This paper presents the design, fabrication, and experimental characterization of a peristaltic micropump. The micropump is composed of two layers fabricated from Polydimethylsiloxane （PDMS） material. The first laye...This paper presents the design, fabrication, and experimental characterization of a peristaltic micropump. The micropump is composed of two layers fabricated from Polydimethylsiloxane （PDMS） material. The first layer has a rectangular channel and two valve seals. Three rectangular mini lightweight piezo-composite actuators are integrated in the second layer, and used as actuation parts. Two layers are bonded, and covered by two Polymethyl Methacrylate （PMMA） plates, which help increase the stiffness of the micropump. A maximum flow rate of 900μL.min 1 and a maximum backpressure of 1.8 kPa are recorded when water is used as pump liquid. We measured the power consumption of the micropump. The micropump is found to be a promising candidate for bio-medical application due to its bio-compatibility, portability, bidirectionality, and simple effective design.展开更多
This paper employs the integral-averaged method of thickness to approximate the periodical flows in a piezoelectric micropump, with a shallow water equation including nonlinearity and viscous damp presented to charact...This paper employs the integral-averaged method of thickness to approximate the periodical flows in a piezoelectric micropump, with a shallow water equation including nonlinearity and viscous damp presented to characterize the flows in micropump. The finite element method is used to obtain a matrix equation of fluid pressure. The fluid pressure equation is combined with the vibration equation of a silicon diaphragm to construct a liquid-solid coupled equation for reflecting the interaction between solid diaphragm and fluid motion in a micropump. Numerical results of a mode analysis of the coupled system indicate that the natural frequencies of the coupled system are much lower than those of the non-coupled system. The influence of additional mass and viscous damp of fluid on the natural frequencies of the coupled system is more significant as the pump thickness is small. It is found that the vibration shape functions of silicon diaphragm of the coupled system are almost the same as those of the non-coupled system. This paper also gives the first-order amplitude-frequency relationship of the silicon diaphragm, which is necessary for the flow-rate-frequency analysis of a micropump.展开更多
According to the'elastic buffer mechanism'and the'variable gap mechanism',a new device,which is both micropump and active microvalve actuated by PZT bimorph cantilever,was fabricated with polydimethyis...According to the'elastic buffer mechanism'and the'variable gap mechanism',a new device,which is both micropump and active microvalve actuated by PZT bimorph cantilever,was fabricated with polydimethyisiloxane (PDMS) and silicon chip.The thickness of the micropump membrance is about 180μm.The diameter and the depth of micropump chamber cavity are 6 mm and 40μm,respectively.The performances of the micropump,such as pump rate and backpressure,were characterized.As a flow-rectifying element,the diffusers and active valve were used instead of passive check valves.The flow rate and the backpressure of the micropump are about 420μL/min and 2 kPa when applying a 100 V square wave driving voltage at frequency of 35 Hz.展开更多
In this paper,we propose a new prototype model of a micro pump using ICPF(Ionic Conducting Polymer Film)actuator as the servo actuator.This micro pump consists of two active one- way valves that make use of the same I...In this paper,we propose a new prototype model of a micro pump using ICPF(Ionic Conducting Polymer Film)actuator as the servo actuator.This micro pump consists of two active one- way valves that make use of the same ICPF actuator.The overall size of this micro pump prototype is 12mm in diameter and 20mm in length.The actuating mechanism is as follows:(1)The ICPF actuator as the diaphragm is bent into anode side by application of electricity.Then the volume of the pump chamber increases,resulting in the inflow of liquid from the inlet to the chamber.(2)By changing the current direction,the volume of the pump chamber decreases,resulting in the liquid flow from the chamber to the outlet.(3)The ICPF actuator is put on a sine voltage,the micro pump provides liquid flow from the inlet to the outlet continuously.Characteristic of the micro pump is measured.The experimental results indicate that the micro pump has the satisfactory responses.展开更多
