【摘要】 针对制冷系统蒸发器除霜效率低的问题,设计了两种喷嘴:喷嘴1的射流收缩段为圆弧收缩,引流段和扩散段呈圆柱状;喷嘴2的射流收缩段为直线收缩,引流段和扩散段呈圆锥状。采用理论计算和数值仿真两种方法获得了入口气压在0.3 s内从0. 6 MPa快速降至0.1 MPa时的喷嘴射流参数,理论计算与数值仿真结果相近。数值仿真表明,喷嘴2的能量损失高于喷嘴1;喷嘴2的气压波动幅度大于喷嘴1;喷嘴2的出口速度优于喷嘴1。据此设计了综合两种喷嘴特点的喷嘴3,并对喷嘴3的圆弧半径作优化设计,结果表明当该半径为11 mm时,喷嘴3的射流除霜能力优于喷嘴1和喷嘴2。更多还原

【Abstract】 Aiming at the problem of low defrost efficiency of evaporator,two kinds of nozzles are designed. The contraction section of nozzle 1 is circular arc,the drainage section and diffusion section are cylindrical. The contraction section of nozzle 2 is linear,the drainage and diffusion sections are conical. The nozzle jet parameters are obtained by theoretical calculation and numerical simulation when the inlet pressure drops rapidly from 0.6 MPa to 0.1 MPa in 0.3 seconds. The results obtained by the theoretical calculation are close to the numerical simulation results. The numerical simulation results show that the energy loss of nozzle 2 is more than that of nozzle 1. The fluctuation amplitude of air pressure of nozzle 2 is higher than that of nozzle 1. The average velocity of nozzle 2 is better than that of nozzle 1. On this basis,nozzle 3 with the characteristics of two nozzles is designed,and its circular radius is optimized. The optimization result show that the defrosting ability of nozzle 3 is better than nozzle 1 and nozzle 2 when the radius is 11 mm.更多还原