Research On Operating Characteristics Of Piston Pump In Deepening Environment

The ocean occupied 71% of the surface area and was rich in mineral resources and biological resources,for example,petroleum and natural gas.With deep-sea mining technology became more mature,ocean development gradually moved from shallow sea to deep sea.The operating conditions of operating equipment are very harsh in the deep-sea,which was asked for high technical requirements.The United States,Japan,Russia,Europe and other developed countries or regions have successively developed a number of mature resources exploration and exploitation products.In contrast,Chinese corresponding exploration technology and operational equipment started late and mature products were limited.This paper took the deep-sea piston pump as the research object,analyzed the influence of the change of oil parameters on the control characteristics and efficiency of the piston pump under variable-depth environment,and obtained the variation rule of the working performance of the deep-sea piston pump.Research achievements provided theoretical support for the development of hydraulic equipment and the selection of hydraulic media.The main research contents were as follows:(1)For the problem of the change of hydraulic medium characteristics with the change of water depth,firstly an underwater environment parameter model which set water depth as the independent variable was established,which was used to analyze the variation of environmental parameters under different water depths.In this,the mathematical models of oil viscosity-pressure-temperature characteristics and elastic modulus-pressure-temperature characteristics with environmental parameters as variables were constructed,which analyzed oil characteristics by using the ISO VG 32 hydraulic oil.Getting that the oil viscosity changed in the light of the ?three-stage? change law under water,and the elastic modulus increased in the light of the ?two-stage?.In order to reveal furtherly the mechanism of single environmental parameters,article analyzed the change rule of oil properties by using ambient pressure and seawater temperature as variables.Getting that the reason for the change rules of oil properties was that the environmental parameters varied with the depth of water in a non-linear manner.The relevant provided theoretical support for the analysis of piston pump under water.(2)Based on the oil medium characteristics model,the pressure and flow control model of the deep-sea piston pump were established,which was used to analyze the influence of the internal parameters of the hydraulic system such as the viscosity and elastic modulus on the system performance.When considering the effect of viscosity,the stability of the two control systems increased as the water depth increases,and the response speed and control accuracy decreased.When considering the influence of the elastic modulus,the stability of the two systems decreased as the water depth increases,and the response speed and control accuracy increased.When considering the two parameters of viscosity and elastic modulus at the same time,the stability of the system increased as the depth of water increases,the response speed and control accuracy decreased.By synthesizing the change law of the control characteristics,the conclution was concluded that the control system can be regarded as the variable viscosity-dynamic elastic modulus control system and the variable viscosity-definite elastic modulus control system between 0-1000 m and 1000-7000 m.(3)Based on the model of oil viscosity under variable depth,the calculation models for the leakage and power loss of the deep-sea piston pump was established,which were used to analyze the leakage and power loss of the piston pump.The volumetric efficiency of the piston pump rose nonlinearly with the increase of water depth,and the upward trend gradually decreased from rapid to slow;the mechanical efficiency decreased with the increase of water depth in the form of a lower parabola,and the magnitude of decline decreased from large to small,and finally tended to be stable.It was pointed out that the changing law of the volumetric efficiency and the mechanical efficiency of the piston pump were caused by the "three-stage" variation law of hydraulic oil.The change law of the total efficiency of the deep-sea piston pump was obtained after synthesizing change rules,indicating that the total efficiency rose slowly with the increases of water depth,then rapidly decreased,and finally fell steadily;related research results laied a foundation for energy consumption analysis of deep-sea power sources..(4)Established a deep-sea piston pump simulation model which was used to simulate and analyze the pressure and flow control system of the piston pump.When considering the combination of viscosity and elastic modulus,the stability of the system increased with the increase of water depth,and the response speed decreased at the same time.The simulation results are basically consistent with the previous theoretical analysis.However,there was a certain difference in the 0-1000 m water layer,mainly due to the difference between the theoretical model and the simulation model.It can be seen that the simulation study provided a feasible method for the performance analysis of the hydraulic system under the deep sea.In this paper,the study on the parameters change law of hydraulic oil viscosity,elastic modulus,and its influence on the control characteristics and efficiency of piston pump in deeping environment provided the basis for the development of deep sea hydraulic power source,and provided good theoretical support for the choice of hydraulic medium.