# DOE with Discreet data

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• #53072

kd
Participant

Hi All,
I’m facing problem in generating Transfer Function with one discreet & one continuous variable (2 factors). Could any one suggest me with the expertise & experience in DOE with discreet variables?
Problem-
Factors
a, Diameter of Holes
b, Number of holes
2K full factorial runs with above parameters. My main objective is to reduce the number of holes but do not want to sacrifice the performance. The holes were located circumferentially and equally spaced.
Question-
Whether developed Transfer function with above factors (equally spaced) will be validate for hole located circumferentially and not equally spaced?
Thanks for helping
KD

0
#187792

Remi
Participant

Hai KD,
the correct answer is: it depends.
If y = air usage, it does not matter how the holes are placed. The air usage is the Area of all the holes together.
If Y = cooling strength on a small area, then situation with holes all near the centre gives a different result than holes on the border.
So the question is: what is your Y=CTQ and how is it influenced by the X’s. The function itself is just a mathematical model for this relation.
Remi

0
#187793

kd
Participant

Hi Remi,
Thanks for you reply, my CTQ is flow in the holes. In my case I cannot bring the holes near to center so I fixed one diameter.
Thanks
Deevakar

0
#187808

Robert Butler
Participant

It sounds like you actually have three variables
1. Hole Diameter
3. Location of hole(s) along radius
According to your initial post you have fixed #3 at an arbitrary value and therefore are assuming hole location relative to center doesn’t matter.  I understand the reasoning behind the choice but in addition to assuming location from center doesn’t matter you are also assuming a pattern of various holes at different radii from the center is equal to a pattern of holes at a fixed radius. I don’t understand how this could be the case.
As for #2 – if you use radial location then you could model the effects of symmetric and non-symmetric hole distribution (for example 4 holes evenly spaced 90 degrees apart vs. 4 holes 30 degrees either side of the 0-180 axis)
Even with only. #1 and #2 there are a huge number of possible combinations.  If you have some kind of prior knowledge about hole sizes and hole patterns and their performance you might be able to use this infomation to guide you with respect to identifying combinations that would reduce the choices for experimental combinations to something more manageable.

0
#187909

kd
Participant

Hello Robert,