Optimization and Aerodynamic Characteristics of New Air-Cushion Nozzle of Floating Furnace for Automobile Body Sheet

It is very important to develop new air-cushion nozzles so as to raise the heat treatment property of aluminum alloy automobile body sheet(ABS). A geometric model of air-cushion furnace equipment of ABS was built up and flow field was simulated by using k-ε turbulence equations of COMSOL Multi-physics. The influence and regularity of number(n),diameter(d) and arrangement of middle hole,and main control parameters of new air-cushion nozzle on aerodynamic characteristics and flow field were studied. The results show that:1) with n increases,airflow vortexes in air-cushion area increase in multiple; d decreases or n increases,air cushion pressure(p_c) becomes uniform; 2) average of p_c is proportional to pressure in nozzle box(p_t),when n increases,ratio of average of p_c to p_t increases,and when n ≤ 3 and d < b / 2,they have little effect on ratio of p_c average to p_t; 3) when n is an even number,n ≥4,and d ≤ b/2,p_c shows good uniformity; when n is an odd number,the center hole affects p_c uniformity greatly,and,when diameter of center hole is less than b / 4 and diameter of non-center is between b / 4 and b / 2,p_c has good uniformity. A new air-cushion jet model was presented,and the deviation of this new model with simulation data and experimental measured data are less than 7.75% and 7.76%,respectively. The present research is valuable for improving air-cushion stability,Al strip temperature homogeneity,and temperature control precision.

It is very important to develop new air-cushion nozzles so as to raise the heat treatment property of aluminum alloy automobile body sheet （ ABS）. A geometric model of air-cushion furnace equipment of ABS was built up and flow field was simulated by using k -s turbulence equations of COMSOL Multi-physics. The influence and regularity of number （n）, diameter （d） and arrangement of middle hole, and main control parameters of new air-cushion nozzle on aerodynamic characteristics and flow field were studied. The results show that： 1 ） with n increases, airflow vortexes in air-cushion area increase in multiple ; d decreases or n increases, air cushion pressure （凡. ）becomes uniform; 2 ） average of is proportional to pressure in nozzle box （ ） , when nincreases, ratio of average of p r to in creases , and when n 3 and d 〈 b /2 , they have little effect on ratio of 凡,average to; 3） when n is an even number, n 4 , and d b / 2 ,凡. shows good uniformity; when n is an odd number, the center hole affects Pc uniformity greatly, and, when diameter of center hole is less than b/4 and diameter of non-center is between b/4 and b/2 , p has good uniformity. A new air-cushion jet model was presented, and the deviation of this new model with simulation data and experimental measured data are less than 7.75% and 7.76%, respectively. The present research is valuable for improving air-cushion stability, Al strip temperature homogeneity, and temperature control precision.