Modelling Filter Bypass Valve Pressure Drop 2

[KimWonGun]

I am trying to model the pressure drop across an oil filter past the cracking pressure. Attached is a chart provided by the manufacturer when the cracking pressure is 90 psi. Since I am focused on the steady state pressure drop at a given flow rate, my intent is to isolate the linear portion of the plot and create a best-fit curve and use the y-intercept as the effective cracking pressure. Is this a reasonable method?

 

[ione]

Can’t understand you. You’ve a plot reporting pressure drop vs flow provided by supplier of the item. What else do you need?

 

[KimWonGun]

By ignoring the initial ramp of the curve, I would need to assume that the cracking pressure ranges from 90 psi to the y-intercept of the linear part of the curve. In this case the difference is around 13 psi.

But when the cracking pressure is 45 psi for another filter in the same series, I am not as comfortable to just assume a cracking pressure interval of 69 psi without soliciting feedback.

 

[BigInch]

Just use y = mx + 8

Let your acquaintances be many, but your advisors one in a thousand’ ... Book of Ecclesiasticus

 

[ione]

Your filter bypass in order to operate needs a minimum constant pressure (at practically zero flow), which is indeed the cracking pressure, plus a specific pressure which varies with actual flow. If you want to neglect the steepest part of the plot (the region at very low flow) and consider just a fixed slope line, then go with the equation given by BigInch.