Linear Orifice Flow Meter Drill size Determination

Intro

The drill size is currently determined using the assumption of 5 holes in the first row of orifices and then applying that drill size to the rest of the LFOM.

Initial 5 orifices in the first row assumption.

The first row of orifies in the linear flow meter is approximating a rectangular base. Sutro altered the linear proportional weir, which has a base width that approaches infinity as the height approaches zero, by adding the rectangular base and a design restriction that the linear relationship only occurs above 1/3 the height of the rectangular base. Through trial and error a orifice number on the initial row was found to optimally be 5. The question explored here is why does the orifice value of 5 work and and does it really work for all values. The five orifices were chosen as optimal because when five orifices are used on the inital level then the subsequent rows don't encounter rounding errors, rounding errors can cause problems such as one row to contain zero orifices and the next row to contain two orifices. It is desirable to never have a subsequent row orifice number be greater then the row procedding it.

Current Research.

Currently we are looking at integrating over a height of two centimeters starting at the top of the LFOM and working our way down. this will allow us to make sure that the height is appropriate at the most critical area, the top of the LFOM where normally only 1 hole is needed. By integrating over different heights and comparing the errors associated with each option we will be able to see which row of holes is the most critical (aka causes the least amount of error).

Model optimization

I am currently working on evaluating the optimal way to determine diameter using a mathcad code. The current version of the code is available here