Research On Aerodynamic Characteristics And Parameter Sensitivity Analysis Of Ultra-high-speed Elevator Shaft Under The Action Of Induced Airflow

With the progress of society,urban buildings are gradually developing to super high-rise buildings,which creates opportunities for the rapid development of ultra-high speed elevator technology.However,due to the narrow and relatively closed running space of elevator,the increase of speed increases its piston effect,which brings a series of aerodynamic problems,such as aerodynamic noise,wind-induced vibration and aerodynamic resistance.This will not only lead to the damage of some precision components in the elevator system,but also reduce the ride comfort of passengers.Considering the rapid development of computational fluid dynamics and the emergence of advanced computer equipment,the advantages of strong visualization and high calculation accuracy of numerical simulation research methods are gradually emerging.Taking numerical simulation as the main research means and test as the auxiliary verification,this thesis makes an in-depth exploration on the aerodynamic characteristics of the hoistway from the three aspects of airflow movement in the hoistway,car aerodynamic force and aerodynamic noise,which provides important guiding value for the subsequent researchers who study the aerodynamic characteristics of the ultra-high-speed elevator hoistway,and greatly improves the deficiencies in the three-dimensional numerical simulation of the elevator.Firstly,this thesis briefly introduces the basic solution and related contents of numerical simulation.At the same time,considering the hoistway structure and design,a multi parameter general model of ultra-high-speed elevator is constructed.Based on this model and CFD numerical simulation method,a multi-region dynamic layered method of ultra-high-speed elevator is proposed.Furthermore,the movement of the unsteady airflow in hoistway with different numbers of ventilation holes and the interaction between the ventilation holes are then analyzed.Finally,the effects of the number,location and cross-sectional area of ventilation holes on the air movement are analyzed,and the optimal opening positions of one pair and two pairs of ventilation holes are discussed.Secondly,based on the 120 m ultra-high speed elevator test tower of the elevator cooperative manufacturer,an experimental platform for aerodynamic characteristics of ultrahigh-speed elevator hoistway is built,and the wind speeds at the lower entrance,middle height and upper exit of hoistway are measured by GM8902 digital anemometer.Taking the specific parameters of the manufacturer's actual elevator as the input parameters,the theoretical analysis and numerical solution are carried out respectively,and the wind speed data at the entrance under the hoistway obtain from the test were compared with the theoretical solution results and numerical simulation results.In order to achieve better verification effect,the wind speed data at the middle height of the hoistway and the upper outlet obtained from the test are compared with the numerical simulation results,which fully verified the effectiveness of the general model and the multi region dynamic stratification method,and also provides an important guarantee for the reliability of the follow-up research.Then,based on the verified multi parameter general model and multi-region dynamic layering method of ultra-high-speed elevator,the variation laws of aerodynamic drag,aerodynamic lift and hoistway pressure in hoistway with or without ventilation hole are analyzed respectively.On this basis,the effects of the changes of seven main parameters of vent position,angle,shape,length,cross-sectional area,hoistway blocking ratio and car height on aerodynamic force and hoistway pressure are analyzed respectively,the formation mechanism and change law of low-speed circulation area at the connection between vent and hoistway are explored,and the optimal design suitable for weakening hoistway aerodynamic problem is put forward on this basis.The analysis of the influence of different hoistway parameters on the aerodynamic characteristics in the hoistway provides important guidance for the technical staff in the design of ultra-high-speed elevator hoistway.Finally,based on the verified multi parameter general model of ultra-high-speed elevator,the turbulence acoustic model and ultra-high-speed elevator three-dimensional numerical wind tunnel model which can solve the flow field in similar hoistway are constructed.The pulsating flow field and aerodynamic noise caused by ultra-high speed elevator car are numerically studied.The vortex structure and flow field asymmetry around the car are analyzed by using the instantaneous velocity and instantaneous vorticity of air flow in the wind tunnel model.On this basis,the variation law of SPL on the windward side and leeward side of the car with the running speed is analyzed,and the noise attenuation and spectrum characteristics are explored.