Effects of Tongue Position and Base Circle Diameter on the Performance of a Centrifugal Blood Pump

Wong, Y. W.; Chan, W.K.; Wei, Hu

doi:10.1111/j.1525-1594.2007.00430.x

Cited by 15 publications

(10 citation statements)

References 22 publications

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“…The constant angular momentum (CAM) method was used for the H6DL series with a constant ow angle of 3.55 according to a previous report [10]. The position of 15 was determined following a recommendation from Wong et al [11] The radial clearance was widened by changing the diameter of the volute base circle. Structured hexagonal meshes for the inlet and outlet domains were created using ANSYS Meshing (ANSYS, Inc., Canonsburg, PA, USA).…”

Section: Numerical Analysis Settingmentioning

confidence: 99%

“…For the pump design, the radial passive stability can be improved with an optimal volute design by reducing the radial hydraulic force on the impeller [10][11][12][13]. Under the wide range of ow rate conditions that vary with the beating heart, a double volute would be adequate to cancel the radial hydraulic force generated by an unbalanced pressure eld around an impeller at an off-design point [12,14].…”

Section: Introductionmentioning

confidence: 99%

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Effects of Eccentric Impeller Position on Radial Passive Stability in a Magnetically Levitated Centrifugal Blood Pump with a Double Volute

Shida

Masuzawa

Osa

et al. 2018

ABE

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Evaluation of the impeller radial stability is important from the bioengineering point of view in the development of mechanical circulatory support devices (MCSDs) for safer use as bridge for several months or destination therapy for years. In this study, radial stability of a magnetically levitated impeller in a centrifugal blood pump with an axially magnetic suspension system was evaluated by investigating the effects of the eccentric impeller position on passive stability, aiming to propose a pump design guide for the development and safer clinical use of MCSDs. First, impeller displacements in the prototype pump were measured using a mock loop together with laser displacement sensors. Then, the radial hydraulic forces exerted on an eccentric impeller were calculated using computational uid dynamics (CFD) analysis for four volute-casing geometries. In addition, hemocompatibility was assessed using CFD calculations of scalar shear stress exerted on blood. Measurement of impeller displacement showed that the displacement varied from 0.56 to 0.27 mm at a rotational speed of 1800 rpm as the ow rate increased from 0 to 6.5 L/min. In the CFD calculation, the radial hydraulic force increased linearly from 0.2 to 1.7 N as the impeller displacement increased from 0 to 0.5 mm for all the double volute geometries, under conditions of a rotational speed of 1800 rpm and ow rates of 3, 5 and 7 L/ min. These results indicate that the impeller stability in the prototype pump is acceptable at the operation conditions of ventricular assist devices, because the magnetic bearing stiffness of radial component was 4.1 N/mm. In the pressure recovery analysis of eccentric impellers, a double volute was not effective because of the unbalanced pressure eld generated by the unbalanced pressure recovery. Thus, the increase in radial hydraulic force associated with an eccentric impeller could not be avoided by changing the conventional double volute design. The CFD analysis of geometrical variation indicated that widening of the radial clearance is an effective approach to improve the radial stability as well as hemocompatibility, although the radial clearance should be designed based on trade-offs among impeller stability, hemocompatibility and pump performance.

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Section: Numerical Analysis Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Eccentric Impeller Position on Radial Passive Stability in a Magnetically Levitated Centrifugal Blood Pump with a Double Volute

Shida

Masuzawa

Osa

et al. 2018

ABE

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“…This corresponds to a different character (mode) of flow in whole spiral case which is due to smaller outer area of blade channels. Another major factor in terms of losses will be different influence of the impeller around the spiral case nose [7]. From the figure 9 it is evident, that the gap between the hub and pump stator parts has stabilizing effect in impellers with thick trailing edges.…”

Section: Energy Dissipation Within the Pumpmentioning

confidence: 99%

Hydraulic losses in the spiral case of low specific speed pumps

Klas

Pochylý

Rudolf

2014

EPJ Web of Conferences

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Abstract. This contribution is focused on analysis of pressure losses in spiral case of centrifugal pump with thick trailing edges and with recirculation channels. Recirculation channels have different geometrical configuration and influence the size of available specific energy as well as hydraulic efficiency. Subsequently, the contribution analyses the flow in spiral case itself with respect to its function and its filling with liquid. Studied phenomena affect the research of pumps with low specific speed, the stability of specific energy characteristic curves and also the configuration of recirculation channels.

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“…Nevertheless, similar characteristics are present as in regular centrifugal pumps (7–11). Depending on the impeller and volute design, impeller‐to‐volute positioning and pump‐operating conditions, the acting forces, both the magnitude and the direction, on the impeller can vary, which has partly been investigated for centrifugal blood pumps (7,8,12–17). In the development of third‐generation centrifugal blood pumps, knowledge of the forces acting on the impeller is crucial for the design of the impeller suspension system.…”

mentioning

confidence: 99%

Evaluation of Hydraulic Radial Forces on the Impeller by the Volute in a Centrifugal Rotary Blood Pump

et al. 2011

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In many state-of-the-art rotary blood pumps for long-term ventricular assistance, the impeller is suspended within the casing by magnetic or hydrodynamic means. For the design of such suspension systems, profound knowledge of the acting forces on the impeller is crucial. Hydrodynamic bearings running at low clearance gaps can yield increased blood damage and magnetic bearings counteracting high forces consume excessive power. Most current rotary blood pump devices with contactless bearings are centrifugal pumps that incorporate a radial diffuser volute where hydraulic forces on the impeller develop. The yielding radial forces are highly dependent on impeller design, operating point and volute design. There are three basic types of volute design--singular, circular, and double volute. In this study, the hydraulic radial forces on the impeller created by the volute in an investigational centrifugal blood pump are evaluated and discussed with regard to the choice of contactless suspension systems. Each volute type was tested experimentally in a centrifugal pump test setup at various rotational speeds and flow rates. For the pump's design point at 5 L/min and 2500 rpm, the single volute had the lowest radial force (∼0 N), the circular volute yielded the highest force (∼2 N), and the double volute possessed a force of approx. 0.5 N. Results of radial force magnitude and direction were obtained and compared with a previously performed computational fluid dynamics (CFD) study.

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Effects of Tongue Position and Base Circle Diameter on the Performance of a Centrifugal Blood Pump

Cited by 15 publications

References 22 publications

Effects of Eccentric Impeller Position on Radial Passive Stability in a Magnetically Levitated Centrifugal Blood Pump with a Double Volute

Effects of Eccentric Impeller Position on Radial Passive Stability in a Magnetically Levitated Centrifugal Blood Pump with a Double Volute

Hydraulic losses in the spiral case of low specific speed pumps

Evaluation of Hydraulic Radial Forces on the Impeller by the Volute in a Centrifugal Rotary Blood Pump

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