Showing papers on "Impeller published in 2005"

Electronic component cooling apparatus

Abstract: An electronic component cooling apparatus capable of permitting a sufficient amount of air to be fed to an electronic component to be cooled An impeller which includes a plurality of blades for sucking air from one side in an axial direction of a revolving shaft of a motor is fixed on a rotor of the motor A casing having a cylindrical cavity defined therein in which the motor and impeller are received is constructed of a peripheral wall arranged so as to surround the impeller and a closing wall for closing an end of the cavity on the other side in the axial direction The peripheral wall is formed at a portion thereof in proximity to an end thereof on the one side with a lateral discharge port through which air suckedly introduced into the cavity is discharged so that a surrounding portion for surrounding a whole circumference of the impeller is left at a portion of the peripheral wall in proximity to an end on the other side The casing is provided with a spacer means for providing an interval between the casing and an opposite member

Torque transmission device

Abstract: The invention relates to a torque transmission device comprising a torque converter, a pump impeller, a turbine wheel and optionally a stator. The inventive device also comprises a converter bypass coupling having a flange (19) which is connected to the housing (6) or the pump impeller (10) in a positively engaged manner. Said flange is arranged between the pump impeller (10) and the turbine wheel (9) and can be connected to the turbine wheel (9) in a frictionally engaged manner by means of a first coupling (27).

Expandable impeller pump

Abstract: An impeller includes a hub, and a plurality of blades supported by the hub, the blades being arranged in at least two blade rows. The impeller has a deployed configuration in which the blades extend away from the hub, and a stored configuration in which at least one of the blades is radially compressed, for example by folding the blade towards the hub. The impeller may also have an operational configuration in which at least some of the blades are deformed from the deployed configuration upon rotation of the impeller when in the deployed configuration. The outer edge of one or more blades may have a winglet, and the base of the blades may have an associated indentation to facilitate folding of the blades.

Impeller for a rotary ventricular assist device

Abstract: An impeller for a blood pump such as a magnetically driven, rotary ventricular assist device for pumping blood of a patient, the impeller being substantially entirely made of an alloy which consists essentially of about 70-80 weight percent of platinum and 20-30 weight percent of cobalt.

Rotary pump with exclusively hydrodynamically suspended impeller

Abstract: A pump assembly 1, 33, 200 adapted for continuous flow pumping of blood. In a particular form the pump 1, 200 is a centrifugal pump wherein the impeller 100, 204 is entirely sealed within the pump housing 2, 201 and is exclusively hydrodynamically suspended therein as the impeller rotates within the fluid 105 urged by electromagnetic means external to the pump cavity 106, 203. Hydrodynamic suspension is assisted by the impeller 100, 204 having deformities therein such as blades 8 with surfaces tapered from the leading edges 102, 223 to the trailing edges 103, 224 of bottom and top edges 221, 222 thereof.

Hydrodynamic design of rotodynamic pump impeller for multiphase pumping by combined approach of inverse design and CFD analysis

Abstract: A combined approach of inverse method and direct flow analysis is presented for the hydrodynamic design of gas-liquid two-phase flow rotodynamic pump impeller. The geometry of impeller blades is designed for a specified velocity torque distribution by treating the two-phase mixture as a homogeneous fluid under the design condition. The three-dimensional flow in the designed impeller is verified by direct turbulent flow analysis, and the design specification is further modified to optimize the flow distribution. A helical axial pump of high specific speed has been developed. To obtain a favorable pressure distribution the impeller blade was back-loaded at the hub side compared to the tip side

Direct determination of energy dissipation in stirred vessels with two‐point LDA

Abstract: The ensemble-averaged kinetic energy viscous dissipation rate was determined with a multipoint LDA technique in a vessel stirred by a Rushton turbine. Nine out of the total of 12 mean squared velocity gradients constituting the dissipation rate were directly measured in the impeller stream, and the deviation of the flow from local isotropy was investigated. The dissipation rate normalized with N3D2, where N and D are the impeller rotational speed and the impeller diameter, respectively, was found to be approximately constant for Reynolds numbers of 20,000–40,000, whereas the fluctuating gradients were found to vary significantly, by up to three times the ensemble-averaged values, with blade angular position. The ensemble-averaged dissipation rate values were also assessed through a local turbulence kinetic energy balance. © 2005 American Institute of Chemical Engineers AIChE J, 2005

A validated computational fluid dynamics model to estimate hemolysis in a rotary blood pump.

