Study on Pressure Coefficient in Process of Double Slot Nozzle Jet Impingement on Sinusoidal Colliding Strip

双缝隙喷嘴射流冲击正弦形状带材过程压力系数的研究

¹ School of Automation, Northwestern Polytechnical University, Xi’an, 710072, China
² School of Information and Electrical Engineering, Hebei University of Engineering, Handan 056038, China

Received: 20 May 2018

Abstract

Air cushion furnace is widely used in the heat treatment process of aluminum strip, copper strip and silicon steel, and the double slot nozzle is the core part of the air cushion furnace device. Studying the distribution characteristics of the surface pressure coefficient of the strip during the suspension process could provide important theoretical references for the high-efficiency and high-value production of the air-cushion furnace. In this paper, the distribution of pressure coefficients is studied under the conditions of Re=48 194~12 048, high H/D=1~3, spacing L/D=17.2 and sinusoidal amplitude A=0~30 mm. The results show that with the decrease of L/D, the position of the main stop point moves to the center line of the nozzle, and the value of the second stop point increases gradually, and with the increase of the sinusoidal amplitude A, the position of the main stop point moves gradually to x/D=0. The pressure coefficient C_p decreases with the increase of sinusoidal amplitude A, the pressure coefficient C_p decreases with the increase of H/D, and the difference between the pressure coefficient at the stationary point of the double-slot nozzle and the pressure coefficient at the non-stationary point increases with the increase of H/D. This study provides an important theoretical basis for the design of double slot nozzles in air cushion furnace.

摘要

气垫炉广泛应用于铝带、铜带和硅钢的热处理过程，而双缝隙喷嘴是气垫炉装置的核心部件。研究悬浮带材表面的压力系数分布特性，可以为气垫炉的高效高值生产奠定重要理论依据。研究了Re=48 194~12 048、高度H/D=1~3、间距L/D=17.2和正弦幅值A=0~30 mm时，双缝隙喷嘴射流冲击正弦形状带材表面的压力系数分布规律。研究结果表明：雷诺数Re对压力系数C_p以及主驻点与第二驻点的压力系数差值影响并不明显；压力系数C_p随着H/D的增大而减小，而双缝隙喷嘴驻点处的压力系数与非驻点处的压力系数差值随着H/D的增大而增大。随着正弦幅值A的增大，主驻点位置逐渐向x/D=0移动；压力系数C_p随着正弦幅值A的增加而减小；随着L/D的减小，主驻点位置向喷嘴的几何中心线移动，第二驻点的压力系数逐渐增大。