Theoretical modeling and multi-parameter influence analysis of piston wind in the ultra-high-speed elevator hoistway

The high-speed airflow generated when an ultra-high-speed elevator runs in the hoistway will cause a significant piston effect. Therefore, it is essential to study the variation law of the piston wind in the hoistway and the influence of different parameters on the piston wind in the hoistway. This paper first establishes the theoretical model of the piston wind in the hoistway when the elevator ascends, descends, and intersects based on the unsteady flow theory of the Bernoulli principle. The effectiveness and accuracy of the theoretical model are verified through experimental measurements and numerical simulations. Second, based on the verified theoretical model, the influence of the five parameters of the car speed, car height, hoistway height, blockage ratio, and frictional resistance coefficient on the variation law of the piston wind and ventilation rate in the hoistway is systematically analyzed. Integrating the five parameters, a multi-parameter universal theoretical formula for hoistway ventilation rate is proposed. Finally, a gray correlation analysis is performed on each influencing parameter, which showed that the piston wind in the elevator hoistway is most affected by the blockage ratio, followed by the car speed, hoistway height, and frictional resistance coefficient, and is least affected by the car height.