Learning Forum

[yusuf uzun]

Hi,

I am using Semi-Mechanistic Boiling(SMB) Model to model boiling in engine water jacket. As ı understood, SMB model uses Ystar value to determine the referance temperature, velocity.Also the SMB model use that reference values to calculate some fluid properties and some variables. The calculations differ when Ystar value change. 

 

So, what Ystar value should be selected?

[Ahmed Hussien]

Hi Yusuf, please check the documentation for the definition of ystar as shown in the screenshot 25.4. Setting Up the Mixture Model (ansys.com). The point here is to calculate the reference values away from the boiling wall to have a relatively homegenous temperature. Thus, a high value of 250 is assigned as default. You may conduct a sensitivity study and try different values and assess the effect on the results.

[yusuf uzun]

Is calculating the Reference variables far from wall more accurate than close to wall?