Dear Experts,
What are direction cosines for a nozzle element 8" long and with direction cosines of (0.681,0, 0.733)? CII help facility doesn't really clarify signs of direction cosines. The nozzle is a discharge (side) nozzle of a vertically suspended anchored can pump.

In this case signs of direction cosines are important because the nozzle is at an angle with global(CII) axis. So nozzle loads calculated by CII in both, X and Z axes, get distributed along again in both, X and Y, axes of API-610 coordinate system. I tried a quick manual conversion from calculated loads to API 610 coordinates but I couldn't replicated API-610 module values.
I have a few other pumps similarly at weird angles. I'd much appreciate clarification on this issue.

I guess I can reword my question:

What values CAESAR II expects to be filled with in "Nozzle direction cosine X" and "Nozzle direction cosine Z" fields? Are these nozzle coordinates from the piping model point of view in CAESAR II coordinates? If so which one, suction or discharge?

Clarification is much appreciated!

Thanks!

Some examples are in Help Facility, activated by pressing [F1] after clicking on the field "Nozzle direction cosine X".

Direction cosines (or vector) in the API610 processor are used to set the shaft axis, preferably pointing away from the driver.

Thanks Dave.
It's a vertically suspended can pump so shaft axis is Y direction of CAESAR II coordinates.

I have attached the sketch of CAESAR II coordinates system with respect to API 610 coordinates system.

SO I need to only enter X vector as +0.681 and +0.733 in Z vector?

I really appreciate your input!
Thanks!

Hi Dave,
I am not sure if I understand it correctly. Am I suppose to put shaft coordinates in CAESAR II coordinates with origin at the discharge nozzle?
Thanks,

As mariog says, read the Help.

Help facility is where I started and I was not clear so I posted this question.

May be I am missing something here. The help facility says that enter nozzle direction cosines. It doesn't specify which nozzle, suction or discharge and there is only one box. In my case both are facing opposite to each other and drive shaft is perpendicular to both. It seems like that those boxes are for suction nozzle co-ordinates regardless of which nozzle is being checked. I hope this will help others too.

I think you've missed what help says for vertical in-line pump.
"Enter the direction cosines for the nozzles.
Positive direction is from discharge to suction nozzle."

I would interpret this as you must define mathematically a versor on a line between two points.

MechEngr,

You posted an attachment- figure 21 from API 610.
In that figure, the suction and discharge nozzles are as you described for your case (it would be surprising to be other way..).
I'll try to explain based on the figure's nomenclature.

I think you are required to define only pump's (API) axis "Y" in that figure.
The logic is as following: because API "Z" axis is known (is vertical) and, as vector, "Z" is down-to-up, in case you define API "Y" as a vector, API "X" vector can be calculated by the "right-hand rule". Eventually, with vectors "X", "Y" and "Z" defined, the API coordinate system will be known.

Now, as vector direction, axis "Y" is a line between points "b" and "c"; as vector sense it is a vector starting in "b" toward "c".
To define the API "Y" vector in your Caesar axes coordinates system, you must define the "direction cosines" of that vector, that's all.

Maybe Caesar help would be improved saying "Enter the direction cosines for the nozzles line".

Best regards.

Your definition makes sense and it would match the suction nozzle cosines.

I agree that CAESAR II help guidance could be clearer. If you don't know what you are suppose to put in the input, you end up on this wild goose chase to match your manual results with CII.

It could be defined as cosines of a line connecting discharge and suction nozzles with the origin at the discharge nozzle. They are really not cosines of either of the nozzles.