Research on the drags of high speed elevator with different height diversion cover

The three-dimensional flow of high speed elevator is numerical simulated using the Computational Fluid Dynamics Method (CFD). The car of high speed elevator has dimensions of length 2.3m, width 1.7 m and height 2.4 m. The shape of diversion cover is conic. The flows of high speed elevator with different height diversion cover are simulated, and then the drags are analyzed. It is present that the drags of the car are decreased when the height of diversion cover increases. Introduction A large amount of high buildings are built with the rapid development of China economy, the height of high buildings is generally achieved 500 m. One of the highest buildings is ShangHai Tower[1], the building stands 632 m high and has 123 stories. Thus the high speed elevator systems (over 2m/s) have been predominantly required in China. However, with the increase of the elevator speed, the problems of high-speed stability, security, and noise need to be considered. The aerodynamic performance of high speed elevator plays an important role, and the height of the diversion cover is the key factor. Thus it is necessary to study the influences of the cover height on the elevator’s performance. The experimental method [2] and numerical method [3,4] have been performed in the aerodynamic performances analysis and the car geometry optimization. However the costs of the experiments are much higher, the Fluent and the CFX Software have been widely used in the numerical simulation with the numerical method been matured [5]. The turbulent flows and aerodynamic performances have been studied using the CFD method. The forces and fluid-structure coupled vibrations have been studied by W.D. Zhu[6], it shows that the turbulent flow is the source of vibration. The traditional Euler equations and N-S equations have been used in the complex flow simulation of high speed elevator by So.A. T.P[7]. The diversion cover with conic surface, semi-spherical surface, and parabolic surface are further considered. The results show that the aerodynamic performance of diversion covers with conic surface is better. However the influence of diversion cover height have not been studied yet. In this paper the conic surface diversion cover of different heights are studied. then turbulent flows of the high speed elevators are simulated with Fluent. And the drags of the elevator car are studied. The evaluator model The car of the high speed elevator studied in this paper is a box with the length of 2.3m, with the width of 1.7m, and height of 2.4m. The diversion covers are built using conic surfaces with the height of 0.2m, 0.4m, 0.6m, 0.8m, 1.0m, and 1.2m, respectively. To reduce the computational cost, only quarters of the models are built, parts of them are shown in Fig 1. 4th International Conference on Mechatronics, Materials, Chemistry and Computer Engineering (ICMMCCE 2015) © 2015. The authors Published by Atlantis Press 2366 a) Without cover b) h=0.4m c) h=0.8m d) h=1.2m Fig.1. High speed evaluator models with different diversion cover The elevator well has dimensions of length 3m, width 2.6m, and height 100m, as shown in Fig 2(a). The meshes are generated with structure mesh with about 267,000 cells. The meshs of diversion cover with height of 1.2m are shown in Fig 2(b), 2(c). a) Flow region b) mesh of the elevator car c) mesh of the symmetry plane Fig.2. model of elevator with h=1.2m Computation method In the Cartesian coordinate system, the three-dimensional unsteady N-S equations in a conservative differential form on a moving mesh can be written as ( ) S 0 c v Wd F F d t W ∂W ∂ W + − = ∂ ∫ ∫ d d d