Cadalyst - March 2008 - (Page 14)

techtrends To simulate and study how blood would flow into the flow cell, Luminous’ engineering team used the COSMOSFloWorks CFD program for SolidWorks. The program features non-Newtonian fluid flow, precisely what Novkov needed to study blood flow in the device. COSMOSFloWorks is intended for the valve/regulator, medical, electronics, and oil and gas industries, among others. The software analyzes conjugate heat transfer; subsonic, supersonic, and compressible flows; mixing of gases; flow around rotating geometry; porous media; cavitation; humidity and climate control; fluid structure interaction; and more. With the release of COSMOSFloWorks 2008, the company expanded its engineering database for both Newtonian and non-Newtonian liquids. The non-Newtonian additions include applesauce, blood, olive oil, polyethylene, polystyrene, and slurries (figure 3). “Non-Newtonian flow is so complicated that you’re bound to need software to figure it out,” Novkov remarked. “It’s one of the reasons we bought the software. In fact, I’m sure we would not have bought [COSMOSFloWorks] if [non-Newtonian flow] weren’t in the feature list.” At one point, the engineers noticed something odd about the blood flow inside the device, as revealed by COSMOSFloWorks. “It was a flow that had a nonuniform profile,” recalled Novkov. “That would make it difficult for the flow cell to wash out the saline fluid [pumped in behind the blood], which in turn would make the spectroscopic reading less accurate.” Novkov’s engineering instinct told him he would have to modify the geometry of the flow path leading to the cell to get a better distribution model. It took him three or four iterations to get the correct velocity and circulation. Figure 2. Luminous Medical’s glucose-measuring system was designed in SolidWorks, making it ideal for downstream analysis in COSMOSFloWorks, a computational fluid dynamics analysis program for SolidWorks users. Temperature Watch After the device has measured the glucose content of the blood, the blood within the flow cell is pumped back into the patient. Therefore, it is critical to ensure the infrared light doesn’t raise the temperature of the blood. “We performed tests of the device instrumented with thermistors and measured no significant temperature increase, so we were fairly certain the process wouldn’t heat up the blood,” Novkov said. “But we didn’t want to take chances. We wanted to validate it. We didn’t buy COSMOSFloWorks for that purpose. Since we had the software, we decided we should run the analysis and generate a report.” Through the use of COSMOSFloWorks, Novkov and his colleagues were able to perform a heat-transfer analysis to ascertain that no significant heat would be imparted to the blood through the device’s operation. The software, observed Novkov, “is fairly user friendly. The interface with SolidWorks was seamless. You don’t have to pay a lot of attention to generating meshes. Figure 3. COSMOSFloWorks lets users simulate and model the flow patterns of non-Newtonian fluid such as blood, toothpaste, or paint. The image here shows the simulated flow of molten plastic through an extrusion channel under high pressure. I put the software to use with only a few tweaks to the default parameters.” A fluid dynamics veteran, Novkov can recall the times when he had to manually calculate the operations now automatically performed by COSMOSFloWorks. Leaving the complex calculation tasks to the software is “a pleasure,” he said. The Luminous Medical Glucose Measurement System, as the product is now known, is in preproduction, pending U.S. Food and Drug Administration review. c Cadalyst contributing editor Kenneth Wong explores innovative uses of technology and its implications in his writing. Reach him at kenneth.wong at cadalyst.com. 14 March 2008 | cadalyst | www.cadalyst.com http://www.cadalyst.com

Table of Contents Feed for the Digital Edition of Cadalyst - March 2008

Cadalyst - March 2008 Contents Editor's Window CAD Central Thicker than Water Safe Keeping — Backup Software Secures Your Designs AMD’s ATI FireGL Graphics Cards AutoCAD Civil 3D 2008 — Surveying, Civil Engineering, and Land Development Software Cool Software Utilities for Your Job History, Nonhistory, or Both? In the Eye of the Storm Builders’ Information Modeling CAD Cartoon Issue Indexes CAD from the Streets

Cadalyst - March 2008

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