不同喷管背压下氨气超声速凝结特性  

Supersonic condensation characteristics of ammonia under different nozzle back pressures

作　　者：边江[1] 赵子源 陈俊文 郭丹 刘杨[1] 曹学文[1] BIAN Jiang;ZHAO Ziyuan;CHEN Junwen;GUO Dan;LIU Yang;CAO Xuewen(College of Pipeline and Civil Engineering,China University of Petroleum(East China),Qingdao 266580,Shandong,China;Southwest Branch of China Petroleum Engineering Construction Co.,Ltd.,Chengdu 610031,Sichuan,China)

机构地区：[1]中国石油大学(华东)储运与建筑工程学院,山东青岛266580 [2]中国石油工程建设有限公司西南分公司,四川成都610031

出　　处：《低碳化学与化工》2023年第6期127-133,共7页Low-Carbon Chemistry and Chemical Engineering

基　　金：国家自然科学基金(52104071,52074341);中国博士后科学基金(2022M723497)。

摘　　要：氨分解制氢是“氨-氢”储运产业的重要组成。由于氨的催化分解效率有限,分解气中往往含有未分解的氨气,因此氨气与氢气的分离是必不可少的环节。将超声速旋流分离技术引入“氨-氢”分离领域,建立了考虑氨气非平衡凝结与激波的超声速凝结模型,研究了氨气在Laval喷管内的凝结流动特性,探究了喷管背压对氨气的超声速流动与凝结特性的影响。结果表明,氨气在Laval喷管中高速膨胀,在通过喉部后达到凝结临界状态,在极短的距离内成核并大量凝结,液滴半径和液相质量分数不断增大。激波产生后,过冷度迅速降为负值,凝结液滴开始大量蒸发。在激波串的波节间存在低温区,当过冷度大于0 K时液滴半径小幅增大,但之后又会快速蒸发。当压比(出口背压与进口静压的比值)由0.18增大至0.62,Laval喷管出口处液相质量分数从0.064减小至0,Laval喷管液化效率不断减小直至完全失去液化能力。Ammonia decomposition to produce hydrogen is an important part of the“ammonia-hydrogen”storage and transportation industry.Due to the limited efficiency of the catalytic decomposition of ammonia,the decomposition gas often contains undecomposed ammonia,so“ammonia-hydrogen”separation is an essential step.Introducing supersonic separation technology to the field of“ammonia-hydrogen”separation,a supersonic condensation model considering the non-equilibrium condensation of ammonia with surge waves was developed,and the condensation flow characteristics of ammonia in Laval nozzles were investigated,and the effects of outlet pressure on the supersonic flow and condensation characteristics of ammonia were explored.The results show that ammonia flows in the Laval nozzles and expands at high velocity,reaching a critical state of condensation after the throat,and nucleates and condenses extensively within a very short distance,and the droplet radius and liquid phase mass fraction continue to increase.After the shock wave occurs,the subcooling rapidly drops to a negative value and the condensed droplets begin to evaporate in large quantities.There is a low temperature zone between between the knots of the surge string.The droplet radius will slightly increase when the subcooling is greater than 0 K,but it will then evaporate rapidly.As the pressure ratio(ratio of outlet back pressure to inlet static pressure)increases from 0.18 to 0.62,the mass fraction of the liquid phase at the Laval nozzle outlet decreases from 0.064 to 0,and the Laval nozzle liquefaction efficiency continues to decrease until it loses its liquefaction capacity completely.

关 键 词：Laval喷管 氨气 凝结 背压 激波 

分 类 号：TK91[动力工程及工程热物理]