Abstract: A major part of developing rotary blood pumps requires the optimization of hemolytic properties of the entire pump. Application of a suited computational fluid dynamics (CFD)-based hemolysis model allows approximation of blood damage in an early phase of the design process. Thus, a drastic reduction of time- and cost- intensive hemolysis experiments can be achieved. For the MicroDiagonal Pump (MDP), still under development at Helmholtz-Institute in Aachen, Germany, different pump configurations have been analyzed, both numerically and experimentally. The CFD model of the pump has been successfully validated based on the comparison of the pressure head curves (H-Q curves), as discussed in a prior publication. In the present study, the authors focus on the development of a semiempiric blood damage model using the CFD and in vitro hemolysis data. On the one hand, mean key characteristics (shear stress and exposure time) and other characteristics affecting blood damage have been calculated based on numerical data. On the other hand, in vitro hemolysis tests have been accomplished in order to determine the hemolytic curves of two different pump configurations (with the same impeller but different tip clearances). Finally, a new function based on a general power law has been defined by means of the mean key characteristics. The unknown constants of the function have been determined by multidimensional regression analysis using the hemolytic curves. For the final validation of this new blood damage model, the calculated and the in vitro obtained hemolysis indices at the specific VAD operating point have been compared for all pump configurations. The comparison showed an excellent agreement, both qualitatively and quantitatively.

Numerical Modelization of the Flow in Centrifugal Pump: Volute Influence in Velocity and Pressure Fields

Abstract: A 3D-CFD simulation of the impeller and volute of a centrifugal pump has been performed using CFX codes. The pump has a specific speed of 32 (metric units) and an outside impeller diameter of 400 mm. First, a 3D flow simulation for the impeller with a structured grid is presented. A sensitivity analysis regarding grid quality and turbulence models were also performed. The final impeller model obtained was used for a 3D quasi-unsteady flow simulation of the impeller-volute stage. A procedure for designing the volute, the nonstructured grid generation in the volute, and the interface flow passage between the impeller and volute are discussed. This flow simulation was carried out for several impeller blades and volute tongue relative positions. As a result, velocity and pressure field were calculated for different flow rates, allowing to obtain the radial thrust on the pump shaft.

Time-resolved particle imaging velocimetry for the investigation of rotating stall in a radial pump

Abstract: The operating range of turbomachines is limited in terms of the low flow rate by instabilities appearing in flow-leading parts of the machinery resulting in the creation of vortices. If the flow is further throttled, stall cells can start to propagate in the impeller at a fraction of the rotor speed. This article presents an investigation of rotating stall at different flow rates in a radial pump using time-resolved particle imaging velocimetry (PIV). This technique was used to investigate the flow field at the same position in every channel of the impeller during several revolutions. Frequency analysis was applied to the measured velocities to calculate the angular speed of the rotating stall in the impeller. The interest of time-resolved PIV to understand rotating stall is demonstrated, as it allows measurement of transient, irregularly appearing flow fields.

Molten metal pump

Abstract: A molten metal pump includes an impeller, a pump base housing at least partially enclosing the impeller, a shaft connected to the impeller, a motor connected to the shaft, a motor mount plate for supporting the motor; and a post for connecting the motor mount plate to the pump base housing. The molten metal pump can include a connector that connects the post to the motor mount plate. The molten metal pump can include a socket for connecting the shaft to the motor. The shaft can comprise an assembly including an elongated metal rod having a first end and a second end and a metal non-circular drive member attached at the second end of the elongated metal rod. The impeller can include a cap member having a plurality of generally polygonally shaped inlet openings communicating with internal passages of the impeller, each inlet opening having an inner wall and an outer wall, the outer wall being longer than the inner wall, each inlet opening also including a leading wall and a trailing wall, the leading wall and the trailing wall each interconnecting the inner wall and the outer wall and each being inclined such that an uppermost edge of each wall precedes a lowermost edge of each wall in a first rotational direction.

