Study On Spatial Pipeline Routing And Energy Loss Of Complex Hydraulic Pipelines With High Pressure And Big Flow

The hydraulic pipeline is an important part of the hydraulic system,which can transmit the energy in space.As hydraulic equipment becomes more and more complex,and continues to develop in the direction of high pressure,large flow,and energy saving,the pipeline routing is also facing more new challenges.Reasonably use the limited space and make the pressure loss smaller has become the main task of the pipeline routing.Base on theoretical research and engineering application research,this paper conducts analysis on key technologies related to pipeline routing and energy loss of high-pressure and large-flow complex pipeline systems.The high-pressure and large-flow pipelines have rough shape,are not easy to bend,and occupy a large space.A pipeline routing method based on spatial coordinates is proposed.The combined configuration of the steel pipe and the hose realizes the connection between any oil ports.The S-shaped path of the hose,as a flexible unit compatible with deviations,is the key and difficult point of the entire path routing.First,there is a bending limit for the S-shaped hose,and the performance of the hose is studied based on the pressure-bearing capacity.The results show that the minimum curvature of 9±1 can make the pressure-bearing utilization rate reach more than 93%.Then,the spatial range of the S-shaped hose that can be connected is analyzed,and the spatial coordinate area of the S-shaped hose path is obtained,and any S-shaped hose path routing can be carried out in this area.In order to obtain the reserved amount of hose length,a method for calculating the length with minimum bending is proposed,and the reserved amount of hose length is calculated within the limit of the minimum bending radius.Finally,through the example of the path routing for the power head of the rotary drilling rig,a path routing scheme based on S-shape is designed,and the length of the pipeline is calculated.90° circular pipe bend is a typical structural feature in hydraulic pipeline routing.The study of its internal flow is helpful to understand the performance of pipeline and provide a theoretical basis for pipeline design.Complex phenomena of flow separation and secondary flow are obtained by numerical simulation.The separation point and the reattachment point in flow separation are less dependent on Reynolds number,but more dependent on the curvature ratio of the pipe bend.When curvature ratio >1,the backflow disappears and the flow separation is suppressed.The energy loss mechanism in pipeline is studied by effective work analysis.Flow separation,secondary flow and dean vortex cannot do effective work,and they are the reason of energy loss caused by the flow through a 90° circular pipe bend.The way to reduce energy loss is to keep elbow curvature >1 and prefer larger curvatures when space permits.Confluence and distribution of multi-branch pipeline(CDMBP)can effectively reduce pipeline density and improve space utilization,but unreasonable structural design can easily cause too much pressure loss and excessive flow distribution difference.A numerical method for the optimal design about CDMBP is proposed in this paper.The paper studies the influence law of multiple parameters,including Reynolds number,outlet and inlet area ratio,closed cavity length at the end of the common chamber,branch pipe spacing and the number of branch pipes,on the flow distribution and pressure loss with parametric analysis.The results show that: there is a pressure recovery zone in the confluence and diversion cavity,which has an impact on the flow distribution and pressure loss of each branch;the Reynolds number has an impact on the flow distribution;the increase of the Reynolds number may increase the pressure loss and the difference of flow distribution;the influence of flow distribution and pressure loss from the length of the end common chamber is negligible;the outlet and inlet area ratio,branch pipe spacing,and the number of branch pipes are importantly related to flow distribution and pressure loss.These factors need to be comprehensively considered in the optimization design of the pipeline structure.These results can be used to guide the optimal design of the CDMBP.Combined with the research of the flow distribution in the main valve oil return pipeline system of the excavator,the research was carried out on the problems of unclear flow distribution and difficult control of the pressure loss.Through the method of experimental test and simulation analysis,the characteristics of the resistive elements such as check valve,radiator,pipeline and oil tank in the two branches are obtained.When the total flow rate changes,the flow distribution of the two branches cannot be fixed at the same ratio,but the limit of the flow rate of the branch with the radiator can be kept unchanged and the resistance becomes larger when the flow is large.The check valve has been optimally configured.The results show that: at low temperature,most oil is directly returned to the tank without cooling by the radiator,which is conducive to the temperature of the oil;when the temperature is high,most oil is cooled by the radiator;when the total flow is large,the flow of the branch containing the radiator can be kept constant,and the flow of the other branch can be kept constant.The total flow changes dynamically;each working condition can keep the pressure loss within a reasonable range.Finally,the research content of the full text is summarized,and further research work is briefly discussed.The research work focuses on the spatial path routing of the pipeline and the energy loss.Under the condition of high pressure and large flow,the research is carried out from the two dimensions of the pipeline diameter and length,which are mutually restricted,and obtained a reasonable path routing and less energy loss for pipeline design method.