Modeling and theoretical study of relief chamfer method for reducing the flow ripple of a spool valves distribution radial piston pump

Author(s):  
Tong Guo ◽  
Tianliang Lin ◽  
Haoling Ren ◽  
Cheng Miao ◽  
Shengdun Zhao

This paper presents a study of flow ripple reduction method of a spool valves distribution radial piston pump (SVDRPP). Relief chamfers are adopted to prolong and moderate the opening processes of the delivery spool valves, thus to relieve the pressure surges as well as the consequent flow ripples, vibrations and noises. The mathematical model of this method is established and multiple numerical simulations are conducted to analyze the mechanism as well as the effectiveness of this method. According to the simulation results, different relief chamfer angles have varying influences on flow ripple reduction. Remarkable reduction of flow fluctuation from 43.4% to 36% could be achieved, when the relief chamfer angle is set around 30°. Comparisons between the relief chamfer method and the time delay method indicate that the former has better compatibility to the load pressure lower than the rated value; while the latter has better compatibility to the higher load pressure.

Author(s):  
Tong Guo ◽  
Shengdun Zhao ◽  
Chen Liu

This paper studies the flow characteristics and flow ripple reduction techniques of a spool valves distributed radial piston pump. The mathematical models of the pump are established, and simulations based on the mathematics are performed in AMESim environment. The results indicate that the spool valves distributed radial piston pump has fewer flow fluctuations than the pump distributed by check valves, due to the rigid motion of its distribution component—the spool valves. Then, in order to reduce the flow ripple of the spool valves distributed radial piston pump, three techniques, namely, time delay, relief chamfer and transition compression filter volume, are proposed and their working principles are illustrated. Particularly, the design method of time delay is elaborated and its effectiveness is evaluated. The simulation results suggest that with the usage of the time delay method, the fluctuation range of the spool valves distributed radial piston pump is expected to be reduced by 21.7%.


2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Fei Lyu ◽  
Shaogan Ye ◽  
Junhui Zhang ◽  
Bing Xu ◽  
Weidi Huang ◽  
...  

Abstract The output flow ripple of the axial piston pump is one of the excitation sources for the hydraulic system vibration. The amplitudes of its specific harmonics must be reduced to avoid the resonance with the hydraulic pipeline. In this paper, a method on the nonuniform distribution of the pistons is put forward to adjust the flow ripple. The deflection angles of the pistons are used to describe the distribution rule. The distribution rule is imported to the Fourier expansion of the flow rate of each single-piston chamber, and then every single flow rate is superposed to obtain the Fourier coefficient of total flow rate that becomes the function of deflection angles. After this, objective optimization design is carried out to reduce the amplitudes of specific harmonics. Finally, the dynamic simulation model of the nonuniformly distributed axial piston pump is established to verify the effects of objective optimization. The results show that the amplitude of the ninth harmonic of the flow ripple can be reduced by about 40%, and the reductions are about 99% for the 18th and 27th harmonic.


Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1664
Author(s):  
Haocen Hong ◽  
Chunxiao Zhao ◽  
Bin Zhang ◽  
Dapeng Bai ◽  
Huayong Yang

The triangular damping groove on the valve plate can effectively reduce the discharge flow ripple of an axial piston pump, which structural parameters will directly affect the pump’s dynamic characteristics. Herein, a multi-parameter data-based structure optimizing method of the triangular damping groove is investigated using numerical models and simulation results. The mathematical models of a nine-piston pump are proposed and developed by MATLAB/Simulink, and the simulation results are verified by experimental results. Then, the effects of width angle and depth angle on discharge flow are analyzed. Based on the analysis of groove parameters, an optimizing index, which considering the time domain characteristics of discharge flow, is proposed. As results show, comparing with the initial specific groove structure, the amplitude of flow ripple is reduced from 14.6% to 9.8% with the optimized structure. The results demonstrate that the outlet flow ripple can be significantly reduced by the optimized structure, and the proposed multi-parameter optimizing method can play a guiding significance in the design of low-ripple axial piston pumps.


2013 ◽  
Vol 26 (6) ◽  
pp. 1259-1266 ◽  
Author(s):  
Bing Xu ◽  
Yuechao Song ◽  
Huayong Yang

Author(s):  
Hamdy Hassan

Abstract In this paper, a theoretical study is presented on enhancement of the solar still performance by using the exhaust gases passing inside a chimney under the still basin. The impact of the exhaust gases temperature on the solar still temperature, productivity, and efficiency are considered. The performance of solar still with chimney is compared with that of conventional solar still. The study is carried out under the hot and climate conditions of Upper Egypt. A complete transient mathematical model of the physical model including the solar still regions temperatures, productivity, and heat transfer between the solar still and the exhaust gases are constructed. The mathematical model is solved numerically by using fourth-order Runge-Kutta method and is programmed by using MATLAB. The mathematical model is validated using an experimental work. The results show that the solar still saline water temperature increases and productivity with using and rising the exhaust gases. Furthermore, the impact of using exhaust gases on the still performance in winter is greater than in summer. using chimney exhaust gases at 75 °C and 125 °C enhances the daily freshwater yield of the conventional still by more than three times and about six times in winter, respectively, and about two and half times and more than three times in summer, respectively.


2021 ◽  
Vol 15 ◽  
pp. 216-221
Author(s):  
Mahmoud Mohamed El-Ghobashy El-Hagar

One of the major problems facing the use of the wind driven reciprocating lift pump is the problem of starting. The required starting torque of the pump is at least three times the average torque. This means that the pump will need a high wind velocity just to be started, after that it will continue to operate at a lower wind velocity because of the lower average torque, provided that there is enough inertia in the system. For this reason, the torque characteristics of the wind turbine – reciprocating pump combination are very important. Thus, there is a real need to develop new methods in order to reduce this starting performance of the reciprocating pump. This paper presents a theoretical study to reduce the starting torque of a non-conventional reciprocating piston pump using new methods, for example, changing the wind machine parameters, such as the aerodynamics configuration of the rotor and blade elements, or by studying the effect of wind speed velocity on the starting torque. Also by changing the cross-section area of the piston or by changing the static head of the piston pump or by controlling the flow rate of the piston pump.


Author(s):  
Gianluca Marinaro ◽  
Emma Frosina ◽  
Kim Stelson ◽  
Adolfo Senatore

Abstract This research presents a lumped parameter numerical model aimed at designing and optimizing an axial piston pump. For the first time, it has been shown that a lumped parameter model can accurately model axial piston pump dynamics based on a comparison with CFD models and experimental results. Since the method is much more efficient than CFD, it can optimize the design. Both steady-state and dynamic behaviors have been analyzed. The model results have been compared with experimental data, showing a good capacity in predicting the pump performance, including pressure ripple. The swashplate dynamics have been investigated experimentally, measuring the dynamic pressure which controls the pump displacement; a comparison with the numerical model results confirmed the high accuracy. An optimization process has been conducted on the valve plate geometry to control fluid-born noise by flow ripple reduction. The NLPQL algorithm is used since it is suitable for this study. The objective function to minimize is the well-known function, the Non-Uniformity Grade, a parameter directly correlated with flow ripple. A prototype of the best design has been realized and tested, confirming a reduction in the pressure ripple. An endurance test was also conducted. As predicted from the numerical model, a significant reduction of cavitation erosion was observed.


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