This paper presents a novel working mechanism of a micropump using micropaddles(MPs)to actively manipulate fluid based on 3 D printing technology.The novel working principle is systematically discussed using analysis,...This paper presents a novel working mechanism of a micropump using micropaddles(MPs)to actively manipulate fluid based on 3 D printing technology.The novel working principle is systematically discussed using analysis,computation and experiment methods.A theoretical model is established to research the working mechanism and crucial parameters for driving ability,such as MPs shape,size,vibration amplitude and frequency.Two different 3 D printing techniques that simplify the multi-step process into only one step are introduced to manufacture the prototype pump for investigating the principle experimentally.A testing system is designed to evaluate the flow rate of pumps with eight different vibrating paddles.A maximum flux of 127.9 mL/min is obtained at an applied voltage of 9 V.These experiments show that the active-type mechanical pump could not only freely control flow direction but also change flux by adopting different shapes or distribution ways.The advantage of the novel micropump is the application of the MP structure into the micropump system to actively manipulate fluid with flexibility and high driving ability at fairly low power.展开更多
Piezoelectric transducers of different external diameters are designed and fabricated and incorporated into micropumps. Through finite element analysis, it is shown that the volume efficiency of the micropump reaches ...Piezoelectric transducers of different external diameters are designed and fabricated and incorporated into micropumps. Through finite element analysis, it is shown that the volume efficiency of the micropump reaches its maximum value for the first mode of vibration. The variation of maximum displacement with frequency is determined under free and forced vibration. Results demonstrate that this variation shows the same trend for different driving waves at the same driving voltage. The maximum displacement under forced vibration is less than that under free vibration. The displacement increases with decreasing distance from the center of the transducer. The maximum displacement is inversely proportional to the diameter of the transducer and proportional to the driving voltage under both free and forced vibrations. Finally, the micropump flow rate and pressure are measured and are found to manifest the same trend as the maximum displacement under the same driving conditions. For a piezoelectric transducer of 12 mm external diameter, the maximum flow rate and pressure value are 150 μL/min and 346 Pa, respectively, under sine-wave driving at 100 Vpp driving voltage.展开更多
The aim of this paper is to investigate the dynamic characteristics of a valve-less micropump. A dynamic mathe- matical model of the micropump based on a hydraulic analogue system and a simulation method using AMESim ...The aim of this paper is to investigate the dynamic characteristics of a valve-less micropump. A dynamic mathe- matical model of the micropump based on a hydraulic analogue system and a simulation method using AMESim software are developed. By using the finite-element analysis method, the static analysis of the diaphragm is carried out to ob- tain the maximum deflection and volumetric displacement. Dynamic characteristics of the valve-less micropump under different excitation voltages and frequencies are simulated and tested. Because of the discrepancy between simulation results and experimental data at frequencies other than the natural frequency, the revised model for the diaphragm maximum volumetric displacement is presented. Comparison between the simulation results based on the revised model and experimental data shows that the dynamic mathematical model based on the hydraulic analogue system is capable of predicting dynamic characteristics of the valve-less micropump at any excitation voltage and frequency.展开更多
The fabrication and characterization of a hybrid Silicon-PDMS micropump based on MEMS technology is presented. The micropump consists of one chamber,two passive valves and one PDMS diaphragm.A PZT bimorph working as t...The fabrication and characterization of a hybrid Silicon-PDMS micropump based on MEMS technology is presented. The micropump consists of one chamber,two passive valves and one PDMS diaphragm.A PZT bimorph working as the actuator is mounted on the PDMS diaphragm.The use of the PDMS diaphragm and the PZT bimorph can give rise to large displacements of the pump diaphragm,making the micropump more efficient and easier to be fabricated.The flow rate of the micropump is a function to the voltage and frequency of the applied square wave.When a square wave of 100V is applied,a maximum flow rate of 317μL/min and a back-pressure of 2 kPa are achieved at 20 Hz.展开更多
A parallel dynamic passive valveless micropump was designed, which consists of three layers-valve, diaphragm and electromagnetic coil. The valve was wetly etched in a silicon wafer, the diaphragm was a PDMS （polydime...A parallel dynamic passive valveless micropump was designed, which consists of three layers-valve, diaphragm and electromagnetic coil. The valve was wetly etched in a silicon wafer, the diaphragm was a PDMS （polydimethyl siloxane） film spun on a silicon wafer with embedded permanent magnet posts, and the coil was electroplated on a silicon substrate. Under the actuation of the magnetic field generated by coils, the flexible diaphragm could be displaced upwards and downwards. After analyzing magnetic and mechanical characteristic of the flexible membrane and direction-dependence of the nozzle, a micropump was designed. And the relative length （L/d） of the micropump nozzle was taken 4. A 7 × 7 array of permanent magnetic posts was embedded in the PDMS film. Two diaphragms worked in an anti-step mode, which could relieve the liquid shock and increase the discharge of the micropump. The ANSYS and Matlab were adopted to analyze the actuation effect of the coil and the flow characteristic of the micropump. Results show that when actuated under a 0.3 A, 100 Hz current, the displacement of the diaphragm is more than 30 μm, and the discharge of the micropump is about 6 μL/s.展开更多
