拉瓦尔喷管结构模式对超音速射流流动特性的影响

Effect of Laval nozzle structure on behaviors of supersonic oxygen jet flow field

首先对喷管内流动特性进行了研究,结果表明传统拉瓦尔喷管在喷管内部易形成大量明显的波系结构,抑制了超音速氧气射流的初始冲击效果,而利用特征线设计的曲线拉瓦尔喷管可有效解决该问题.其次,分析了不同供氧流量下,传统拉瓦尔喷管及曲线拉瓦尔喷管在高温条件下的射流马赫数分布、动压及射流卷吸特性.研究结果表明基于特征线法设计的曲线拉瓦尔喷管应用于转炉氧枪喷头时,可延长氧气射流核心段长度,增大氧气射流对熔池的搅拌能力,并提高氧气在熔池内的传质效果.

The blowing of oxygen at supersonic velocity through nozzles is a fundamental method and key technology for basic oxygen furnace process used in the steelmaking process.During the process,the high-speed oxygen jets penetrate the liquid slag leading to the formation of the impaction cavity on the surface of the molten bath.Further,the dynamic energy and mass transfer would occur at the three-phase(oxygen–liquid slag–molten steel)region.As a result,the impurity elements are removed,the temperature of molten bath is controlled,and the solid slag is melted faster.Moreover,many complex wave structures are formed in the traditional Laval nozzle depending on its gas flow field,resulting in suppression of the initial stirring ability of the oxygen jet.However,the new Laval nozzle designed by the characteristic-line method can solve this problem.Additionally,Mach number,dynamic pressure,and entrainment phenomenon of both traditional and new Laval nozzle structures were tested using various oxygen flow rates at the high-temperature ambition environment.The results prove that the new Laval nozzle structure prolongs the velocity core length of oxygen jet,increases the molten bath stirring effect,and improves the mass transfer process.