Study On Gas-solid Coupling Horizontal Vibration Response Of High-speed Elevator Car In The Whole Process Of Operation

With the continuous advancement of urban modernization,the urban population has increased significantly.High-rise buildings,which have been increasingly seen in response to an increase in population,are resulting in more and more demand for elevators that are longdistance,and high-speed.It is shown that the complex flow of shaft currents occurs with the increase of speed in a narrow long distance shaft room and the interaction effect is seen between shaft airflow and shock,which further amplifies the horizontal vibration response of the highspeed elevator.Meanwhile,in practice,the high-speed elevator car goes through a cycle of variable acceleration,uniform speed,and variable deceleration process.The changing of the car’s running speed directly impacts the motion of shaft airflow and the horizontal vibration response of the car,influencing the stability,safety and ride comfort of the elevator.When studying the effect of the shaft airflow loads on the horizontal vibration response of the car in each process,analyzing the reasons for inducing the differential performance of the horizontal vibration response of the car,and discussing the impact of shaft-car parameter changes on the horizontal vibration response of the car,they have important theoretical guidance value and engineering value in improving the vibration reduction strategy during the entire operating process.The key studies in this thesis are as follows:Firstly,aiming at the horizontal vibration response of the car during the operation in a real service environment,a fluid simulation model of the high-speed elevator shaft was constructed based on computational fluid dynamics,and the aerodynamic load during the whole operating process of the car was calculated by using the dynamic grid technology.The initial random displacement excitation of the guide rail was generated by Gaussian white noise,and correction coefficients based on the running speed of the car and the horizontal aerodynamic force of the shaft fluid were introduced.Then,based on the Hertz elastic contact theory,the approximate expression of the random contact force of the time-varying guide rail was deduced,and the external coupling excitation model of the whole process of car operation was established.Those provided a model basis for further exploring the gas-solid coupling horizontal vibration response characteristics of the high-speed elevator car.Secondly,considering the random contact excitation of the shaft fluid aerodynamic load and the guide rail,a six-degree-of-freedom gas-solid coupling dynamics calculation model for the whole process of high-speed elevator car operation was established based on the Lagrange principle and rigid body dynamics equations.The horizontal vibration response of the car at different operating speeds during the lifting process was solved.A 7m/s high-speed elevator horizontal vibration response test platform was built.This study measured the horizontal vibration acceleration at the diagonal intersection of the car floor using the DT-4A elevator vibration response tester and exported the horizontal vibration acceleration data of the elevator during the entire upward process through supporting software.The validation of the gas-solid coupling horizontal vibration calculation model for the entire process of high-speed elevator operation was completed by comparing and analyzing the typical digital eigenvalues,which were obtained from the vibration response data from the experiment and the model simulation.Then,based on the different operating characteristics of the car acceleration uniform deceleration process,the effect of shaft-induced airflow load on the horizontal vibration response of high-speed elevator cars in each process was studied.The reasons for the differential performance of the car’s horizontal vibration response were analyzed.It provides theoretical support for developing vibration reduction strategies throughout the entire operation process of high-speed elevators.Finally,combined with the external coupling excitation model of the entire high-speed elevator car operation process,a three-degree-of-freedom transient dynamic model of gas-solid coupling on the asymmetric side of a high-speed elevator was established based on the Lagrange principle and Newton’s second law.The Newmark-method was used to solve the model and obtain the horizontal vibration response results of the asymmetric side of the car.Then,using five types of shaft blockage ratios and three types of carloads as calculation conditions,the influence of two types of shaft-car parameter changes on the horizontal vibration response of the asymmetric side of the car was analyzed.It provides theoretical guidance for technical staff in the design of active vibration dampers and shaft structures for high-speed elevator cars.