A novel viscous micropump consisting of a cylindrical rotor eccentrically placed inside a microchannel is simulated by the two Volume-CAD(V-CAD)framework-based flow solvers,i.e.,the direct simulation Monte Carlo(DSMC)...A novel viscous micropump consisting of a cylindrical rotor eccentrically placed inside a microchannel is simulated by the two Volume-CAD(V-CAD)framework-based flow solvers,i.e.,the direct simulation Monte Carlo(DSMC)package(named as V-DSMC)and the Navier-Stoke solver(named as V-Flow).V-DSMC is used in the case of the pump applied to gas,while V-Flow is applied to model the pump in the case of liquid working medium.The pumping performance curves under different liquid media with the variation of Reynolds number,as well as under different eccentricity factors are obtained.The performance and the flow filed characteristics are very sensitive to the tangential momentum accommodation coefficient in the case of gas medium.Three recirculations exist in the flow field,and the sizes of recirculation are different at the different operating points in a performance curve.展开更多
This paper presents the optimization of 3D valveless diaphragm micropump for medical applications.The pump comprises an inlet and outlet diffuser connected to the main chamber equipped with a periodically moving diaph...This paper presents the optimization of 3D valveless diaphragm micropump for medical applications.The pump comprises an inlet and outlet diffuser connected to the main chamber equipped with a periodically moving diaphragm that generates the unsteady flow within the device.The optimization,which is related exclusively to the diaphragm motion,aims at maximizing the net flowrate and minimizing the backflow at the outlet diffuser.All CFD analyses are performed using an in-house cut-cell method,based on the finite volume approach,on a many-processor system.To reduce the optimization turn-around time,two optimization methods,a gradient-free evolutionary algorithm enhanced by surrogate evaluation models and a gradient-based(GB)method are synergistically used.To support the GB optimization,the continuous adjoint method that computes the gradient of the objectives with respect to the design variables has been developed and programmed.Using the hybrid optimization method,the Pareto front of non-dominated solutions,in the two-objective space,is computed.Finally,a couple of optimal solutions selected from the computed Pareto front are re-evaluated by considering uncertainties in the operating conditions;these are quantified using the polynomial chaos expansion method.展开更多
The concept and structure of serial-connection multi-chamber (SCMC) micropumps with cantilever valves is introduced. The SCMC micropump, which can be manufactured using conventional production techniques and materials...The concept and structure of serial-connection multi-chamber (SCMC) micropumps with cantilever valves is introduced. The SCMC micropump, which can be manufactured using conventional production techniques and materials, has a multi-layer circular planar structure. The border-upon piezoelectric actuators of a SCMC micropump work in anti-phase, as a result the pumping performance is similar to that of several single-chamber pumps running in series. The theoretical analysis shows that the pumping performance of a SCMC micropump depends not only on the characteristic and geometrical parameters of the piezoelectric actuators, but also on the number of pump chambers. Both flowrate and pressure of a SCMC pump can be enhanced to a certain extent. Four piezoelectric micropumps with different chambers were fabricated and tested. The testing results show that the enhancing extents of the flowrate and pressure of a SCMC piezoelectric micropump are different. The maximum flowrate and pressure of the four-chamber pump achieved are 2.5 times and 3.6 times those of the single-chamber pump achieved.展开更多
PZT-based valveless micropump is a microactuator that can be used for controlling and delivering tiny amounts of fluids,and diffuser/nozzle plays an important role when this type of micropump drives the fluid flowing ...PZT-based valveless micropump is a microactuator that can be used for controlling and delivering tiny amounts of fluids,and diffuser/nozzle plays an important role when this type of micropump drives the fluid flowing along a specific direction.In this paper,a numerical model of micropump has been proposed,and the fluidic properties of diffuser/nozzle have been simulated with ANSYS.With the method of finite-element analysis,the increased pressure drop between inlet and outlet of diffuser/nozzle induces the increment of flow rate in both diffuser and nozzle simultaneously,but the increasing rate of diffuser is faster than that of nozzle.The L/R,ratio of L(length of cone pipe) and R(radius of minimal cross section of cone pipe) plays an important role in fluidic performance of diffuser and nozzle as well,and the mean flow rate will decrease with increment of L/R.The mean flow rate reaches its peak value when L/R with the value of 10 regardless the divergence angle of diffuser or nozzle.The simulation results indicate that the fluidic properties of diffuser/nozzle can be defined by its geometric structure,and accordingly determine the efficiency of micropump.展开更多
