Sounds as though I am going against the grain here a bit? There are many engineering management teams that feel CFD is beyond their reach. The perception is that it is complicated, difficult to use and require a PhD to drive it. However, Structrual FEA has become almost as common as 3D CAD in many organizations. Often done "upfront" in the design process. So are structural problems so much easier to setup and solve?
In fact, there are a fair amount of decisions to be made when setting up a structural simulation of a typical mechanical assembly. Often, constraining the model can be a challenge. Also, how the parts interact can pose some questions and requires some experience to choose the correct settings. Is it bonded, sliding, frictional contact etc? What exactly is a "penalty method"?Does the model undergo large deflection, causing the analysis to be non-linear? How about material properties - elastic or plastic? FEA vendors, such as ANSYS, MSC and COSMOS have improved their interfaces substantially over the years. Some allow you to read the CAD model directly into the FEA interface. Others leverage the CAD interface and are "CAD-embedded".
So why is CFD so scary? Well, for one the equations are intrinsically non-linear. Meshing has posed some challenges, as CFD simulations tend to be more mesh sensitive than structural problems. But, the need is there. There are 100s, 1000s of companies that manufacture valves, pumps, manifolds, flow meters, fans, nozzles, medical devices, ducts, hoses etc that could substantially benefit from a flow simulation tool. Not to mention thermal effects. Think of how many mechanical designers are working in the electronics industry that would love to be able to ensure their products will not overheat once they hit the market.
If we think about the decisions that need to be made to set up a flow simulation, they are actually quite a bit less than their structural counterparts. Typically, a flow rate or pressure at the inlet and a pressure at the outlet. Material properties are just density and viscosity. Still cautious? You should be.
There are many CFD vendors that have been around for along time and have been very successful. The merger of CFX and Fluent under the ANSYS umbrella makes them the super power of CFD. Right? How about the guys at Star-CD? They speak the language of fluid guys, analysts. They are very good at what they do and serve their market very well. It just doesn't seem like they are ready to enter the design community. Can't say that I blame them. It is a complete cultural shift for them. Sure, they have "entry-level" tools but there is a huge difference between entry-level and an upfront design tool.
Entry level is exactly that. It implies a first step, the need for more at some point. Perhaps OK for some companies. But it can have a mixed message. It can be a risk for a company to make the entry level product part of their design process, but then hit the ceiling very early and then have to move on to "the real deal". They are now required to learn yet another interface, a new process, make bigger more complicated decisions. This step typically requires a significant additional investment in implementation or worse, the need to hire a specialist. Regardless of which path is chosen, the end result is the same. Less productivity, more time wasted and a lack of ROI in the end.
Instead, companies should make the assessment early on as to what their needs are for say the next three years. What kind of problems will you need to solve? What resources do you have or could you get to solve those problems? But more importantly, partner with a vendor that is focused on solving your types of problems, your way. If you are an Inventor house and design and manufacture valves, then the folks you are working with should surely be versed in both of these. They should speak your language, not require you to speak theirs.
There are vendors out there that are focused on this market- the Upfront CFD market. Certainly, don't want this to come across as a shameless plug. I am clearly a believer. But then again, I have seen all sides of the argument. Proof is in the pudding. Take a look for yourself. Jump on Google and see what all the hype is really about. I think you'll be pleasantly surprised. More to come..
No comments:
Post a Comment