I am a senior design engineer at a small medical device manufacturing company. One of our products is about the size of a pen and has irrigating fluid (BSS water) flowing around an aspirating cannula with multiple diameter surfaces. Our goal is to reduce/eliminate air bubbles being formed as the irrigating fluid flows toward the tip.

Questions:

1. Can CFD software help us solve this challenge? 2. If so, are there unique requirements? 3. Is there CFD software that would do the job, be relatively inexpensive, and be easy to use (I use SolidWorks for modeling and Cosmos/Works for FEA)?

Hi Tim: Most commercial CFD codes support a hierarchy of multiphase flow models. The appropriate level for your application would require more details of the configuration since one must apriori determine whether interfacial dynamics/thermodynamics are near equilibrium. Many physical modeling issues can arise due to mass transfer, discrete interfaces, high density ratios, drag and non-drag bubble forces, low mixture sound speeds, two-phase turbulence, and others. Also, there are attendant numerical issues! Rob

Hi Tim

I think CFD could help you a lot to reduce the air bubbles in the flow. Coz the bubbles are produced where the flow pressrue is low. So you need not to simulate the multi phase flow. What you could do is to simulate the flow and find the lowest presure and plan or arrange the aspirating cannula with multiple diameter better.

Hope it help

Zhengtong