Transdermal drug delivery(TDD)system based on piezoelectric micropumps is a novel route of drug delivery that is wearable and highly patient-compliant.The advantage of valveless micropumps,such as their simple structu...Transdermal drug delivery(TDD)system based on piezoelectric micropumps is a novel route of drug delivery that is wearable and highly patient-compliant.The advantage of valveless micropumps,such as their simple structure,high reliability and low cost,have been investigated in comparison to valve-based micropumps.However,the flow pulsation and backflow effect of valveless pump can reduce the controllability and precision of the system.Here,a TDD wearable device integrated with a dual-pump parallel valveless piezoelectric micropump and hollow microneedle array is presented,which is fabricated by means of 3D printing technology.The simulation analysis and experimental results indicate that the dual-pump parallel micropump with asynchronous driving can achieve a full forward flow and reduces the influence of flow pulsation on the system’s stability,showing the excellent controllability and high precision of the device.The output flow rate and pressure of the micropump can be controlled by the driving signal,which are about 1.61 mL/min and 700 Pa with the sine driving signal of 40 V,600 Hz.Through animal experiments,we demonstrate that the device can successfully deliver insulin to mice and control blood glucose.In conclusion,this TDD device which potentially provides low-cost and high-precision results than existing technologies,shows considerable promise in wearable drug delivery applications,especially in managing chronic diseases that require long-term treatment.展开更多
Acoustofluidics is a term describing the class of phenomena in which mechanical or acoustic vibrations induce a deformation or a flow in a fluid.Many deficiencies in our understanding of these phenomena remain to be a...Acoustofluidics is a term describing the class of phenomena in which mechanical or acoustic vibrations induce a deformation or a flow in a fluid.Many deficiencies in our understanding of these phenomena remain to be addressed,with respect to the fundamental theoretical framework as well as in numerous applications.In this regard,the frequency of external forcing is a key parameter.Owing to the low cost,substantial magnitude,and versatility associated with acoustofluidic phenomena at audible frequencies,studies of these phenomena in the audible range have emerged with increasing amount in recent years and have attracted considerable attention.However,compared with studies focusing on the ultrasonic frequency domain,critical features and information specific to audible acoustofluidics remain dispersed across many independent publications,and a systematic integration of the literature on this topic is necessary.Accordingly,this review summarizes the basic theory and methods for generating vibrations in the audible range,presents various applications thereof in biology,chemistry,and other fields,and provides a high-level overview of the current status of the topic to motivate developing interesting proposals for further research in this field of study.展开更多
This paper presented a novel electrohydrodynamic (EHD) micropump based on MEMS technology. The working mechanisms and classification of EHD micropump were introduced. The fabrication process of EHD micropump was prese...This paper presented a novel electrohydrodynamic (EHD) micropump based on MEMS technology. The working mechanisms and classification of EHD micropump were introduced. The fabrication process of EHD micropump was presented with the material selection,optimal design of microelectrode and assembly process. Static pressure experiments and flow experiments were carried out using different fluid and the channel depth. The results indicated that the micropump could achieve a maximum static pressure head of 268 Pa at an applied voltage of 90 V. The maximum flow rate of the micropump-driven fluid could reach 106 μL/min. This paper analyzed the future of combining micropump with heat pipe to deal with heat dissipation of high power electronic chips. The maximum heat dissipation capacity of 87 W/cm2 can be realized by vaporizing the micropump-driven liquid on vaporizing section of the heat pipe.展开更多
