Research On Energy Saving Method Of Variable Hydraulic System Of Full Hydraulic Boom Tower Crane

With the development of modern engineering construction toward high altitude,the construction technology becomes more and more complicated,the single component is more and more heavy,and the requirement for construction space is also increased accordingly.Therefore,the hydraulic boom tower crane,which was used as the construction machinery in high altitude and narrow space,has become the first choice since its inception.This kind of tower crane uses diesel engine as power source,which reduces the impact of large tower crane on power grid.However,the high fuel price and increasingly stringent emission standards make it urgent for the construction machinery industry to develop towards the concept of green production.In the "Central Committee of the Communist Party of China on the formulation of the 1Zth five-year plan for national economic and social development"China has also clearly pointed out that "advocate energy conservation and emission reduction "Therefore,it is particularly necessary and urgent to study the energy saving and consumption reduction of full hydraulic boom tower crane.In this thesis,the full hydraulic boom tower crane maximum lifting moment of 2400t·m is taken as the research object.During the process of luffing change,the potential energy generated by the boom is distributed to the system in the form of thermal energy to raise the temperature of the oil,causing energy loss.It will also adversely affect the performance of the system.Through the analysis and comparison of different energy recovery methods,it is determined that the hydraulic energy recovery method is used,and based on the tower crane original luff-ing hydraulic system,the pump/motor is used twice.The component and the plurality of piston accumulators are arranged in a pressure step,and a hydraulic energy-saving system suitable for energy recovery and reuse of the full-hydraulic boom tower crane luffing mechanism is designed.The potential energy generated by the boom during the lowering process is converted into oil pressure energy transfer,and then converted into internal energy storage by the piston accumulator to realize the recovery of the potential energy of the boom tower machine during the luffing process,and the recovered energy can be in the heat dissipation system.It has been reused to achieve energy saving.With the help of the plane mechanical library and hydraulic library provided by AMESim software,the load system of the luffing mechanism,the original luffing hydraulic system and the simulation model of the luffing hydraulic energy-saving system are built,respectively.Firstly,themechanical and fluid integration simulation of the original luffing mechanism hydraulic system is carried out in the plane coordinate system to verify the correctness of the load system simulation model of the luffing mechanism.At the same time,the potential energy loss of the boom,nearly 11021.8s kJ,during the change from the elevation 80 angle to the elevation 17 angle is obtained.On this basis,the parameter allocation of the energy storage elements of the energy-saving system is completed.Then the simulation analysis of the luffing mechanism hydraulic energy-saving system is carried out.The results show that the boom lowering process is more stable and the braking performance is good.The recovery rate of the boom potential energy can reach 66.67%,and the energy reuse rate can reach 50.79%.At the same time,further analyze the influencing factors of energy-saving system energy recovery,and obtain the change of accumulator gas volume,which has obvious influence on energy recovery rate and work performance of energy-saving system.The works in this thesis provides a theoretical basis for energy-saving system design of full hydraulic boom tower crane,and has significant practical reference value.