Tau Meng Lim

Nanyang Technological University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Leok Poh Chua

Nanyang Technological University

Guoliang Song

Chinese Academy of Sciences

Shanbao Cheng

TechnipFMC (United States)

Tongming Zhou

University of Western Australia

S. C. M. Yu

Hong Kong Polytechnic University

Dongsheng Zhang

Civil Aviation University of China

Boyang Su

Hong Kong Polytechnic University

Mong King Lim

Nanyang Technological University

Dongsheng Zhang

Shandong First Medical University

Guoliang Song

Ministry of Natural Resources

Cooperative Institutions

Nanyang Technological University

National University of Singapore

Chinese Academy of Sciences

Hong Kong Polytechnic University

Nanyang Polytechnic

University of Chinese Academy of Sciences

Institute of Engineering Thermophysics

Nanyang Institute of Technology

University of Western Australia

Fudan University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Parameter Estimation and Actuator Characteristics of Hybrid Magnetic Bearings for Axial Flow Blood Pump Applications

Artificial Organs (2009)

Tau Meng Lim Shanbao Cheng Leok Poh Chua

Abstract Axial flow blood pumps are generally smaller as compared to centrifugal pumps. This is very beneficial because they can provide better anatomical fit in the chest cavity, as well as lower the risk of infection. This article discusses the design, levitated responses, and parameter estimation of the dynamic characteristics of a compact hybrid magnetic bearing (HMB) system for axial flow blood pump applications. The rotor/impeller of the pump is driven by a three‐phase permanent magnet brushless and sensorless motor. It is levitated by two HMBs at both ends in five degree of freedom with proportional–integral–derivative controllers, among which four radial directions are actively controlled and one axial direction is passively controlled. The frequency domain parameter estimation technique with statistical analysis is adopted to validate the stiffness and damping coefficients of the HMB system. A specially designed test rig facilitated the estimation of the bearing's coefficients in air—in both the radial and axial directions. Experimental estimation showed that the dynamic characteristics of the HMB system are dominated by the frequency‐dependent stiffness coefficients. By injecting a multifrequency excitation force signal onto the rotor through the HMBs, it is noticed in the experimental results the maximum displacement linear operating range is 20% of the static eccentricity with respect to the rotor and stator gap clearance. The actuator gain was also successfully calibrated and may potentially extend the parameter estimation technique developed in the study of identification and monitoring of the pump's dynamic properties under normal operating conditions with fluid.

Magnetic bearing

Axial Compressor

SIGNAL (programming language)

10.1111/j.1525-1594.2009.00732.x

Cite

Citations (7)

Magnetic levitation of a one DOF system using simultaneous actuation and displacement sensing technique

Mechatronics (2011)

Tau Meng Lim Shanbao Cheng

Duty cycle

Observer (physics)

Air gap (plumbing)

Magnetic Levitation

Feedthrough

Magnetic bearing

10.1016/j.mechatronics.2011.01.007

Cite

Citations (12)

Development of Lorentz Force‐Type Self‐bearing Motor for an Alternative Axial Flow Blood Pump Design

Artificial Organs (2006)

Tau Meng Lim Dongsheng Zhang

Abstract: A Lorentz force‐type self‐bearing motor was developed to provide delivery of both motoring torque and levitation force for an alternative axial flow blood pump design with an enclosed impeller. The axial flow pumps currently available introduce electromagnetic coupling from the motor’s stator to the impeller by means of permanent magnets (PMs) embedded in the tips of the pump’s blades. This design has distinct disadvantages, for example, pumping efficiency and electromagnetic coupling transmission are compromised by the constrained or poor geometry of the blades and limited pole width of the PMs, respectively. In this research, a Lorentz force‐type self‐bearing motor was developed. It is composed of (i) an eight‐pole PM hollow‐cylindrical rotor assembly supposedly to house and enclose the impeller of an axial flow blood pump, and (ii) a six‐pole stator with two sets of copper wire and different winding configurations to provide the motoring torque and levitating force for the rotor assembly. MATLAB’s xPC Target interface hardware was used as the rapid prototyping tool for the development of the controller for the self‐bearing motor. Experimental results on a free/simply supported rotor assembly validated the design feasibility and control algorithm effectiveness in providing both the motoring torque and levitation force for the rotor. When levitated, a maximum orbital displacement of 0.3 mm corresponding to 1050 rpm of the rotor was measured by two eddy current probes placed in the orthogonal direction. This design has the advantage of eliminating the trade‐off between motoring torques, levitating force, and pumping efficiency of previous studies. It also indicated the benefits of enclosed‐impeller design as having good dynamic response, linearity, and better reliability. The nonmechanical contact feature between rotating and stationary parts will further reduce hemolysis and thromboembolitic tendencies in a typical blood pump application.

