Study On Gas-Solid Coupling Vibration Characteristics Of High-Speed Elevator Hoisting System

With the continuous emergence of high-rise and super-high-rise buildings,high-speed and long-stroke become the inevitable trend of elevator development.The higher the speed of elevator,the stronger the vibration problem will be.Under the constraints of building space and elevator rated load,the architects usually design the elevator shaft very compactly,thus forming a narrow operating environment of the elevator car.In this operating environment,the car will have a severe impact on the surrounding airflow when moving at a high speed.At the same time,the drastic change of flow field will also react on the lifting system and affect the vibration state of the car,making the gas-solid coupling vibration response between the airflow in the shaft and the hoisting system more remarkable,which will further affect the comfortable,stable and reliable operation of the elevator.Therefore,exploring the gas-solid coupling mechanism between the airflow and the high-speed elevator hoisting system in the real service environment and deeply analyzing the dynamic response characteristics of the gas-solid coupling horizontal vibration of the hoisting system in this environment will have a great theoretical and engineering practical significance for the design,manufacture of high-speed elevator and the development of vibration absorber.Firstly,on the basis of the computational fluid dynamics theory,the complex flow characteristics of the airflow in the shaft during the operation of high-speed elevator are analyzed,and the three-dimensional governing equations of the flow field in the shaft and its corresponding discrete format and solving algorithm are established.The dynamic model of the high-speed elevator hoisting system is established based on its motion characteristics.Furthermore,by analyzing the interaction between the hoisting system and the airflow in the shaft at the interface,the coupling mechanism between them is explored.Based on the idea of time discretization,a gas-solid coupling vibration analysis method for high-speed elevators,the gas-solid interaction coupling analysis method,is proposed.In this method,the equivalent aerodynamic loads of the high-speed elevator hoisting system at all time steps are calculated and applied to the dynamic model of the hoisting system,and the coupling response between high-speed elevator hoisting system and airflow is realized by solving the model iteratively in each time step.This method not only improves the deficiencies of the existing research on the horizontal vibration characteristics of high-speed elevators,but also opens up a new research idea and direction for the its future research.Secondly,the equivalent aerodynamic loads on the car at different running speeds are numerically solved,and the relationship between the running speed,the lateral translational displacement,the deflection angle of the high-speed elevator and the concentrated lateral force,and the concentrated moment are explored.Based on Langrage's equations and the excitation model of guiding system,the horizontal vibration dynamic model of airflow-car coupling system of high-speed elevator is established.In a case,the horizontal vibration acceleration response of airflow-car coupling system at different running speeds is solved based on the model,and the typical digital characteristics of horizontal vibration acceleration under coupling and uncoupled conditions are compared and analyzed.The influence of vibration state parameters on the dynamic response of the coupling system is analyzed and studied,which provides a certain theoretical guidance for the design and active vibration control of high-speed elevators.Thirdly,the relationship between the elevator blockage ratio,deflection angle,concentrated lateral force and concentrated moment of the high-speed elevator is explored by numerically solving the equivalent aerodynamic loads on the car under different blockage ratios.Based on D'Alembert's principle and Euler-Bernoulli beam theory,the dynamic equations of car,car frame,guide roller and guide rail of high-speed elevator are established respectively,and the dynamic model of airflow-car-guide rail coupling system of high-speed elevator based on different blockage ratio is established by exploring the relationship between airflow and them,which improves the existing dynamic model of high-speed elevator.On the basis of the established dynamic model,the horizontal vibration acceleration response at the center of the car bottom under different blockage ratios is analyzed through a case,and the typical digital characteristics of horizontal vibration acceleration under the coupling state and uncoupling state are compared and analyzed,which provides a theoretical support for the design of blockage ratio of high-speed elevators.Finally,with the help of the 120 m elevator test tower of Shandong Fuji Elevator Co.,Ltd.,a 7m/s high-speed elevator test platform is built.Taking the measured parameters of the elevator as the input parameters of the dynamic model in Chapter 4,the horizontal vibration acceleration response at the center of the car bottom is simulated numerically with MATLAB.The horizontal vibration acceleration response of the elevator is measured on the test platform by using DT-4A elevator acceleration tester.The typical digital characteristics of measured and simulated horizontal vibration acceleration are compared and analyzed,which directly or indirectly verifies the correctness of the gas-solid coupling vibration analysis method and the corresponding dynamic models proposed in this paper.