Experimental Investigations on Pressure Fluctuations and Vibration of the Impeller in a Centrifugal Pump with Vaned Diffusers

Abstract: The pressure fluctuations acting on the impeller and the impeller vibration excited by the fluctuations were investigated in a centrifugal pump with several vaned diffusers. Firstly, the pressures both acting on the impeller and in the volute were measured simultaneously. It was demonstrated that both the volute static pressure and the pressure fluctuations on the impeller are uneven circumferentially (not uniform) under off-design operating conditions. At high flow rates, the pressure fluctuations are large in the front of the volute exit, where the static pressure is low. Secondly, the impeller vibration excited by the fluctuations was measured. It was found that resonance can be excited even when the resonance condition of rotor-stator interaction is not satisfied and sidebands occur in frequency spectra because of the circumferential unevenness of the fluctuations. Resonance can also be excited when a natural frequency of the impeller coincides with the frequencies of sidebands. Furthermore, the vibration wave is a traveling wave in the circumferential direction when resonance of a nodal diameter mode is excited, and the resonant frequency may depend on the traveling direction of the wave due to the inertia effect (added mass) of water.

Sensorless flow estimation for implanted ventricle assist device

Abstract: A method of estimating the blood flow rate of a heart ventricle assist device which is positioned externally of, or implanted in, a patient. The assist device comprises a blood pump having a rapidly rotating, electrically powered impeller, and comprises briefly interrupting power to the impeller to cause its rotation to slow. From this, blood viscosity can be estimated, which viscosity is used to obtain real time, estimated blood flow rates and pressure heads. Apparatus for accomplishing this is disclosed.

Replaceable expandable transmyocardial ventricular assist device

Abstract: A novel ventricular assist device is disclosed comprising a pump unit and a motor unit. The pump unit is made up of an impeller, an impeller housing, and a shaft. The impeller and/or the impeller housing are expandable, allowing for custom fitting and positioning of the pump unit within the ventricle. In certain embodiments, the shaft is adjustable, allowing for further customization of fit.

Foldable Intravascularly Inserted Blood Pump

Abstract: A foldable intravascularly insertable blood pump employs an impeller with radially delivering vanes in combination with an annular deflection channel. The impeller is driven by a shaft extending through a catheter wherein the impeller and its envelope are foldable by relative displacement of the shaft and catheter.

Mixed flow artificial heart pump with axial self-bearing motor

Abstract: With the objective of developing a small blood pump with a levitated rotor, we propose a design scheme for an axial-type self-bearing motor. The axial type motor, which is basically composed of a disc motor and an axial magnetic bearing, controls both the rotation and the axial translation of the rotor. The proposed motor is similar to the bidirectional disc motor, except for changing the magnitudes of both sides of the flux to control the axial attractive force. However, the radial and tilt directions rely on passive stability, and, therefore, the rotor has poor damping which might cause damage to blood constituents. The design includes a hydrodynamic bearing for improving radial support properties. Finally, to confirm its functionality, an experimental prototype of the proposed motor has been constructed and incorporated into a mixed flow blood pump. The results indicated that the bidirectional axial-type self-bearing motor had high efficiency as a small continuous flow blood pump, delivering sufficient flow rate and pressure head.

Wet type purification apparatus utilizing a centrifugal impeller

Abstract: This invention relates to a wet type air cleaner utilizing a centrifugal impeller with an electric motor instead of using filters, thus the separation of particular dust, mist can be absolutely eliminated from air with the difference of specific gravity between gas and pollution liquid under centrifugal force An wet type air cleaner utilizing a centrifugal impeller comprising: protection grill (400) and water tank (401) located on an inlet pipe (405), an electric motor (433) with a centrifugal impeller (408) and a bearing (434) located inside of centrifugal cleaner (407), a drain trap (441) and humidity controller (442) installed on an exit pipe (432) etc Therefore centrifugal wet type air cleaner make fresh air efficiently to be carried out by centrifugal force without using filters in the field of home, office, passenger car, dust place like cement factory, machine center, exhaust gas cleaner for an industrial burner and an internal combustion engine

Numerical and Experimental Investigation of Liquid-Liquid Two-Phase Flow in Stirred Tanks

