Bir sol karıncık destek aygıtının tasarımı: Heart Turcica Centrifugal

Left ventricular assist devices (LVADs) are highly demanded in fighting against cardiovascular diseases which are statistically number one cause of death. In this respect, Heart Turcica Centrifugal (HTC) that is composed of a continuous centrifugal blood pump (CBP) is purposed to be developed. In development of such a device, design phase is highly challenging due to both mechanical and medical constraints such as need of small-size, high efficiency, biocompatibility. In order to satisfy the entailed design features, a regular flow within the pump is inevitable. Since the flow behavior is mainly governed by the geometry of the pump, the design tools utilized in determining the values of geometric design parameters were investigated. Design tools included One-dimensional (1-D) design procedure, Computational Fluid Dynamics (CFD) analyses, and trial and error method. In the investigation design tools, Computer Aided Design, Engineering, and Manufacturing (CAD/CAE/CAM) tools were utilized. 1-D design procedure was found to be unable to provide assistance to design since operating conditions of CBPs fall out of the valid range of the theory. CFD analyses were found to be incapable to assist the design by means of determining the values of geometric design parameters because the tool couldn?t predict the experimentally measured hydraulic performance of many designs. In contrast, trial and error method initiated with an inspiration from the findings of previous studies was quite successful in designing a CBP. An initial pump, Model 3, was manufactured with values of geometric design parameters adjusted with respect to the previous findings in literature. With respect to the experimental results of Model 3, Model 4 was manufactured with change of control parameter, impeller outer diameter, in accordance with the affinity laws. Model 4 achieved required operating conditions (5 L/min flow rate against a pressure difference of 100 mm-Hg) at a rotational speed of 3000 rpm. Further flow analyses of the pump were conducted with CFD analyses after validating the tool with successful prediction of experimentally measured hydraulic performance. Analyses of shear stress and velocity vectors pointed no risks of hemolysis or thrombogenicity. The proposed design methodology was, thus, successfully applied and yielded satisfactory results.