88 / J. Comput. Fluids Eng. Vol.20, No.2, pp.88-95, 2015. 6 1. Introduction Centrifugal blood pumps are crucial devices for cardiopulmonary bypass and circulatory assistance. Therefore, in addition to their mechanical efficiency, bio-mechanical factors have to be considered. One of these bio-mechanical factors is hemolysis, which is the release of hemoglobin from the red blood cells into the plasma. Hemolysis is also important due to the fact that high level of free hemoglobin is a toxin for the kidneys and can lead to organ failure[1]. During a blood pump operation, the main reason for the hemolysis is the shear stress generated by rotation of the rotating parts[2,3]. Due to the limitation of experiment and complexities in flow characteristics, especially inside the pump, there are obstacles for investigating the details in a real case(in vivo condition). Hence, numerical simulations are used to evaluate mechanical and bio-mechanical performances of blood pumps. Generally, there are two approaches, Eulerian and Lagrangian[4-8], to evaluate hemolysis in numerical simulations. Since the results of Lagrangian-based approaches are usually controversial and time consuming[9], an Eulerian approaches could be more appropriate. I NVESTIGATION ON M ECHANICAL AND BIO- M ECHANICAL P ERFORMANCE OF A C ENTRIFUGAL BLOOD P UMP M. Chang, 1 M. Moshfeghi, 2 N. Hur, *2,3 S. Kang, 2,3 W. Kim 2,3 and S.H. Kang 4 1 Dept. of Mechanical Engineering, Graduate School, Sogang Univ. 2 Multi-Phenomena CFD Engineering Research Center(ERC), Sogang Univ. 3 Dept. of Mechanical Engineering, Sogang Univ. 4 Dept. of Mechanical and Aerospace Engineering, Seoul National Univ. 혈액 펌프의 기계적 성능과 생체 역학적 성능에 대한 연구 장 민 욱, 1 M. Moshfeghi, 2 허 남 건, *2,3 강 성 원, 2,3 김 원 정, 2,3 강 신 형 4 1 서강대학교 대학원 기계공학과 2 서강대학교 다중현상 CFD 연구센터(ERC) 3 서강대학교 기계공학과 4 서울대학교 기계항공공학부 Blood pump analysis process includes both mechanical and bio-mechanical aspects. Since a blood pump is a mechanical device, it has to be mechanically efficient. On the other hand, blood pumps function is sensitively relate d to the blood recirculation; hence, bio-factors such as hemolysis and thrombosis become important. This p aper numerically investigates the mechanical and bio-mechanical performances of the Rotaflow in the extracorporea l membrane oxygenation(ECMO), Ventricular Assist Device(VAD), and full-load conditions. The operational conditions are defined as(400[mmHg], 5[L/min.]), (100[mmHg], 3[L/min.]), and (600[mmHg], 10[L/min.]) for ECMO, VAD, and full-load conditions, respectively. The results are presented and analyzed from the mechanical aspect via p erformance curves, and from bio-mechanical aspect via focusing on hemolytic characteristics. Regions of top and bottom cavities show recirculation in both ECMO and VAD condtions. In addition, Eulerian-based calculation of modified index o f hemolysis(MIH) has been investigated. The results demonstrate that the VAD condition has the least risk o f hemolysis among the others, while the full-load condition has the highest risk. Key Words : Centrifugal Blood Pump, CFD, Mechanical Performance, ECMO, VAD, MIH Received: May 20, 2015, Revised: June 29, 2015, Accepted: June 29, 2015. * Corresponding author, E-mail: nhur@sogang.ac.kr DOI http://dx.doi.org/10.6112/kscfe.2015.20.2.088 Ⓒ KSCFE 2015