DELX Values on WAVE

[Nishant Jain]

Hello,

I have been using Ricardo for a month now, and from what I've read and seen on results myself, the ideal way to go about designing a simple log plenum (without Wave3D which I don't have a license for) is with 4 complex Y-junctions to represent the cylinder divided into 4 equal parts, joined by massless ducts.

My question is: If for the volume of these Y-junctions I assign a certain equivalent sphere diameter (since WAVE recognizes a Y-junction as spherical) to give it the 1/4th plenum volume, how do I assign a runner tube the correct DELX value? The trouble I see is that on Wave it is a sphere whereas it is actually a cylinder. Hence, for a bellmouth runner in the actual cylinder plenum if I have a 50mm measured DELX value, DELX being the distance of the opposite wall-face from the tip of the runner, that value means something else to the spherical Y-junction on WAVE. This would be because the diameter of my cylinder is different from the equivalent diameter of my sphere on WAVE.

Should I just input the actual DELX values wrt to the log plenum, or should I use the equivalent spherical form value for that as well?

[Nishant Jain]

Hello,

I have been using Ricardo for a month now, and from what I've read and seen on results myself, the ideal way to go about designing a simple log plenum (without Wave3D which I don't have a license for) is with 4 complex Y-junctions to represent the cylinder divided into 4 equal parts, joined by massless ducts.

My question is: If for the volume of these Y-junctions I assign a certain equivalent sphere diameter (since WAVE recognizes a Y-junction as spherical) to give it the 1/4th plenum volume, how do I assign a runner tube the correct DELX value? The trouble I see is that on Wave it is a sphere whereas it is actually a cylinder. Hence, for a bellmouth runner in the actual cylinder plenum if I have a 50mm measured DELX value, DELX being the distance of the opposite wall-face from the tip of the runner, that value means something else to the spherical Y-junction on WAVE. This would be because the diameter of my cylinder is different from the equivalent diameter of my sphere on WAVE.

Should I just input the actual DELX values wrt to the log plenum, or should I use the equivalent spherical form value for that as well?

[Scrappy]

I believe that I've always used the actual distance from the runner mouth to the wall of the plenum when using the complex Y junctions. I would have to read the WAVE help files again, but I thought that they defined all the dimensions for DELX and DIAB pretty clearly with diagrams for a few different geometries.

[Nishant Jain]

I did look through the manual, but I don't think there are diagrams for different geometries. I'll look in again. Thanks, Scrappy.

[EPMAl]

I'm not 100% sure I understand your problem Actually, Wave do not necessarily consider complex Y-junction as being spheres, it can also be considered as being a cylinder. You have to set your equivalent diameter, but depending on the values you give for surface area and volume, it is going to assume it is either a sphere or cylinder (at least I think). If you try to run your plenum model through WaveMesher, I think it will calculate the proper DELX and DIAB values for your geometry.

[Nishant Jain]

So, a cylindrical plenum should be modelled by specifying the diameter of the cylinder itself, and the volume from the cylinder formula calculation? Hmmm. I'll try that.

Also, yes, I'll put it through WaveMesher.

Thanks!

[Charlie]

It's been awhile, but I believe that DELX is the expansion length variable. So it should be the distance from entry until the wall of the volume.