The micropump is the heart of microfluidics systems.However,for mechanical micropumps,bearing wear failure has been a major obstacle to performance and reliability.Hydrodynamic suspension,which can make the rotating c...The micropump is the heart of microfluidics systems.However,for mechanical micropumps,bearing wear failure has been a major obstacle to performance and reliability.Hydrodynamic suspension,which can make the rotating components levitate in liquid without any mechanical friction,is applied to break this bottleneck.In this paper,a novel kind of hydrodynamic suspension micropump(HSMP) without a grooved thrust bearing is proposed.Based on the centrifugal effect,the HSMP uses a rotating rotor to accelerate and pressurize adjacent fluid,and thus reacting forces are generated on the rotor surfaces to levitate it.The mechanisms of suspension forces formation,the centrifugal effect and the wedge effect in the liquid films near the rotor are identified using theoretical analysis and simulation.The variation in suspension forces with rotor position is investigated,revealing that the suspension bearings of the HSMP,similar to a spring damper,can self-adjust suspension forces along with a change in rotor position.Moreover,the suspension stiffness is positively correlated with the rotating speed.The HSMP prototype designed herein,whose overall size is only 34 mm × 34 mm × 31 mm,can provide a maximum output performance of3230 mL/min and 96.3 kPa at 20000 r/min,which is manyfold greater than other micropumps.The proposed HSMP is demonstrated to be more powerful with a simple structure,high power density,and high reliability.展开更多
文摘This paper presents the design, fabrication, and experimental characterization of a peristaltic micropump. The micropump is composed of two layers fabricated from Polydimethylsiloxane （PDMS） material. The first layer has a rectangular channel and two valve seals. Three rectangular mini lightweight piezo-composite actuators are integrated in the second layer, and used as actuation parts. Two layers are bonded, and covered by two Polymethyl Methacrylate （PMMA） plates, which help increase the stiffness of the micropump. A maximum flow rate of 900μL.min 1 and a maximum backpressure of 1.8 kPa are recorded when water is used as pump liquid. We measured the power consumption of the micropump. The micropump is found to be a promising candidate for bio-medical application due to its bio-compatibility, portability, bidirectionality, and simple effective design.
基金Project supported by the National Natural Science Foundation of China (No. 10472036).
文摘This paper employs the integral-averaged method of thickness to approximate the periodical flows in a piezoelectric micropump, with a shallow water equation including nonlinearity and viscous damp presented to characterize the flows in micropump. The finite element method is used to obtain a matrix equation of fluid pressure. The fluid pressure equation is combined with the vibration equation of a silicon diaphragm to construct a liquid-solid coupled equation for reflecting the interaction between solid diaphragm and fluid motion in a micropump. Numerical results of a mode analysis of the coupled system indicate that the natural frequencies of the coupled system are much lower than those of the non-coupled system. The influence of additional mass and viscous damp of fluid on the natural frequencies of the coupled system is more significant as the pump thickness is small. It is found that the vibration shape functions of silicon diaphragm of the coupled system are almost the same as those of the non-coupled system. This paper also gives the first-order amplitude-frequency relationship of the silicon diaphragm, which is necessary for the flow-rate-frequency analysis of a micropump.
基金the financial support from the National Science Foundation of China(Grant No.20299030,60427001 and 60501020).
文摘According to the'elastic buffer mechanism'and the'variable gap mechanism',a new device,which is both micropump and active microvalve actuated by PZT bimorph cantilever,was fabricated with polydimethyisiloxane (PDMS) and silicon chip.The thickness of the micropump membrance is about 180μm.The diameter and the depth of micropump chamber cavity are 6 mm and 40μm,respectively.The performances of the micropump,such as pump rate and backpressure,were characterized.As a flow-rectifying element,the diffusers and active valve were used instead of passive check valves.The flow rate and the backpressure of the micropump are about 420μL/min and 2 kPa when applying a 100 V square wave driving voltage at frequency of 35 Hz.
文摘In this paper,we propose a new prototype model of a micro pump using ICPF(Ionic Conducting Polymer Film)actuator as the servo actuator.This micro pump consists of two active one- way valves that make use of the same ICPF actuator.The overall size of this micro pump prototype is 12mm in diameter and 20mm in length.The actuating mechanism is as follows:(1)The ICPF actuator as the diaphragm is bent into anode side by application of electricity.Then the volume of the pump chamber increases,resulting in the inflow of liquid from the inlet to the chamber.(2)By changing the current direction,the volume of the pump chamber decreases,resulting in the liquid flow from the chamber to the outlet.(3)The ICPF actuator is put on a sine voltage,the micro pump provides liquid flow from the inlet to the outlet continuously.Characteristic of the micro pump is measured.The experimental results indicate that the micro pump has the satisfactory responses.
