The operational stability of radial journal bearings is the bottleneck that limits the reliability of hydraulic suspension micropump. Due to self-excited vibrations, the whirl amplitude of the plain journal bearing(PJ...The operational stability of radial journal bearings is the bottleneck that limits the reliability of hydraulic suspension micropump. Due to self-excited vibrations, the whirl amplitude of the plain journal bearing(PJB) is large at high rotational speeds,which will accelerate wear failure. It has been proven that employing herringbone grooved journal bearing(HGJB) is an effective method to reduce the whirl amplitude and improve operational stability. However, enhancing the stability of journal bearings in micro-pumps by herringbone grooved structures has rarely been studied, and its effect needs to be verified. We validated the mechanism of the stability improvement with the CFD method and compared the dynamic characteristics of HGJB and PJB by rotor dynamics evaluation and experiment. The experimental results show that under the same conditions the whirl amplitude of the HGJB decreases by 29.61% in the x direction and by 24.09% in the y direction compared with that of the PJB. This study reveals the effect of the herringbone grooved structure on the operational stability of bearings and may provide guidance for the reliability improvement of hydraulic suspension micro-pump.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
基金supported by the Open Fund of Science and Technology on Thermal Energy and Power Laboratory(Grant No. TPL 2019B03)。
文摘The operational stability of radial journal bearings is the bottleneck that limits the reliability of hydraulic suspension micropump. Due to self-excited vibrations, the whirl amplitude of the plain journal bearing(PJB) is large at high rotational speeds,which will accelerate wear failure. It has been proven that employing herringbone grooved journal bearing(HGJB) is an effective method to reduce the whirl amplitude and improve operational stability. However, enhancing the stability of journal bearings in micro-pumps by herringbone grooved structures has rarely been studied, and its effect needs to be verified. We validated the mechanism of the stability improvement with the CFD method and compared the dynamic characteristics of HGJB and PJB by rotor dynamics evaluation and experiment. The experimental results show that under the same conditions the whirl amplitude of the HGJB decreases by 29.61% in the x direction and by 24.09% in the y direction compared with that of the PJB. This study reveals the effect of the herringbone grooved structure on the operational stability of bearings and may provide guidance for the reliability improvement of hydraulic suspension micro-pump.
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.
