文 闯，曹学文，杨 燕，张 静

（中国石油大学储运与建筑工程学院，山东 青岛 266555）

研究开发

环形超声速喷管内天然气流场特性

文 闯，曹学文，杨 燕，张 静

（中国石油大学储运与建筑工程学院，山东 青岛 266555）

依据角动量守恒原理设计了一种用于天然气脱水的环形超声速喷管，建立了相应的物理和数学模型，并采用RNG k-ε湍流模型对喷管内天然气流场特性进行了数值计算。结果表明，天然气进入环形超声速喷管后发生膨胀降温，在喷管出口处马赫数可达1.85，温度低达－70 ℃，天然气经旋流叶片产生旋流，离心加速度最大可达640 000g，在低温和旋流场的联合作用下，天然气中的水凝结成液滴并被甩向管壁，实现天然气脱水。与传统的拉法尔喷管不同的是，中心体的存在可以有效地加强旋流，但同时旋流效应会降低喷管的膨胀制冷性能。

环形喷管；超声速；旋流；天然气流场

Abstract：A new annular supersonic nozzle was designed for natural gas dehydration based on the principle of conservation of angular momentum. Corresponding mathematical and physical models were established. The flow characteristics of natural gas in the annular supersonic nozzle were numerically simulated with the RNG k-εturbulence model. The results showed that natural gas expanded to supersonic velocity，resulting in a low temperature in the annular nozzles. The Mach number could reach 1.85 at a low temperature of －70 ℃ at the nozzle exit. The swirling motion was generated by the vanes located at the entrance of the nozzle，leading to a centrifugal field of about 640 000g. Water could be condensed and removed from natural gas under the combined effects of low temperature and strong centrifugal field. The strong swirling flow could be obtained in the annular nozzle as a result of the central body. When the swirling flow passed through the nozzle，the expansion characteristics of the nozzle was weakened，which was different from the common Laval nozzle.

Key words：annular nozzle；supersonic；swirling flow；natural gas flow field

从井口开采的天然气含有大量的饱和水蒸气，在天然气集输和处理过程中，当温度降至天然气露点温度时，饱和蒸汽便会凝结形成液态水，从而降低管道输送能力，增大动力消耗；与烃结合形成水合物引起管道及阀门的堵塞，与H2S和CO2等酸性气体作用加速管道和设备的腐蚀。目前常用的天然气脱水技术包括J-T阀和透平膨胀机低温脱水、三甘醇脱水及分子筛脱水等技术[1]。超声速旋流分离技术是近年来用于天然气脱水的新工艺[2-3]，相对于传统的天然气分离技术，超声速旋流分离技术具有密闭无泄漏、无需化学药剂、结构紧凑轻巧、简单可靠（无转动部件）、投资和使用成本低、支持无人值守等优点，在当今注重节能减排的大环境下，有着极为广泛的发展空间。……