V.chong

Nanyang Technological University, Tumasik, Singapore

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Publications (3)3.48 Total impact

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    ABSTRACT: This paper describes the performance characterization of an axial blood pump that is developed in our laboratory. Using computational fluid dynamics (CFD), regions of flow separation and high shear stress were identified since they are of concern in the development of cardiac assist devices. CFD is an efficient and cost effective tool in assisting the designer to reduce the number of experimental trials needed. Preliminary CFD studies showed the existence of substantial backflow in the impeller passage. The impeller geometry was improved using CFD modeling. Regions of flow separation were eliminated while regions of scalar stress of up to 150 Pa were observed near to the impeller tip. The final prototype can deliver a flow rate of 5 L/min at a pressure head of 14 kPa when operating at a speed of 10,000 rpm. The model was fabricated using rapid prototyping techniques and performance characterization of the pump has demonstrated that the CFD prediction of the pump performance curve and the pressure developed along the impeller agrees reasonably well with experimental results.
    Journal of Mechanics in Medicine and Biology 11/2011; 05(01). · 0.76 Impact Factor
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    ABSTRACT: This paper presents preliminary results of hydraulic performance characterization of an axial blood pump. Two sets of inducer-impellers and 3 diffusers were designed and tested in a closed loop flow circuit. The results showed that the impellers tested can deliver 5 L/min at a head of 100 mmHg when operating at a rotational speed of 10,000 rpm. Based on the preliminary experiments, the double start inducer-impeller with the 100° wrap angle diffuser offers the greatest promise. However, regions of flow reversals and stagnation were noted from CFD simulations of the pump. The blade profile as well as the diffuser design has to be modified in further work to eliminate regions of flow reversals.
    Journal of Mechanics in Medicine and Biology 11/2011; 04(03). · 0.76 Impact Factor
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    ABSTRACT: A series of numerical models are generated to investigate the flow characteristics and performance of an axial blood pump. The pump model includes a straightener, an inducer-impeller, and diffuser. Numerical studies of the effects of angular alignment of the inducer and impeller blades and the axial clearance gap between the inducer and impeller are presented in this article. The pump characteristics derived from numerical simulation are validated with experimental data. Numerically simulated results showed a sinusoidal variation in the pressure generated across the pump with changes in angular alignment between the inducer and impeller. This is attributed to additional losses when flow is forced or diverted from the trailing edge of the inducer to either the pressure or suction side of the impeller blade when the alignment between the two sets of blades is not optimal. The pressure generated is a maximum when the impeller blades are at 0 or 30 degrees with respect to the inducer. The effect of rotating the impeller with respect to the inducer causes the sinusoidal pressure variation. In addition, it was observed that when the clearance gap between the inducer and impeller is reduced to 1 mm, the pressure generated is a minimum when compared to the other models. This is attributed to the interference between the inducer and impeller when the gap separating them is too small. The location of the maximum pressure on the pressure side of the impeller blade shifts upstream while its magnitude decreases for small clearance gap between the inducer and the impeller. There was no flow separation in the inducer while small regions of backflow are observed at the impeller trailing edge. Recommendations for future modifications and improvements to the pump design and model simulation are also given.
    Artificial Organs 04/2005; 29(3):250-8. · 1.96 Impact Factor

Publication Stats

7 Citations
3.48 Total Impact Points

Institutions

  • 2005–2011
    • Nanyang Technological University
      • School of Mechanical and Production Engineering
      Tumasik, Singapore