The piezoelectric pump with nozzle/diffuser-elements, which oscillating formdiffering from regular volumetric reciprocating or rotating pumps because there arenozzle/diffuser-elements substituted for regular valves, i...The piezoelectric pump with nozzle/diffuser-elements, which oscillating formdiffering from regular volumetric reciprocating or rotating pumps because there arenozzle/diffuser-elements substituted for regular valves, is a new type pump whose actuator is apiezoelectric ceramal part with verse piezoelectric effect In recent year, piezoelectric pump ispaid increasing attention to because it is an ideal candidate in application in such area as medicalhealth, mechanical tools and micro-mechanism. The fundamental research on it, however, is still notmade through. Focuses on the phenomenon of different directions of flow among Germany pump, Chinesepump and Swiss pump, which are all fitted with nozzle/diffuser-elements, and analyzes the coneangle of nozzle/diffuser-elements based on the flow equation of valve-less piezoelectric pump withnozzle/diffuser-elements. As a result, the concepts of diffuser toss coefficient and losscoefficient are introduced to explain these phenomena, from which a discussion is given on theoptimization of the cone angle of nozzle/diffuser-element aiming at the maximum of pump flow.展开更多
Intenal combustion pump （ICP） is a new type power device turning the thermal energy from fuel combustion into fluid pressure energy. Three cylinders prototype has just been developed. The study on the influence of v...Intenal combustion pump （ICP） is a new type power device turning the thermal energy from fuel combustion into fluid pressure energy. Three cylinders prototype has just been developed. The study on the influence of valve＇s characteristic on ICP＇s total performance will found the base for its optimum design. Based on the theoretical and testing fruits of single cylinder prototype, the performance of the valves and complete appliance of the latest is simulated. When the natural frequency of valves is approximately to the round number times of the working frequency, volumetric efficiency is seriously low. The nominal rotational speed of the prototype is nearly to the speed where the volumetric efficiency is lowest, which is harmful to the normal work of ICP, so further structure optimization of valves should be carried out. The change of volumetric efficiency has great influence on the fuel consumption rate, output flow, effective thermal efficiency, effective power, and so on, but little on output pressure.展开更多
The optimization of the valve plate transition region is an important way of reducing the noise emission for an axial piston pump. However, the optimized methods through simulation or experiment are actually trial and...The optimization of the valve plate transition region is an important way of reducing the noise emission for an axial piston pump. However, the optimized methods through simulation or experiment are actually trial and error, and they cannot indicate the precise structural parameters of the valve plate transition region. In this study, a new design method for the transition region of valve plate based on the matching of flow area and reduction of transient reverse flow was proposed, and with which a valve plate was designed. Then, the impact of the flow ripple in the discharge line of an axial piston pump and the pressure overshoot and undershoot in the piston chamber on hydraulic and structural noise for axial piston pump is discussed. The noise reduction effect of the axial piston pump with this valve plate was analyzed by adopting a flow characteristic simulation model. Finally, the results showed that the application of this design method could contribute much to the reduction of the flow ripple and elimination of the pressure overshoot and undershoot. As a consequence, the method can be used in the design of a low-noise open circuit axial piston pump.展开更多
基金This project is supported by Municipal Natural Science Foundation of Beiiing , China (No.3032005).
文摘The piezoelectric pump with nozzle/diffuser-elements, which oscillating formdiffering from regular volumetric reciprocating or rotating pumps because there arenozzle/diffuser-elements substituted for regular valves, is a new type pump whose actuator is apiezoelectric ceramal part with verse piezoelectric effect In recent year, piezoelectric pump ispaid increasing attention to because it is an ideal candidate in application in such area as medicalhealth, mechanical tools and micro-mechanism. The fundamental research on it, however, is still notmade through. Focuses on the phenomenon of different directions of flow among Germany pump, Chinesepump and Swiss pump, which are all fitted with nozzle/diffuser-elements, and analyzes the coneangle of nozzle/diffuser-elements based on the flow equation of valve-less piezoelectric pump withnozzle/diffuser-elements. As a result, the concepts of diffuser toss coefficient and losscoefficient are introduced to explain these phenomena, from which a discussion is given on theoptimization of the cone angle of nozzle/diffuser-element aiming at the maximum of pump flow.
基金supported by National Natural Science Foundation of China (Grant No. 50575107)
文摘Intenal combustion pump （ICP） is a new type power device turning the thermal energy from fuel combustion into fluid pressure energy. Three cylinders prototype has just been developed. The study on the influence of valve＇s characteristic on ICP＇s total performance will found the base for its optimum design. Based on the theoretical and testing fruits of single cylinder prototype, the performance of the valves and complete appliance of the latest is simulated. When the natural frequency of valves is approximately to the round number times of the working frequency, volumetric efficiency is seriously low. The nominal rotational speed of the prototype is nearly to the speed where the volumetric efficiency is lowest, which is harmful to the normal work of ICP, so further structure optimization of valves should be carried out. The change of volumetric efficiency has great influence on the fuel consumption rate, output flow, effective thermal efficiency, effective power, and so on, but little on output pressure.
基金the National Basic Research Program (973 Program) of China，the Science Fund for Creative Research Groups of the National Natural Science Foundation of China
文摘The optimization of the valve plate transition region is an important way of reducing the noise emission for an axial piston pump. However, the optimized methods through simulation or experiment are actually trial and error, and they cannot indicate the precise structural parameters of the valve plate transition region. In this study, a new design method for the transition region of valve plate based on the matching of flow area and reduction of transient reverse flow was proposed, and with which a valve plate was designed. Then, the impact of the flow ripple in the discharge line of an axial piston pump and the pressure overshoot and undershoot in the piston chamber on hydraulic and structural noise for axial piston pump is discussed. The noise reduction effect of the axial piston pump with this valve plate was analyzed by adopting a flow characteristic simulation model. Finally, the results showed that the application of this design method could contribute much to the reduction of the flow ripple and elimination of the pressure overshoot and undershoot. As a consequence, the method can be used in the design of a low-noise open circuit axial piston pump.
