Shape optimization has been used for decades to improve the aerodynamic performance of automobiles and aircraft. The application of this technology to blood-wetted medical devices have been limited, in part, due to the ambiguity of hemodynamic variables associated with biocompatibility specifically hemolysis, platelet activation, and thrombus formation. This study undertook a systematic evaluation of several objective functions derived directly from the flow field. We specifically focused on the optimization of a two-dimensional blood conduit (cannula) by allowing free variation of the centerline and cross-sectional area. The flow was simulated using computational fluid dynamics (CFD) at a nominal flow rate of 6 lpm and boundary conditions consistent with an abdominally positioned left-ventricular-assist device (LVAD). The objectives were evaluated both locally and globally. The results demonstrated similarities between four of the functions: vorticity, viscous dissipation, principal shear stress, and power-law (PL) blood damage models based on shear history. Of the functions analyzed, those found to be most indicative of flow separation and clearance were flow deviation index and the Peclet Number. The conclusions from these studies will be applied to ongoing development of algorithms for optimizing the flow path of rotary blood pumps, cannula, and other blood contacting devices.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-03172006-152030 |
| Date | 02 June 2006 |
| Creators | Hund, Samuel J. |
| Contributors | James F. Antaki, Harvey S. Borovetz, Anne M. Robertson |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-03172006-152030/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.0017 seconds