Thursday, July 10, 2008

When Everyday Life & CFD Converge

My wife convinced me to put a pool in our backyard. Probably not what you are thinking. You immediately thought in-ground, diving board with a slide and grotto, right? Not even close. We purchased an Easy Set Pool. You know the kind with the blow up ring at the top and you just fill it with water. Well, 3 pool fills later on uneven ground, the pool is up and running. "Easy" is all relative.

It comes with its own pumping filtration system. Enter the CFD part of the story. I turned it on initially and was amazed how quiet it was and the pumping power was amazing. Over the course of a couple weeks, I noticed that the pump was not cleaning the pool. I then noticed that there were large pockets of air at the discharge of the pump. I vented the pump numerous times and it seemed to be ok, but eventually would lose suction. Really cool to see cavitation in action and the effect it has on the performance of the pump.

Not one to read directions, I figured it was time. Sure enough, it recommended changing the filter on the pump every few weeks. I quickly changed out the filter and was having a great time checking out the internals of the pump, impeller, filter etc.. The filter was packed with all kinds of stuff, clearly impeding the performance of the pump. I have seen literally 100s of pump CAD models and run countless CFD analyses on pumps but haven't seen the inside of too many in person. I quickly re-assembled and the pump worked like a charm. It made me appreciate even more the challenges that manufactures have to go through everyday to ensure their products perform as expected. Competition is tough everywhere and you have to get it right the first time.

Above is a model we did for Davey Water Pumps awhile back. Click on the image for more details as well. They were able to improve efficiency by 15% by redesigning the pump in CAD and leveraging the CFD results to drive the design changes. As consumers, we just expect that the pump will work all the time. Pump manufactures surely have a difficult challenge to package the pump in a small area, make it as efficient as possible, quiet as possible and sell for less than $100. There has to be a streamlined way for designers to gain insight to their designs.

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