An Analysis On Dynamic Characteristics Of Hydraulic Support's Liquid Pipeline

As a key equipment for the fully-mechanized face, hydraulic support's working property decides the fully-mechanized face production efficiency. With the increase of supporting hight, working resistance and hydraulic system's pressure and flow, the request of pipeline characteristic is higher, but for now, it is relative lack of analysis on effect of pipeline. Therefore, it is necessary to do research about the pipeline of hydraulic support, and to put forward a set of effective pipeline design criteria. Taking the hydraulic support's liquid pipeline as research object, this paper analyzed the static and dynamic properties of pipeline, and provided theoretical reference for the chose of pipeline in engineering.The hydraulic support system of fully-mechanized working face was stated in detail. Then the author analyzed various working conditions of emulsion pump and hydraulic support. Based on this, taking a certain type of hydraulic support with two props as example, this paper calculated the pressure loss of pipeline system under the trapezoid piping mode with different diameter pipes, it provides a theoretical reference to choose pipe in practical production. This paper mainly discussed the long-distance pipeline's influence on support hydraulic system, therefore the building of pipeline model was crucial. The distributed parameter model and lumped parameter model had been established in Simulink, and a comparative analysis on various pipe models was made. Finally the suitable model for this topic was put forward.The hydraulic critical components'transient simulation models were established in Simulink, including emulsion pump, relief valve, manoeuvring valve, hydraulic cylinder etc, and the transient simulation model of support hydraulic system was set up according the chamber coupling principle. By changing the pipeline's various parameters in Simulink, this paper investigated the influence of pipe's length, diameter and modulus of volume elasticity on the prop. The simulation results show that the prop's response time to start rising is proportional to pipe's length, the response time which is needed is equal to the pressure wave's two laps of transmit time in pipeline. The time which is needed when system's pressure achieved to the setting value will increase with the increasing of pipe's length, but they are not linear relationship. Support's prop rising speed curve's response time and overshoots are proportional to the pipe's diameter. With the increasing of pipe's diameter, the time which is needed when prop's low vena pressure reached to the setting value will increase, and hydraulic system's stability will become poor, but it is favorable to the increase of prop's beginning hold pressure and the decreased of system pressure loss. The prop's ascending speed will be faster with the increasing of pipe material's volume elastic modulus, and the influence will be obvious if the pipe material's volume elastic modulus is similar to the emulsion's.The frequency simulation model of support hydraulic system was established, and the system's frequency characteristic was simulated using transfer function modules in Simulink. Finally, the author analyzed the influence of pipe's parameters on support hydraulic system's amplitude and phase frequency characteristic curve.The research work of this paper provides an important reference for the pipeline choice of hydraulic support, the modeling and simulation methods involved in this paper can provide reference for the study of dynamic characteristics of other hydraulic systems.