用于超声速旋流分离器中的超声速喷管研究

超声速旋流分离器是一种免加热或免加注防冻剂的新型天然气脱水和重烃分离装置，喷管是其关键部件。针对超声速旋流分离器中拉伐尔喷管的特点，对3种不同的喷管设计方法进行了对比分析。结果表明：亚声速收缩段为维托辛思基曲线、喉部为一段光滑圆弧、超声速扩张段按富尔士法设计的喷管出口气流均匀，达到设计的马赫数要求。数值模拟表明，天然气在喷管内绝热膨胀形成超声速气流，在喷管扩张段水和重烃组分凝析。喷管内极短的滞留时间不会形成水合物，亦不需添加防冻剂。

THE NOZZLE USED IN SUPERSONIC SWIRLING SEPARATORS

The supersonic swirling separator is a new apparatus which can be used to condensate and separate water and heavy hydrocarbons from natural gas without heating and injecting antifreezing agent. The nozzle is the key part of the separator. According to the characteristics of the supersonic nozzle in the supersonic swirling separator, this paper presents three optimum designing methods for the Laval nozzle. Subsonic convergent section of the Laval nozzle was designed according to the Витощинский method, the throat part was designed as a smooth circular arc, and supersonic divergent section was designed according to the Foelsch method. The stream from this type of nozzle had uniform velocity with designed Mach number. As what has been shown by the simulation results, the saturated feed gas was induced to flow at supersonic velocity by a fast isentropic expansion in a nozzle, the condensation of water and hydrocarbon occured in the divergent section. Neither hydrates could be formed during extremely short resident time, nor could antifreezing agent be injected.