Abstract: The experimental data on the holdup of the dispersed phase in a Rushton impeller agitated stirred tank are presented. Experimental measurement is performed utilizing the sample withdrawal method to obtain the local dispersed-phase holdup in a laboratory-scale stirred tank under a variety of operating conditions. Three-dimensional turbulent two-phase liquid-liquid flow in the stirred tank is also numerically simulated by solving the Reynolds-averaged Navier-Stokes equations of two phases formulated by the two-fluid model. The turbulence effect is formulated using a simple two-phase extension of the well-known k-epsilon turbulence model by adding an extra source term generated from the presence of the dispersed phase in the turbulent kinetic energy transport equation of the continuous phase. A modified "inner-outer" iterative procedure is employed to model the interaction of the rotating impeller with the wall baffles. The model-predicted mean velocity, turbulence characteristics of the continuous phase, and holdup profiles of the dispersed phase are compared against the published experimental data and the present measurements to validate the computational procedure, and good agreement is found up to a rather high overall dispersed-phase holdup case (30 vol %).

Unsteady Hydrodynamic Forces due to Rotor-Stator Interaction on a Diffuser Pump With Identical Number of Vanes on the Impeller and Diffuser

Abstract: Experimental and computational study was developed for unsteady hydrodynamic forces on a diffuser pump impeller excited by the interaction between the impeller and the vaned diffuser with the same number of vanes as impeller. Unsteady flow calculations are made using commercially available CFD software, CFX-TASCflow, as well as the two-dimensional vortex method. Calculated pressure and fluid forces on the impeller show good agreement with measured ones. It has been demonstrated that the fluid forces on the impeller with the same number of vanes as the vaned diffuser are smaller compared with other combinations of vane numbers. However, the pressure fluctuations are found to be greater than other cases.

Gas mixing and dispersement in pumps for pumping molten metal

Abstract: A molten metal pump including a pump base with an inlet and outlet, a mixing impeller chamber for mixing gas and molten metal, a pumping impeller chamber for pumping molten metal. First and second impeller members supported by a shaft are adapted to rotate in mixing and pumping chambers respectively. The impeller members may be integrally formed of a single impeller or separate impellers on one or more shafts. A gas passageway extends from a gas source to the mixing chamber in the base. A gas dispersement pump includes a base with an impeller chamber and inlet and an outlet. An impeller is mounted to a shaft and adapted to be rotated in the impeller chamber. A gas passageway extends from a gas source to a gas outlet proximate to the impeller chamber. A gas dispersement member of porous refractory material is adapted to disperse gas from the gas passageway. In a gas dispersement and gas/molten metal mixing pump, the dispersement member disperses the gas stream entering the mixing chamber where the gas is mixed with molten metal. Molten metal is pumped in the pumping chamber. A gas/molten metal mixture is discharged from the mixing chamber and molten metal is discharged from the pumping chamber.

Multiple rotor, wide blade, axial flow pump

Abstract: A blood pump comprises a pump housing; a plurality of rotors positioned in said housing, each rotor comprising an impeller having a hydrodynamic surface for pumping blood; and a motor including a plurality of magnetic poles carried by each impeller, having motor stators, each including electrically conductive coils located adjacent to or within the housing. At least one of the rotors is adopted to rotate clockwise, and at least one of rotors is adopted to rotate counterclockwise. By this means, stator or stationary blades between the rotors may not be needed.

Numerical and Experimental Analysis of an Axial Flow Left Ventricular Assist Device: The Influence of the Diffuser on Overall Pump Performance

Abstract: Thousands of adult cardiac failure patients may benefit from the availability of an effective, long-term ventricular assist device (VAD). We have developed a fully implantable, axial flow VAD (LEV-VAD) with a magnetically levitated impeller as a viable option for these patients. This pump's streamlined and unobstructed blood flow path provides its unique design and facilitates continuous washing of all surfaces contacting blood. One internal fluid contacting region, the diffuser, is extremely important to the pump's ability to produce adequate pressure but is challenging to manufacture, depending on the complex blade geometries. This study examines the influence of the diffuser on the overall LEV-VAD performance. A combination of theoretical analyses, computational fluid (CFD) simulations, and experimental testing was performed for three different diffuser models: six-bladed, three-bladed, and no-blade configuration. The diffuser configurations were computationally and experimentally investigated for flow rates of 2-10 L/min at rotational speeds of 5000-8000 rpm. For these operating conditions, CFD simulations predicted the LEV-VAD to deliver physiologic pressures with hydraulic efficiencies of 15-32%. These numerical performance results generally agreed within 10% of the experimental measurements over the entire range of rotational speeds tested. Maximum scalar stress levels were estimated to be 450 Pa for 6 L/min at 8000 rpm along the blade tip surface of the impeller. Streakline analysis demonstrated maximum fluid residence times of 200 ms with a majority of particles exiting the pump in 80 ms. Axial fluid forces remained well within counter force generation capabilities of the magnetic suspension design. The no-bladed configuration generated an unacceptable hydraulic performance. The six-diffuser-blade model produced a flow rate of 6 L/min against 100 mm Hg for 6000 rpm rotational speed, while the three-diffuser-blade model produced the same flow rate and pressure rise for a rotational speed of 6500 rpm. The three-bladed diffuser configuration was selected over the six-bladed, requiring only an incremental adjustment in revolution per minute to compensate for and ease manufacturing constraints. The acceptable results of the computational simulations and experimental testing encourage final prototype manufacturing for acute and chronic animal studies.

