Through the laboratory flow experiments with aqueous solution of varied consistency of HPAM ,the average flow rates calculated with the theoretical formulae are compared with those meassured in the experiments , and it shows that the numerical method of the unsteady flow of power-law fluid in eccentric annuli with the inner cylinder reciprocating axially in the paper is correct.

Through the laboratory flow experiments with aqueous solution of varied consistency of HPAM ,the average flow rates calculated with the theoretical formulae are compared with those meassured in the experiments , and it shows that the numerical method of the unsteady flow of power-law fluid in eccentric annuli with the inner cylinder reciprocating axially in the paper is correct.

The basic equations of the unsteady flow of second order fluid with variable coefficients in the eccentric annuli with inner cylinder reciprocating axially in rectangular and bipolar coordinate are established respectively in this paper, and the formula of normal stress on the inner cylinder is given.

The governing equations, initial and boundary condition equations, and instantaneous flow rate formula of unsteady flow of the Newtonian fluid in eccentric annuli with the inner cylinder reciprocating axially in bipolar coordinate system are established in this paper.

By the numerical calculation of the equations of motion, the velocity distribution, the instantaneous flow rate distribution, the average flow and the normal stress distribution on the inner cylinder of second order fluid with variable coefficients in the eccentric annuli with inner cylinder reciprocating axially are obtained;

A pulsatile axial pump and a pulsatile centrifugal pump are developed. The pulsatile flow of impeller pump is discussed. In the pulsatile axial pump, the impeller reciprocates axially and rotates simultaneously. The reciprocation is driven by a pneumatic device and the rotation by a DC motor. FOr 5.3 kPa pulsatility of pressure, about 50 mm axial reciprocatiDg amplitude of the impeller is desirable. In order to reduce the axial amplitude, the pump inlet and the impeller both have cone -shaped heads, and...

A pulsatile axial pump and a pulsatile centrifugal pump are developed. The pulsatile flow of impeller pump is discussed. In the pulsatile axial pump, the impeller reciprocates axially and rotates simultaneously. The reciprocation is driven by a pneumatic device and the rotation by a DC motor. FOr 5.3 kPa pulsatility of pressure, about 50 mm axial reciprocatiDg amplitude of the impeller is desirable. In order to reduce the axial amplitude, the pump inlet and the impeller both have cone -shaped heads, and the gap between the impeller and the inlet pipe changes only 2 mm, namely, the impeller reciprocates 2 mm, a pressure pulsatility of 5.3 kPa can be produced. As the impeller rotates with constant speed, low turbulence in axial pthsatile pump may be expected. In centrifugal pulsatile PumP, the impeller changes its rotating speed periodically; the turbulence is reduced by designing an impeller with twisted vanes which enable the blood flow to change its direction rather than its magnitude during the periodic change of the rotating speed. In this way, a pulsatile flow is prepuced and the turbulence has been minimized. Compared to the axial pulsatile pump, the centrifugal pulsatile pump needs only one driver and thus has more reality for application. The centrifugal pulsatile pump is used in animal experiments. The pump assisted the circulation of the calves for several months without harm to the blood elements and the organ functions of the experimental animal. The experimentS demonstrated furthermore that the pulsatile impeller pump is the most efficient assist pump for heart recovery.

The governing equations of unsteady flow of nonNewtonian fluid in eccentric annuli with the inner cylinder reciprocating axially expressed in bipolar coordinate system are established in this paper.The equations are solved numerically in finite difference method for aqueous solution of HPAM and the curves of velocity distribution are plotted.The effects of the excentricity between the inner cylinder and the outer cylinder, the stroke and frequency of the inner cylinder on the velocity distribution of...

The governing equations of unsteady flow of nonNewtonian fluid in eccentric annuli with the inner cylinder reciprocating axially expressed in bipolar coordinate system are established in this paper.The equations are solved numerically in finite difference method for aqueous solution of HPAM and the curves of velocity distribution are plotted.The effects of the excentricity between the inner cylinder and the outer cylinder, the stroke and frequency of the inner cylinder on the velocity distribution of the fluid in eccentric annuli are analyzed.The results show that velocity distribution in the widest clearance is close to that in the narrowest clearance with the excentricity decreasing, and that the perturbation of velocity distribution is aggravated with the stroke and frequency increasing, which is caused by the inner cylinder reciprocating axially.

For long-term application of the rotary pumps, it is necessary to solve the problems of bearing wear and thrombosis along the bearing. Currently, many investigators choose the magnetic bearing to realize zero-friction and no contact between the rotor and stator; the former avoids the mechanical wear and the latter eliminates the possibility of thrombus formation. We tried and found that it is difficult to apply a magnetic bearing to rotary pump without disturbing its simplicity, reliability and implantability;...

For long-term application of the rotary pumps, it is necessary to solve the problems of bearing wear and thrombosis along the bearing. Currently, many investigators choose the magnetic bearing to realize zero-friction and no contact between the rotor and stator; the former avoids the mechanical wear and the latter eliminates the possibility of thrombus formation. We tried and found that it is difficult to apply a magnetic bearing to rotary pump without disturbing its simplicity, reliability and implantability; therefore, we have developed a much simpler and much more creative approach to achieving the same results.Instead of the sliding bearing, a rolling bearing has been devised for the pump; its friction is about 1/15 of the sliding bearing. Furthermore, a wear-proof material of ultra-high-molecular weight polythene has been adopted in making the rollers, their anti-wear property is 8 times better than that of metal. Thereby, the service life of the bearing has extended to several years. For preventing the thrombus formation along the bearing, the impeller reciprocates axially as the impeller changes its rotating speed periodically to produce a pulsatile flow. The reciprocation is a result of the effects of a magnetic force between the motor rotor and stator, and a hydraulic force between the blood flow and the impeller. Similar to piston pump, the oscillating impeller can make the blood in and out of the bearing, resulting in wash-out once a circle. This is obviously beneficial to preventing thrombosis along the bearing and in the pump.The endurance tests with saline of this novel pump demonstrated a durability of the device. It promises to be able to assist the circulation of the patients permanently and to be able to replace the heart transplantation in the future.