基金financial support from the Science and Technology Commission of Shanghai Municipality(STCSM,No.17DZ2291400 and No.17DZ2203100)
文摘This paper presents a novel working mechanism of a micropump using micropaddles(MPs)to actively manipulate fluid based on 3 D printing technology.The novel working principle is systematically discussed using analysis,computation and experiment methods.A theoretical model is established to research the working mechanism and crucial parameters for driving ability,such as MPs shape,size,vibration amplitude and frequency.Two different 3 D printing techniques that simplify the multi-step process into only one step are introduced to manufacture the prototype pump for investigating the principle experimentally.A testing system is designed to evaluate the flow rate of pumps with eight different vibrating paddles.A maximum flux of 127.9 mL/min is obtained at an applied voltage of 9 V.These experiments show that the active-type mechanical pump could not only freely control flow direction but also change flux by adopting different shapes or distribution ways.The advantage of the novel micropump is the application of the MP structure into the micropump system to actively manipulate fluid with flexibility and high driving ability at fairly low power.
基金funded by the National Natural Science Foundation of China(Grant No.51505128)supported by the Henan Key Technology Research and Development Program(Grant No.182102410061)
文摘Piezoelectric transducers of different external diameters are designed and fabricated and incorporated into micropumps. Through finite element analysis, it is shown that the volume efficiency of the micropump reaches its maximum value for the first mode of vibration. The variation of maximum displacement with frequency is determined under free and forced vibration. Results demonstrate that this variation shows the same trend for different driving waves at the same driving voltage. The maximum displacement under forced vibration is less than that under free vibration. The displacement increases with decreasing distance from the center of the transducer. The maximum displacement is inversely proportional to the diameter of the transducer and proportional to the driving voltage under both free and forced vibrations. Finally, the micropump flow rate and pressure are measured and are found to manifest the same trend as the maximum displacement under the same driving conditions. For a piezoelectric transducer of 12 mm external diameter, the maximum flow rate and pressure value are 150 μL/min and 346 Pa, respectively, under sine-wave driving at 100 Vpp driving voltage.
基金Project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education of China (Grant No. 24403604)the Fundamental Research Funds for the Central Universities, China (Grant No. ZYGX2011J083)
文摘The aim of this paper is to investigate the dynamic characteristics of a valve-less micropump. A dynamic mathe- matical model of the micropump based on a hydraulic analogue system and a simulation method using AMESim software are developed. By using the finite-element analysis method, the static analysis of the diaphragm is carried out to ob- tain the maximum deflection and volumetric displacement. Dynamic characteristics of the valve-less micropump under different excitation voltages and frequencies are simulated and tested. Because of the discrepancy between simulation results and experimental data at frequencies other than the natural frequency, the revised model for the diaphragm maximum volumetric displacement is presented. Comparison between the simulation results based on the revised model and experimental data shows that the dynamic mathematical model based on the hydraulic analogue system is capable of predicting dynamic characteristics of the valve-less micropump at any excitation voltage and frequency.
基金The authors greatly acknowledge the financial support from the National Science Foundation of China （Grant number 20299030, 60427001 and 60501020）.
文摘The fabrication and characterization of a hybrid Silicon-PDMS micropump based on MEMS technology is presented. The micropump consists of one chamber,two passive valves and one PDMS diaphragm.A PZT bimorph working as the actuator is mounted on the PDMS diaphragm.The use of the PDMS diaphragm and the PZT bimorph can give rise to large displacements of the pump diaphragm,making the micropump more efficient and easier to be fabricated.The flow rate of the micropump is a function to the voltage and frequency of the applied square wave.When a square wave of 100V is applied,a maximum flow rate of 317μL/min and a back-pressure of 2 kPa are achieved at 20 Hz.
文摘A parallel dynamic passive valveless micropump was designed, which consists of three layers-valve, diaphragm and electromagnetic coil. The valve was wetly etched in a silicon wafer, the diaphragm was a PDMS （polydimethyl siloxane） film spun on a silicon wafer with embedded permanent magnet posts, and the coil was electroplated on a silicon substrate. Under the actuation of the magnetic field generated by coils, the flexible diaphragm could be displaced upwards and downwards. After analyzing magnetic and mechanical characteristic of the flexible membrane and direction-dependence of the nozzle, a micropump was designed. And the relative length （L/d） of the micropump nozzle was taken 4. A 7 × 7 array of permanent magnetic posts was embedded in the PDMS film. Two diaphragms worked in an anti-step mode, which could relieve the liquid shock and increase the discharge of the micropump. The ANSYS and Matlab were adopted to analyze the actuation effect of the coil and the flow characteristic of the micropump. Results show that when actuated under a 0.3 A, 100 Hz current, the displacement of the diaphragm is more than 30 μm, and the discharge of the micropump is about 6 μL/s.