Computational design and experimental testing of a novel axial flow LVAD

Abstract: Thousands of cardiac failure patients per year in the United States could benefit from long-term mechanical circulatory support as destination therapy. To provide an improvement over currently available devices, we have designed a fully implantable axial-flow ventricular assist device with a magnetically levitated impeller (LEV-VAD). In contrast to currently available devices, the LEV-VAD has an unobstructed blood flow path and no secondary flow regions, generating substantially less retrograde and stagnant flow. The pump design included the extensive use of conventional pump design equations and computational fluid dynamics (CFD) modeling for predicting pressure-flow curves, hydraulic efficiencies, scalar fluid stress levels, exposure times to such stress, and axial fluid forces exerted on the impeller for the suspension design. Flow performance testing was completed on a plastic prototype of the LEV-VAD for comparison with the CFD predictions. Animal fit trials were completed to determine optimum pump location and cannulae configuration for future acute and long-term animal implantations, providing additional insight into the LEVVAD configuration and implantability. Per the CFD results, the LEV-VAD produces 6 l/min and 100 mm Hg at a rotational speed of approximately 6300 rpm for steady flow conditions. The pressure-flow performance predictions demonstrated the VAD’s ability to deliver adequate flow over physiologic pressures for reasonable rotational speeds with best efficiency points ranging from 25% to 30%. The CFD numerical estimations generally agree within 10% of the experimental measurements over the entire range of rotational speeds tested. Animal fit trials revealed that the LEV-VAD’s size and configuration were adequate, requiring no alterations to cannulae configurations for future animal testing. These acceptable performance results for LEV-VAD design support proceeding with manufacturing of

Elimination of adverse leakage flow in a miniature pediatric centrifugal blood pump by computational fluid dynamics-based design optimization.

Abstract: We investigated a miniature magnetically levitated centrifugal blood pump intended to deliver 0.3-1.5 l/min of support to neonates and infants. The back clearance gap between the housing and large volume of the rotor, where the suspension and motor bearings are located, forms a continuous leakage flow path. Within the gap, flow demonstrates a very complex three-dimensional structure: the fluid adjacent to the rotating disk tends to accelerate by centrifugal force to flow radially outwards toward the outlet of the impeller against an unfavorable pressure gradient, which in turn forces blood to return along the stationary housing surfaces. Consequently, one or multiple vortices may be generated in the gap to block blood flow and cause the formation of a retrograde and antegrade leakage flow phenomenon at the gap outlet using an optimization process including extensive computational fluid dynamics (CFD) analysis of impeller refinements, we found that secondary blades located along the back or extended to the side surfaces of the rotor have the capacity to reduce and eliminate the retrograde flow in the back clearance gap. Flow visualization confirmed the CFD-predicted flow patterns. This work demonstrates the utility of CFD-based design optimization to optimize the fluid path of a miniature centrifugal pump.

Integrated fluid power conversion system

Abstract: A fluid power conversion apparatus serving fluid pumping and/or power-generation functions, comprising: an impeller having an impeller hub and a periphery; a housing around the impeller; a diffusor having (a) an outer wall attached to the housing, (b) a diffusor hub rotatably supporting the impeller, and (c) at least one stator vane securing the diffusor hub to the outer wall; and a rotating electrical machine having (a) an armature attached to the housing and (b) a rotor attached to the impeller periphery and positioned to form a rotor-armature gap, whereby the impeller and the rotor form an integrated unit with fluid flow through the rotor.