The current research of the valveless piezoelectric pump focuses on increasing the flow rate and pressure differential. Compared with the valve piezoelectric pump, the valveless one has excellent performances in simpl...The current research of the valveless piezoelectric pump focuses on increasing the flow rate and pressure differential. Compared with the valve piezoelectric pump, the valveless one has excellent performances in simple structure, low cost, and easy miniaturization. So, their important development trend is the mitigation of their weakness, and the multi-function integration. The flow in a spiral tube element is sensitive to the element attitude caused by the Coriolis force, and that a valveless piezoelectric pump is designed by applying this phenomenon. The pump has gyroscopic effect, and has both the actuator function of fluid transfer and the sensor function, which can obtain the angular velocity when its attitude changes. First, the present paper analyzes the flow characteristics in the tube, obtains the calculation formula for the pump flow, and identifies the relationship between pump attitude and flow, which clarifies the impact of flow and driving voltage, frequency, spiral line type and element attitude, and verifies the gyroscopic effect of the pump. Then, the finite element simulation is used to verify the theory. Finally, a pump is fabricated for experimental testing of the relationship between pump attitude and pressure differential. Experimental results show that when Archimedes spiral θ=4π is selected for the tube design, and the rotation speed of the plate is 70 r/min, the pressure differential is 88.2 Pa, which is 1.5 times that of 0 r/min rotation speed. The spiral-tube-type valveless piezoelectric pump proposed can turn the element attitude into a form of pressure output, which is important for the multi-function integration of the valveless piezoelectric pump and for the development of civil gyroscope in the future.展开更多
From 1997 to 1999, we developed a spiral blood pump. The spiral pump consists of a brushless DC motor, the pump housing, a magnetic-fluid seal, bearings and a spiral impeller. The maximum diameter of the impeller is 2...From 1997 to 1999, we developed a spiral blood pump. The spiral pump consists of a brushless DC motor, the pump housing, a magnetic-fluid seal, bearings and a spiral impeller. The maximum diameter of the impeller is 21.8 mm and minimum is 9.8 mm, the cone angle of the impeller threads is 41.8 degrees. The housing has a maximum diameter of 30 mm. The pump was made from Titanium alloy, the total volume of pump housing and motor was 76 ml and its weight 220g. Methods used: The hydrodynamic performance of the spiral pump was examined from 8 000 to 10 000rpm rotation speeds in a closed circuit loop. This circuit consists of a reservoir, a clamp, two pressure transducers, an electric-magnetic flow rate transducer and glycerin-water solution. The damage test to blood was studied in a smaller circuit loop, that used fresh sheep blood and polyvinyl chloride bag instead of the glycerin-water solution and the reservoir. In this test, the damage of the spiral pump was compared with an axial flow blood pump. Furthermore the simulated condition was 5.0 L/ min flow rate and 100 mmHg pressure. Summarize Results: 1. The flow rate was 4.0 L/min against 120 mmHg pressure when pump rotated 10000 rpm. So the hydrodynamic performance of the spiral blood pump was enough to meet a patient’s need when the blood pump was used as a left ventricular assistant device. 2. The NIH results of three gaps were 0.074±0.022g/100L,0.086±.026g/100L and 0.111±0.034g/100L(n=40) respectively. The best hemolysis result was been at the gap of 0.14 mm. 3. The NIH result of the spiral pump with 0.40gap was 0.111±0.034g/100L, n=40; and the axial flow pump was 0.131±0.030g/100L, n=40 respectively; The mean fibrinogen decreases of two pumps between half of an hour were 4.281±2.098mg/100L and 9.625±5.630mg/100L(n=40). So we can conclude that the damage of the spiral pump to blood was less than the axial flow pump. (P<0.05).展开更多
The current research of hydrodynamic bearing in blood pump mainly focuses on the bearing structure design.Compared with the typical plane slider bearing and Rayleigh step bearing,spiral groove bearing has excellent pe...The current research of hydrodynamic bearing in blood pump mainly focuses on the bearing structure design.Compared with the typical plane slider bearing and Rayleigh step bearing,spiral groove bearing has excellent performance in load-carrying capacity.However,the load-carrying capacity would decrease significantly with increasing flow rate in conventional designs.In this paper,the special treatment is made to the upper spiral groove bearing to make sure that both the circulatory flowing and load-carrying capacity are high.Three-dimensional computational fluid dynamics(CFD) models in the space between rotor and shaft are developed by using FLUENT software.Effects of groove number,film height and groove depth on load-carrying capacity of the spiral groove bearings are investigated by orthogonal experiment design.The experimental results show that film height is the most remarkable factor to the load-carrying capacity.The variation tendency of load-carrying capacity reveals that the best combination of geometry is the one with groove number of 8,film height 0.03 mm and groove depth 0.08 mm.The velocity and pressure distributions in spiral groove bearings are also analyzed,and the analysis result shows that the distributions are in conformity with the design of the blood pump based on the principle of hydrodynamic bearing.The displacement of the rotor with the best combination parameters is tested by using laser displacement sensors,the testing result shows that the suspending performance is satisfactory both in axial and radial directions.This research proposes a bearing design method which has sufficient load-carrying capacity to support rotor as an effective passive hydrodynamic bearing.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51075201,51205193,51375227)
文摘The current research of the valveless piezoelectric pump focuses on increasing the flow rate and pressure differential. Compared with the valve piezoelectric pump, the valveless one has excellent performances in simple structure, low cost, and easy miniaturization. So, their important development trend is the mitigation of their weakness, and the multi-function integration. The flow in a spiral tube element is sensitive to the element attitude caused by the Coriolis force, and that a valveless piezoelectric pump is designed by applying this phenomenon. The pump has gyroscopic effect, and has both the actuator function of fluid transfer and the sensor function, which can obtain the angular velocity when its attitude changes. First, the present paper analyzes the flow characteristics in the tube, obtains the calculation formula for the pump flow, and identifies the relationship between pump attitude and flow, which clarifies the impact of flow and driving voltage, frequency, spiral line type and element attitude, and verifies the gyroscopic effect of the pump. Then, the finite element simulation is used to verify the theory. Finally, a pump is fabricated for experimental testing of the relationship between pump attitude and pressure differential. Experimental results show that when Archimedes spiral θ=4π is selected for the tube design, and the rotation speed of the plate is 70 r/min, the pressure differential is 88.2 Pa, which is 1.5 times that of 0 r/min rotation speed. The spiral-tube-type valveless piezoelectric pump proposed can turn the element attitude into a form of pressure output, which is important for the multi-function integration of the valveless piezoelectric pump and for the development of civil gyroscope in the future.
