Gap Study

[goodguy1405]

My boss came to me this morning and asked me to do a gap study on our new design concept. I have never done one and do not know where to look to even begin. Also he wants me to conduct a flow analysis across the cross sectional area of the gap. Help... Thanks in advance.

 

[chicopee]

I am just in the "blind" as you are because you have not described the problem that involves whatever system. Describe in fuller details what you are working on.

 

[goodguy1405]

Now we are both blind. He just came back in to explain further. He wanted to me to calculate the percentage of flow through 2 different cross sectional areas. Just wanting to know what percentage of fluid is being diverted from the main flow hole. At my last job they showed me one time how to do a gap study in the design process but I have yet to understand where they get the criteria to even begin a study. Is there another name for a gap study I am not familiar with?

 

[chicopee]

So, we seem to be looking at a hydraulic problem that involves what? pipe drainage, hydraulic fluid piping, pneumatic system....?

 

[goodguy1405]

This deals with mud flow through flow holes. Wanting to calculate the drop in pressure due to the 2 different flow holes. One being a direct flow hole and the other being the cross sectional area between 2 parts.

 

[Tmoose]

I'd say it is a bit more complicated than comparing the ratio of the areas, which is almost always the "first cut" that Folks use. (In some groups in some companies in some industries it seems Sometimes it's the final cut, too).
As you describe the system as having "gaps" I guess the resistance, etc factors produced for sudden expansions and contractions by common pipe flow calculators won't be much help.

 

[goodguy1405]

The boss was needing this calculation to let the drilling rig know a percentage of fluid loss across the gap versus the flow hole. I am an entry level engineer trying to make it....I have a lot left to learn and on to the bachelor's degree next semester.

 

[SnTMan]

Got your fluid mechanics textbook handy?

Regards,

Mike

 

[goodguy1405]

I have it. Understanding it is completely different.

 

[SnTMan]

Ask a co-worker for a "go-by" calculation?

 

[tbuelna]

The first step would be to establish the orifice flow coefficients for your two cases. You need to consider factors like length/flow area of the restriction, geometry of the inlet/outlet, relative pressures and flow velocities across the restriction, etc.

You will also need the properties for the fluid being considered. I can imagine that your drilling mud might have some unusual fluid characteristics. Particulate solids suspended in a fluid.

 

[rb1957]

can you get hold of a previous anlaysis your company did ?

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