ranges of temperature and pressure. See the material description in the lower message bar in CFX Pre. When you select a material it must correspond to the pressure and temperature range of your device.

If one of the pre-supplied RGP files does not have a correct range then you will have to use the Redlich Kwong equation of state materials instead. With these materials you can customize the pressure and temperature ranges which the tables are built for inside the solver.