Non destructive examination of the inside of a nozzle

[Nick87]

Hi

I have a nozzle that has a converging section, a diverging section, followed by another converging section at the nozzle tip. The nozzle is about 0.5'' inside diameter at the converging sections. The nozzle is about 3.5' long and has a constant outside diameter of 1''. It is made of steel, although I am not sure what type (classified). The nozzle tip has eroded significantly. I need to determine how the geometry of the inside of this nozzle has changed. I would really prefer not to cut it open, as it is needed for tests to determine how the erosion has impacted the spray quality. As well, I would use a mold, but it may not give me all the details of the internal geometry that I need, and it is hard to pull out of the nozzle and keep intact once it has set.

Are there any non-destructive examination tests that I could use to determine what the nozzle looks like on the inside so that I can get a good visual of where the erosion inside the nozzle has occurred? Thanks!

Regards,

Nick

 

[btrueblood]

Flexible borescope and video camera?

 

[micalbrch]

You can try to x-ray it but you need the device and the experience to judge the pictures. If you do not have both, it will most probably be cheaper to cut the nozzle.

 

[metengr]

If you cannot access the nozzle ID surface using a remote fiber optic borescope, I would consider either digital RT combined with UT thickness testing or remote field eddy current testing.

I have found digital RT provides excellent sensitivity to density changes related to material loss. The remote field eddy current testing can be done from the outside surface of the nozzle.

 

[1gibson]

Could you cast some silicone rubber inside the nozzle, then remove it? You would have some details to figure out so that you can remove the plug of silicone, but it should be feasible with the right stuff, Smooth-on makes a lot of two part silicone casting rubbers with varying durometers.

 

[mrfailure]

Have you considered IRIS inspection?

 

[Nick87]

Thanks for the suggestions. Does IRIS work with tubes of varying cross sectional area? The cross sectional area of this nozzle varies between 0.5'' and about 0.88''.

I have considered a mold. I am going to try that, but I need the mold to fit through the tip of the nozzle, which is 0.5''. The widest part of the nozzle is about 0.88''. Therefore I am not sure that the mold will stay intact as I try to pull it out, and I am afraid the details of the erosion will be lost.

Thanks for the replies.

 

[mrfailure]

1/2" size should be no problem with IRIS. The question is whether this can be kept flooded with water to make the measurements given that it is a nozzle.