Learning Forum

[Jpret99]

HI all, I've modelled a gas turbine blade in static structural which has a rotational velocity of 3000 rpm, and a surface pressure and body temperature which has been imported from CFX results. I’m running different models which have different thermal coating thicknesses. Increasing the thicknesses resulted in lower overall temperatures on the blades surface. In theory, the stress correlating to the lower temperature of the blade should be lower due to lower thermal strains. However, I have a consistent trend where the stress increases with a decrease in body temperature. This makes no sense to me, and I can’t think of any reasoning behind this behaviour. Everything is constant between each model, besides the body temperature, so there shouldn’t be any conflict due to inconsistent parameters etc. The material used for the blade is IN-625 from Ansys engineering data, so all the relevant properties should be correct.

The temperature contour and stress for a 0.5mm coating thickness is shown below.

[Ashish Khemka]

How is the mesh at the bottom region of stress concentration (near fillet)? Is it converged? There is not a significant change in temperature between the two temperature loads and hence almost similar levels of stress.

Regards Ashish Khemka

[Jpret99]

i have not run a specific convergence as the model becomes too large to solve for my PC and i cant simplify it down any further. I am already using quite fine mesh however. I know that the temperature differences aren't significant, but the trend occurs for all 10 models of varied thermal coating thickness, where further temperature reduction results in larger stresses. So i believe the case isn't a once off due to an error in the solving process