A multi-phase CFD method is used to analyze centrifugal pump performance under developed cavitati... more A multi-phase CFD method is used to analyze centrifugal pump performance under developed cavitating conditions. The differential model employed is the homogeneous two-phase Reynolds-Averaged-Navier-Stokes equations, wherein mixture momentum and volume continuity equations are solved along with vapor volume fraction continuity. Mass transfer modeling is provided for the phase change associated with sheet cavitation. Quasi-three-dimensional (Q3D) and fully-three-dimensional analyses are performed for two impeller configurations. Using Q3D analysis, steady and time-dependent analyses were performed across a wide range of flow coefficients and cavitation numbers. Characteristic performance trends associated with offdesign flow and blade cavitation are observed. The rapid drop in head coefficient at low cavitation numbers (breakdown) is captured for all flow coefficients. Local flow field solution plots elucidate the principal physical mechanisms associated with the onset of breakdown. Results are also presented which illustrate the full three dimensional capability of the method.
Minimally invasive open heart surgery involves limited intrathoracic cannulation sites necessitat... more Minimally invasive open heart surgery involves limited intrathoracic cannulation sites necessitating cardiopulmonary bypass to be initiated via peripheral access using percutaneous cannulae with the tip placed into the right atrial cavity. However, surgery involving the opening of the right heart obliges the surgeon to maintain the end of the cannulae into the vena cavae. The impeded venous return due to the smaller diameter may be alleviated by inserting a centrifugal pump in the venous line. Methods: Right anterior mini-thoracotomy and exposure of the femoral site were performed before the patient was heparinized. Cannulation of the femoral artery, the inferior vena cava via the femoral vein and the superior vena cava through the mini-thoracotomy was performed and cardiopulmonary bypass was initiated. Venous drainage was augmented with the centrifugal pump. Cardiac arrest was provoked and both vena cavae were snared before performing the intracardiac procedure. Results: Twenty consecutive patients were operated on using this technique (15 males/®ve females; age: 44:8^14:3 years; bodyweight: 73:5^15:1 kg; body surface area: 1:8^0:2 m 2 ; theoretical blood¯ow rate: 4:4^0:5 l/min). The cannula sizes were 21:9^2:2 Fr for the femoral artery, 26:5^1:7 Fr for the inferior vena cava and 23:8^2:5 Fr for the superior vena cava. Venous drainage through the single inferior vena cava cannula was 2:1^0:6 l/min (48:8^13:3% of the theoretical¯ow). Adding the superior vena cava cannula increased the venous¯ow to 3:1^0:4 l/min (70:7^9:6% of the theoretical value, P , 0:005). The use of the centrifugal pump increased the¯ow to 4:1^0:6 l/min (93:4^8:9% of the theoretical¯ow, P , 0:001) with a mean inlet negative pressure of 269:1^10:2 mmHg. The mean bypass time was 64:0^24:6 min for a mean operative time of 226:3^61:0 min. Minimum venous saturation was 69:4^8:5%. Conclusions: Despite the smaller diameter of the vena cavae compared to the right atrium, and a smaller internal diameter of percutaneous cardiopulmonary bypass cannulae compared to classic ones; the centrifugal pump improves the venous drainage signi®cantly so that minimally invasive open heart procedures can be performed under optimal and safe perfusion conditions. q 1999 Elsevier Science B.V. All rights reserved.
... velocity calculation / 166 Detailed three-dimensional blade design / 167 Two-dimensional blad... more ... velocity calculation / 166 Detailed three-dimensional blade design / 167 Two-dimensional bladedesign / 173 Return ... Kaupert, KA, Holbein, P., Staubli, T. (1996): A First Analysis of Flow Field Hysteresis ... The effects of viscosity are neglected and the flow is assumed to be inviscid. ...
A multi-phase CFD method is used to analyze centrifugal pump performance under developed cavitati... more A multi-phase CFD method is used to analyze centrifugal pump performance under developed cavitating conditions. The differential model employed is the homogeneous two-phase Reynolds-Averaged-Navier-Stokes equations, wherein mixture momentum and volume continuity equations are solved along with vapor volume fraction continuity. Mass transfer modeling is provided for the phase change associated with sheet cavitation. Quasi-three-dimensional (Q3D) and fully-three-dimensional analyses are performed for two impeller configurations. Using Q3D analysis, steady and time-dependent analyses were performed across a wide range of flow coefficients and cavitation numbers. Characteristic performance trends associated with offdesign flow and blade cavitation are observed. The rapid drop in head coefficient at low cavitation numbers (breakdown) is captured for all flow coefficients. Local flow field solution plots elucidate the principal physical mechanisms associated with the onset of breakdown. Results are also presented which illustrate the full three dimensional capability of the method.
Minimally invasive open heart surgery involves limited intrathoracic cannulation sites necessitat... more Minimally invasive open heart surgery involves limited intrathoracic cannulation sites necessitating cardiopulmonary bypass to be initiated via peripheral access using percutaneous cannulae with the tip placed into the right atrial cavity. However, surgery involving the opening of the right heart obliges the surgeon to maintain the end of the cannulae into the vena cavae. The impeded venous return due to the smaller diameter may be alleviated by inserting a centrifugal pump in the venous line. Methods: Right anterior mini-thoracotomy and exposure of the femoral site were performed before the patient was heparinized. Cannulation of the femoral artery, the inferior vena cava via the femoral vein and the superior vena cava through the mini-thoracotomy was performed and cardiopulmonary bypass was initiated. Venous drainage was augmented with the centrifugal pump. Cardiac arrest was provoked and both vena cavae were snared before performing the intracardiac procedure. Results: Twenty consecutive patients were operated on using this technique (15 males/®ve females; age: 44:8^14:3 years; bodyweight: 73:5^15:1 kg; body surface area: 1:8^0:2 m 2 ; theoretical blood¯ow rate: 4:4^0:5 l/min). The cannula sizes were 21:9^2:2 Fr for the femoral artery, 26:5^1:7 Fr for the inferior vena cava and 23:8^2:5 Fr for the superior vena cava. Venous drainage through the single inferior vena cava cannula was 2:1^0:6 l/min (48:8^13:3% of the theoretical¯ow). Adding the superior vena cava cannula increased the venous¯ow to 3:1^0:4 l/min (70:7^9:6% of the theoretical value, P , 0:005). The use of the centrifugal pump increased the¯ow to 4:1^0:6 l/min (93:4^8:9% of the theoretical¯ow, P , 0:001) with a mean inlet negative pressure of 269:1^10:2 mmHg. The mean bypass time was 64:0^24:6 min for a mean operative time of 226:3^61:0 min. Minimum venous saturation was 69:4^8:5%. Conclusions: Despite the smaller diameter of the vena cavae compared to the right atrium, and a smaller internal diameter of percutaneous cardiopulmonary bypass cannulae compared to classic ones; the centrifugal pump improves the venous drainage signi®cantly so that minimally invasive open heart procedures can be performed under optimal and safe perfusion conditions. q 1999 Elsevier Science B.V. All rights reserved.
... velocity calculation / 166 Detailed three-dimensional blade design / 167 Two-dimensional blad... more ... velocity calculation / 166 Detailed three-dimensional blade design / 167 Two-dimensional bladedesign / 173 Return ... Kaupert, KA, Holbein, P., Staubli, T. (1996): A First Analysis of Flow Field Hysteresis ... The effects of viscosity are neglected and the flow is assumed to be inviscid. ...
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