| Nowadays,the high-rise and super high-rise buildings force the city’s vertical transportation capacity to improve continuously.Elevator,as the main vertical transportation tool,is also developing towards the direction of large travel and high speed.However,the improvement of elevator speed also worsens the operation environment of the elevator,such as the vibration intensified,noise increasing,which not only reduce the ride comfort and operation safety of the elevator,but also damage the precision parts in the elevator system and reduce the life of the elevator.Moreover,the present urban construction space is tight,which makes the design of elevator hoistway narrow.This worsens the aerodynamic characteristics of the elevator,and increases the aerodynamic load on the elevator.Therefore,in order to realize the safe,comfortable and stable operation of the super high-speed elevator,it is more and more important to improve the aerodynamic characteristics of the elevator by studying the aerodynamic characteristics and the aerodynamic optimization design method.In this paper,the following research work of main existing problems of super highspeed elevators is carried out:(1)Considering that the running speed of the elevator is far below 0.3Ma,that is to say,the air flow in the hoistway belongs to the low-speed incompressible flow,so the numerical simulation in this paper adopts SIMPLE algorithm to solve the air flow in the hoistway;and continuity equation and Reynolds Averaged Navier-Stokes(RANS)equation are used as the control equations of the flow field in the shaft;as for the optimization of elevator aerodynamic shape,a multi-objective optimization design method of the air rectification cover(ARC),based on the Elliptic Curve methodOptimal Latin Hypercube Design-Radial Basis Function-NSGA-Ⅱ is presented.(2)Based on the energy method,and considering the random excitation of the guide rail and the air disturbance,a four degree of freedom dynamic model of the lateral vibration of the super high speed elevator is established,and the correctness of the model is verified by experiments;in terms of aerodynamic force(moment)calculation of super high-speed elevator,four main parameters of elevator system is selected to carry out parametric research,the parameters studied include the running speed of elevator,car offset,car deflection angle and the distance from car sidewall to hoistway wall(DCH);for the four main parameters,24 working conditions are subdivided;the aerodynamic force(moment)of the elevator car under each working condition is calculated by CFD method,and the relationship between each parameter and the aerodynamic force(moment)of the car is explored;based on this,Newmark-β method is used to calculate the effects of elevator system parameters on elevator vibration acceleration,it can be used for reference in the study of aerodynamic shape desin of super high speed elevator.(3)Considering the joint influence of time-varying characteristics of guide rollerrail contact stiffness under the aerodynamic load and the rail excitation during elevator operation,a 17 DOF dynamic model of elevator horizontal vibration is established;the GWN(Gaussian white noise)is employed to imitate the elevator guide excitation,and Savitzky Golay filter is used to filter the simulation guide excitation;based on Hertz’s Elastic Contact Theory,the guide roller-rail contact stiffness model under preload and aerodynamic force is established;in terms of aerodynamic calculation,a user define file is compiled according to the actual operation curve of the elevator,to control the movement state of the car,and the aerodynamic load data of the elevator is obtained by CFD numerical simulation;finally,using Newmark-β method,the influence of guide roller-rail contact stiffness on the horizontal vibration of elevator is studied,which provides a theoretical guidance for the selection of rubber stiffness of roller.(4)In view of the multi-objective optimization design of the optimal aerodynamic shape of the ARC of the super high speed elevator,the elliptic curve method is used to parameterize the shape of the ARC,the design variables are selected to control the deformation,and the feasible region of the ARC are determined;base on the Optimal Latin Hypercube Design(Opt.LHD)method,the initial test sample points are determined for training in the feasible region,the corresponding aerodynamic data of each initial sample point is obtained through CFD numerical simulation,and the laws of action of each design variable on the responses are analyzed;based on the Radial Basis Function(RBF)method,a surrogate model of the relationship between the shape of the ARC and the aerodynamic load is established,the optimal design is carried out by NSGA-Ⅱ algorithm,and the optimization effect of the ARC is compared and analyzed.This has certain reference significance for the optimization design of elevator ARC in the future. |
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