文摘A novel viscous micropump consisting of a cylindrical rotor eccentrically placed inside a microchannel is simulated by the two Volume-CAD(V-CAD)framework-based flow solvers,i.e.,the direct simulation Monte Carlo(DSMC)package(named as V-DSMC)and the Navier-Stoke solver(named as V-Flow).V-DSMC is used in the case of the pump applied to gas,while V-Flow is applied to model the pump in the case of liquid working medium.The pumping performance curves under different liquid media with the variation of Reynolds number,as well as under different eccentricity factors are obtained.The performance and the flow filed characteristics are very sensitive to the tangential momentum accommodation coefficient in the case of gas medium.Three recirculations exist in the flow field,and the sizes of recirculation are different at the different operating points in a performance curve.
文摘This paper presents the optimization of 3D valveless diaphragm micropump for medical applications.The pump comprises an inlet and outlet diffuser connected to the main chamber equipped with a periodically moving diaphragm that generates the unsteady flow within the device.The optimization,which is related exclusively to the diaphragm motion,aims at maximizing the net flowrate and minimizing the backflow at the outlet diffuser.All CFD analyses are performed using an in-house cut-cell method,based on the finite volume approach,on a many-processor system.To reduce the optimization turn-around time,two optimization methods,a gradient-free evolutionary algorithm enhanced by surrogate evaluation models and a gradient-based(GB)method are synergistically used.To support the GB optimization,the continuous adjoint method that computes the gradient of the objectives with respect to the design variables has been developed and programmed.Using the hybrid optimization method,the Pareto front of non-dominated solutions,in the two-objective space,is computed.Finally,a couple of optimal solutions selected from the computed Pareto front are re-evaluated by considering uncertainties in the operating conditions;these are quantified using the polynomial chaos expansion method.
文摘The concept and structure of serial-connection multi-chamber (SCMC) micropumps with cantilever valves is introduced. The SCMC micropump, which can be manufactured using conventional production techniques and materials, has a multi-layer circular planar structure. The border-upon piezoelectric actuators of a SCMC micropump work in anti-phase, as a result the pumping performance is similar to that of several single-chamber pumps running in series. The theoretical analysis shows that the pumping performance of a SCMC micropump depends not only on the characteristic and geometrical parameters of the piezoelectric actuators, but also on the number of pump chambers. Both flowrate and pressure of a SCMC pump can be enhanced to a certain extent. Four piezoelectric micropumps with different chambers were fabricated and tested. The testing results show that the enhancing extents of the flowrate and pressure of a SCMC piezoelectric micropump are different. The maximum flowrate and pressure of the four-chamber pump achieved are 2.5 times and 3.6 times those of the single-chamber pump achieved.
基金Supported by′111′Project and Chongqing Natural Science Foundation(2006BB2043,2006BB2142)
文摘PZT-based valveless micropump is a microactuator that can be used for controlling and delivering tiny amounts of fluids,and diffuser/nozzle plays an important role when this type of micropump drives the fluid flowing along a specific direction.In this paper,a numerical model of micropump has been proposed,and the fluidic properties of diffuser/nozzle have been simulated with ANSYS.With the method of finite-element analysis,the increased pressure drop between inlet and outlet of diffuser/nozzle induces the increment of flow rate in both diffuser and nozzle simultaneously,but the increasing rate of diffuser is faster than that of nozzle.The L/R,ratio of L(length of cone pipe) and R(radius of minimal cross section of cone pipe) plays an important role in fluidic performance of diffuser and nozzle as well,and the mean flow rate will decrease with increment of L/R.The mean flow rate reaches its peak value when L/R with the value of 10 regardless the divergence angle of diffuser or nozzle.The simulation results indicate that the fluidic properties of diffuser/nozzle can be defined by its geometric structure,and accordingly determine the efficiency of micropump.
基金supported by the National Natural Science Foundation of China(52305608)the Medical Innovation Research Program of Shanghai Science and Technology Innovation Action Plan(24DX2800100)+2 种基金Key Technologies Research and Development Program(2022YFB3603100)School of Microelectronics,Shanghai University—Intelligent sensing Chip Technology Collaborative Innovation CenterKey Laboratory of Advanced Display and System Applications Ministry of Education Supporting Key Scientific Research Bases.
