Check certain relations before running Parameter Correlation
In my current simulations I am modeling the flow through a nozzle, which connects a micro-channel to a fluid chamber. The model is in 2D and a pressure BC (pressure-outlet, 0 Pa static) is applied to the inlet of the micro-channel and another pressure BC (pressure-inlet, 1 kPa static) is applied to the top wall of the fluid chamber. A parametric study needs to be conducted to determine the influence of various geometric parameters. These parameters are shown in the figure below. Before conducting a DOE, I want to perform a Parameters Correlation study to find the most important parameters.
The nozzle is completely defined by 3 parameters: the nozzle throat width V11, the nozzle angle A13 and the nozzle length L12. The nozzle opening towards the chamber is reference dimension (L14) and is driven by these parameters according to (L14) = 2*(L12*tan(A13) + 1/2*V11). The fluid chamber height is also a parameter in the parametric study, indicated by H in the figure above. The vertical position of the nozzle w.r.t. the chamber is given by L33. The height of the microchannel is equal to (L14) at all times by means of a constraint.
I am able to set a lower and upper bound for the input parameters, but in order for the system to be valid, some relations must be satisfied. For example, the chamber height must at all time be larger than the nozzle opening towards the chamber, i.e H > (L14). Another example is that L33 > 1/2*(L14) such that the lowest point of the nozzle opening towards the chamber is not below the bottom of the chamber.
One option is to specify these relations as output parameters by means of an "if else" statement (1 if H > (L14) else 0 (H and (L14) replaced by their respective P#, (L14) according to expression stated above), and deleting all design points with 0), which means that I know whether the design point was valid after the simulation. However, ideally, these relations are checked before running the simulation of the design point in order to reduce the computational time of the complete parametric study.
The second option, which is my current workaround, is to
- Let Ansys generate a great amount of design points (way more design points than desired/required)
- Export the table with generated design points to a .csv file
- Open the .csv file in Matlab
- Check the relations and remove design points that fail any of the relations
- Save a as a new .csv file
- Import the new table into Ansys.
However, this method may cause certain input parameters to be unequally explored and therefore an unaccurate correlation matrix may result.
Is there a way to check these relations before starting the simulations, i.e. to not have them as output parameters?