基金The project was support by National Nine- Five Years Foundation
文摘From 1997 to 1999, we developed a spiral blood pump. The spiral pump consists of a brushless DC motor, the pump housing, a magnetic-fluid seal, bearings and a spiral impeller. The maximum diameter of the impeller is 21.8 mm and minimum is 9.8 mm, the cone angle of the impeller threads is 41.8 degrees. The housing has a maximum diameter of 30 mm. The pump was made from Titanium alloy, the total volume of pump housing and motor was 76 ml and its weight 220g. Methods used: The hydrodynamic performance of the spiral pump was examined from 8 000 to 10 000rpm rotation speeds in a closed circuit loop. This circuit consists of a reservoir, a clamp, two pressure transducers, an electric-magnetic flow rate transducer and glycerin-water solution. The damage test to blood was studied in a smaller circuit loop, that used fresh sheep blood and polyvinyl chloride bag instead of the glycerin-water solution and the reservoir. In this test, the damage of the spiral pump was compared with an axial flow blood pump. Furthermore the simulated condition was 5.0 L/ min flow rate and 100 mmHg pressure. Summarize Results: 1. The flow rate was 4.0 L/min against 120 mmHg pressure when pump rotated 10000 rpm. So the hydrodynamic performance of the spiral blood pump was enough to meet a patient’s need when the blood pump was used as a left ventricular assistant device. 2. The NIH results of three gaps were 0.074±0.022g/100L,0.086±.026g/100L and 0.111±0.034g/100L(n=40) respectively. The best hemolysis result was been at the gap of 0.14 mm. 3. The NIH result of the spiral pump with 0.40gap was 0.111±0.034g/100L, n=40; and the axial flow pump was 0.131±0.030g/100L, n=40 respectively; The mean fibrinogen decreases of two pumps between half of an hour were 4.281±2.098mg/100L and 9.625±5.630mg/100L(n=40). So we can conclude that the damage of the spiral pump to blood was less than the axial flow pump. (P<0.05).
基金supported by National Natural Science Foundation of China(Grant No.51275461)Zhejiang Provincial Natural Science Foundation of China(Grant No.Z1110189)+1 种基金National Hi-tech Research and Development Program of China(863 ProgramGrant No.2009AA045401)
文摘The current research of hydrodynamic bearing in blood pump mainly focuses on the bearing structure design.Compared with the typical plane slider bearing and Rayleigh step bearing,spiral groove bearing has excellent performance in load-carrying capacity.However,the load-carrying capacity would decrease significantly with increasing flow rate in conventional designs.In this paper,the special treatment is made to the upper spiral groove bearing to make sure that both the circulatory flowing and load-carrying capacity are high.Three-dimensional computational fluid dynamics(CFD) models in the space between rotor and shaft are developed by using FLUENT software.Effects of groove number,film height and groove depth on load-carrying capacity of the spiral groove bearings are investigated by orthogonal experiment design.The experimental results show that film height is the most remarkable factor to the load-carrying capacity.The variation tendency of load-carrying capacity reveals that the best combination of geometry is the one with groove number of 8,film height 0.03 mm and groove depth 0.08 mm.The velocity and pressure distributions in spiral groove bearings are also analyzed,and the analysis result shows that the distributions are in conformity with the design of the blood pump based on the principle of hydrodynamic bearing.The displacement of the rotor with the best combination parameters is tested by using laser displacement sensors,the testing result shows that the suspending performance is satisfactory both in axial and radial directions.This research proposes a bearing design method which has sufficient load-carrying capacity to support rotor as an effective passive hydrodynamic bearing.
文摘为研究旋壳转速对腔内液体流动特性的影响,以试验旋喷泵为研究对象,在高度验证叶轮与旋壳同步旋转试验与模拟结果准确性的基础上,对叶轮转速相同、旋壳转速不同的5个模型采用RNG k-ε湍流模型进行数值计算,分析腔内液体流动特性的变化情况,研究泵的性能.结果表明:旋壳转速增大,液体圆周速度和旋转系数均增大,圆周速度曲线沿径向逐渐形成同心圆,腔内液体做非刚性旋转.腔内液体径向压力梯度增大,压力低于624 kPa时,旋壳转速越高,压力越小;压力高于624 kPa时,旋壳转速越高,压力越大.集流管迎流区涡分布在进口附近,尾迹区涡集中在扩散段结尾处,整体呈增大趋势.旋壳转速增大,泵的扬程升高,但效率降低,通过改变集流管进口直径发现集流管并非效率降低的主要原因,而是由圆盘摩擦损失的增大导致的,圆盘摩擦损失随旋壳转速增加呈3次幂函数式增大,文中最优进口直径为13 mm.