文摘Transdermal drug delivery(TDD)system based on piezoelectric micropumps is a novel route of drug delivery that is wearable and highly patient-compliant.The advantage of valveless micropumps,such as their simple structure,high reliability and low cost,have been investigated in comparison to valve-based micropumps.However,the flow pulsation and backflow effect of valveless pump can reduce the controllability and precision of the system.Here,a TDD wearable device integrated with a dual-pump parallel valveless piezoelectric micropump and hollow microneedle array is presented,which is fabricated by means of 3D printing technology.The simulation analysis and experimental results indicate that the dual-pump parallel micropump with asynchronous driving can achieve a full forward flow and reduces the influence of flow pulsation on the system’s stability,showing the excellent controllability and high precision of the device.The output flow rate and pressure of the micropump can be controlled by the driving signal,which are about 1.61 mL/min and 700 Pa with the sine driving signal of 40 V,600 Hz.Through animal experiments,we demonstrate that the device can successfully deliver insulin to mice and control blood glucose.In conclusion,this TDD device which potentially provides low-cost and high-precision results than existing technologies,shows considerable promise in wearable drug delivery applications,especially in managing chronic diseases that require long-term treatment.
基金financially supported by the National Key Research and Development Program of China(2022YFC2406600 and 2020YFB2009000)the Program for Innovation Team of Shaanxi Province(2021TD-23)。
文摘Acoustofluidics is a term describing the class of phenomena in which mechanical or acoustic vibrations induce a deformation or a flow in a fluid.Many deficiencies in our understanding of these phenomena remain to be addressed,with respect to the fundamental theoretical framework as well as in numerous applications.In this regard,the frequency of external forcing is a key parameter.Owing to the low cost,substantial magnitude,and versatility associated with acoustofluidic phenomena at audible frequencies,studies of these phenomena in the audible range have emerged with increasing amount in recent years and have attracted considerable attention.However,compared with studies focusing on the ultrasonic frequency domain,critical features and information specific to audible acoustofluidics remain dispersed across many independent publications,and a systematic integration of the literature on this topic is necessary.Accordingly,this review summarizes the basic theory and methods for generating vibrations in the audible range,presents various applications thereof in biology,chemistry,and other fields,and provides a high-level overview of the current status of the topic to motivate developing interesting proposals for further research in this field of study.
基金supported by the National Natural Science Foundation of China(Grant No.50676001)
文摘This paper presented a novel electrohydrodynamic (EHD) micropump based on MEMS technology. The working mechanisms and classification of EHD micropump were introduced. The fabrication process of EHD micropump was presented with the material selection,optimal design of microelectrode and assembly process. Static pressure experiments and flow experiments were carried out using different fluid and the channel depth. The results indicated that the micropump could achieve a maximum static pressure head of 268 Pa at an applied voltage of 90 V. The maximum flow rate of the micropump-driven fluid could reach 106 μL/min. This paper analyzed the future of combining micropump with heat pipe to deal with heat dissipation of high power electronic chips. The maximum heat dissipation capacity of 87 W/cm2 can be realized by vaporizing the micropump-driven liquid on vaporizing section of the heat pipe.
基金supported by the Open Fund of Science and Technology on Thermal Energy and Power Laboratory (Grant No.TPL2019B03)。
文摘The micropump is the heart of microfluidics systems.However,for mechanical micropumps,bearing wear failure has been a major obstacle to performance and reliability.Hydrodynamic suspension,which can make the rotating components levitate in liquid without any mechanical friction,is applied to break this bottleneck.In this paper,a novel kind of hydrodynamic suspension micropump(HSMP) without a grooved thrust bearing is proposed.Based on the centrifugal effect,the HSMP uses a rotating rotor to accelerate and pressurize adjacent fluid,and thus reacting forces are generated on the rotor surfaces to levitate it.The mechanisms of suspension forces formation,the centrifugal effect and the wedge effect in the liquid films near the rotor are identified using theoretical analysis and simulation.The variation in suspension forces with rotor position is investigated,revealing that the suspension bearings of the HSMP,similar to a spring damper,can self-adjust suspension forces along with a change in rotor position.Moreover,the suspension stiffness is positively correlated with the rotating speed.The HSMP prototype designed herein,whose overall size is only 34 mm × 34 mm × 31 mm,can provide a maximum output performance of3230 mL/min and 96.3 kPa at 20000 r/min,which is manyfold greater than other micropumps.The proposed HSMP is demonstrated to be more powerful with a simple structure,high power density,and high reliability.