Axial-flow pump

Lorentz force

10.1111/j.1525-1594.2006.00224.x

Cite

Citations (13)

Parameter estimation and statistical analysis on frequency-dependent active control forces

Mechanical Systems and Signal Processing (2006)

Tau Meng Lim Shanbao Cheng

Magnetic bearing

Harmonic

Electromagnetic suspension

10.1016/j.ymssp.2006.09.005

Cite

Citations (20)

Control of Lorentz force-type self-bearing motors with hybrid PID and robust model reference adaptive control scheme

Mechatronics (2007)

Tau Meng Lim Dongsheng Zhang

10.1016/j.mechatronics.2007.07.007

Cite

Citations (14)

Numerical Analysis of the Inner Flow Field of a Biocentrifugal Blood Pump

Artificial Organs (2006)

Leok Poh Chua Guoliang Song Tau Meng Lim Tongming Zhou

Implantable ventricular assist devices have been regarded as a promising instrument in the clinical treatment of patients with severe heart failures. In this article, a three-dimensional model of the Kyoto-NTN magnetically suspended centrifugal blood pump was generated and a computational fluid dynamics solution of the inner flow field of the pump including the static pressure distributions, velocity profiles, and the shear stress distributions of the blood was presented. The results revealed that reverse flow generally occurred in the impeller blade channels during the operation of the pump, due to the imbalance of the flow and the pressure gradient generated in the blade channels. The flow pattern at the exit of the blade channels was varying with its angular positions in the pump. The reverse flow at the exit of the impeller blade channels was found to be closely related with the static pressure distribution in the volute passage. Higher pressure in the volute caused severe backflow from the volute into the blade channels. To clarify the effects of a moving impeller on the blood, shear stresses of the blood in the pump were investigated according to the simulation results. The studies indicated that at the beginning of the splitter plate and the cutwater, the highest shear stress exceeded 700 Pa. At other regions such as the inlet and outlet of the impeller blade channels and some regions in the volute passage, shear stresses were found to be about 200 Pa. These areas are believed to have a high possibility of rendering blood trauma.

10.1111/j.1525-1594.2006.00243.x

Cite

Citations (24)

Numerical study of the flow characteristics of Kyoto-NTN magnetically suspended centrifugal blood pump

2005 Summer Bioengineering Conference (2005)

Leok Poh Chua Guoliang Song S. C. M. Yu Tau Meng Lim

Source

Cite

Citations (0)

Design and parameter estimation of hybrid magnetic bearings for blood pump applications

Mechanical Systems and Signal Processing (2009)

Tau Meng Lim Dongsheng Zhang Juanjuan Yang Shanbao Cheng Sze Hsien Low

Magnetic bearing

10.1016/j.ymssp.2009.03.012

Cite

Citations (22)

Numerical Simulation of an Axial Blood Pump

Artificial Organs (2007)

Leok Poh Chua Boyang Su Tau Meng Lim Tongming Zhou

Abstract: The axial blood pump with a magnetically suspended impeller is superior to other artificial blood pumps because of its small size. In this article, the distributions of velocity, path line, pressure, and shear stress in the straightener, the rotor, and the diffuser of the axial blood pump, as well as the gap zone were obtained using the commercial software, Fluent (version 6.2). The main focus was on the flow field of the blood pump. The numerical results showed that the axial blood pump could produce 5.14 L/min of blood at 100 mm Hg through the outlet when rotating at 11 000 rpm. However, there was a leakage flow of 1.06 L/min in the gap between the rotor cylinder and the pump housing, and thus the overall flow rate the impeller could generate was 6.2 L/min. The numerical results showed that 75% of the scalar shear stresses (SSs) were less than 250 Pa, and 10% were higher than 500 Pa within the whole pump. The high SS region appeared around the blade tip where a large variation of velocity direction and magnitude was found, which might be due to the steep angle variation at the blade tip. Because the exposure time of the blood cell at the high SS region within the pump was relatively short, it might not cause serious damage to the blood cells, but the improvement of blade profile should be considered in the future design of the axial pump.

Axial-flow pump

Axial piston pump

Diffuser (optics)

10.1111/j.1525-1594.2007.00422.x

Cite

Citations (44)

Numerical Study of a Bio‐Centrifugal Blood Pump With Straight Impeller Blade Profiles

Artificial Organs (2009)

Guoliang Song Leok Poh Chua Tau Meng Lim

Computational fluid dynamic simulations of the flow in the Kyoto-NTN (Kyoto University, Kyoto, Japan) magnetically suspended centrifugal blood pump with a 16-straight-bladed impeller were performed in the present study. The flow in the pump was assumed as unsteady and turbulent, and blood was treated as a Newtonian fluid. At the impeller rotating speed of 2000 rpm and flow rate of 5 L/min, the pump produces a pressure head of 113.5 mm Hg according to the simulation. It was found that the double volute of the pump has caused symmetrical pressure distribution in the volute passages and subsequently caused symmetrical flow patterns in the blade channels. Due to the tangentially increasing pressure in the volute passages, the flow through the blade channels initially increases at the low-pressure region and then decreases due to the increased pressure. The reverse flow and vortices have been identified in the impeller blade channels. The high shear stress of the flow in the pump mainly occurred at the inlet and outlet of the blade channels, the beginning of the volute passages and the regions around the tips of the cutwater and splitter plate. Higher shear stress is obtained when the tips of the cutwater and splitter plate are located at the impeller blade trailing edges than when they are located at the middle of the impeller blade channel. It was found that the blood damage index assessed based on the blood corpuscle path tracing of the present pump was about 0.94%, which has the same order of magnitude as those of the clinical centrifugal pumps reported in the literature.

Volute

Slip factor

Rotodynamic pump

Specific speed

10.1111/j.1525-1594.2009.00756.x

Cite

Citations (16)