The Bubble number density result shows the density of bubbles through the part as the analysis progresses.
This result is generated from a Microcellular injection molding analysis, for the following mesh types:
Midplane 
Dual Domain 
3D
Using this result
If you selected the Constant Nucleation model, the bubble number density result will be uniform throughout the part and will reflect the value you entered in the Process Settings dialog, under Number of cells per volume.
If you selected the Fitted Classical Bubble Nucleation model, this model predicts the number of bubbles in any area of the part at the end of the analysis, and depends on the nature and volume of the foaming gas, the polymer properties, the local temperature, and the pressure.
Ideally, the bubble number density should be fairly uniform throughout the core regions of the part. An area with very few bubbles may indicate that there is insufficient foaming (SFC) gas present, or that the part froze early before the pressure decreased sufficiently to allow bubble growth.
To specify the numbers of profiled results to output , click 
(), if necessary click Next to access the Fill+Pack Settings page. Click Advanced options, click Edit in the Solver parameters group, then, select the Intermediate Output tab and ensure the number of profiled results is greater than zero.
Things to look for
You may want to study the bubble size result in conjunction with this result.
- Cells only in low pressure areas indicate insufficient foaming agent. Consider increasing the concentration of the foaming agent.
- Cells only at the end of fill indicate insufficient foaming agent. Consider increasing the concentration of the foaming agent.