质量流量对超临界裂解反应过程的影响研究  

Effect of mass flow rate on supercritical cracking reaction process

作　　者：王慧君 沈文豪 陈玉[1] 王健礼[2] 李象远[1] WANG Hui-jun;SHEN Wen-hao;CHEN Yu;WANG Jian-li;LI Xiang-yuan(College of Chemical Engineering,Sichuan University,Chengdu 610065,China;College of Chemistry,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学化工学院,四川成都610065 [2]四川大学化学学院,四川成都610065

出　　处：《化学研究与应用》2021年第5期902-910,共9页Chemical Research and Application

基　　金：国家自然科学基金项目(91641121)资助。

摘　　要：燃料质量流量是发动机热管理系统的重要控制参数。为了研究质量流量对冷却通道内燃料复杂反应过程的影响,本文基于实际气体状态方程建立了耦合详细反应机理的一维流动反应数学模型。利用该模型对质量流量0.8 g·s^(-1)、1.0 g·s^(-1)、1.2 g·s^(-1)条件下碳氢燃料在总长1.0 m通道内的吸热裂解反应进行了计算分析,结果显示由于裂解反应与流体热物性及流速存在耦合关系,燃料停留时间沿流动方向呈非线性分布。不同质量流量条件下燃料的局部停留时间在距通道进口约0.3~0.4 m处出现等值现象。质量流量较小时燃料在通道内的具有较长的总停留时间,但在主要反应阶段的局部停留时间缩短,这主要是由于裂解反应引起密度降低所致。同时,本文引入了敏感性分析方法,分析了不同质量流量时各裂解反应产物产率对质量流量变化的敏感性。结果显示,C_(3)H_(8)、C_(4)H_(8)、C_(4)H_(10)、C_(5+)、CC_(5+)五种裂解产物的产率对质量流量的敏感性系数在燃料裂解率较低时为负值,在高转化率时为正值,并且C_(2)H_(2)的敏感性系数绝对值始终最大。Mass flow rate of fuel is an important control parameter of engine thermal management system.In order to study the influence of mass flow rate on the complex reaction process of fuel in cooling channels,a one-dimensional flow reaction mathematical model coupled with detailed reaction mechanism was established based on the actual gas state equation.The model was used to calculate and analyze the endothermic cracking reaction of hydrocarbon fuel in a channel with a total length of 1.0 m at mass flow rates of 0.8 g·s^(-1),1.0 g·s^(-1) and 1.2 g·s^(-1).The results show that the fuel residence time is nonlinear distributed along the flow direction due to the coupling relationship between the pyrolysis reaction and the thermal physical property and flow velocity of the fluid.Under different mass flow conditions,the local residence time of fuel appears equivalent phenomenon at about 0.3~0.4 m away from the inlet of the channel.The total fuel residence time in the channel is longer when the mass flow rate is small,but the local residence time during the main reaction phase is shorter,mainly due to the density reduction caused by the pyrolysis reaction.At the same time,the sensitivity analysis method is introduced to analyze the sensitivity of the yield of each pyrolysis reaction product at different mass flow rates.The results show that the sensitivity coefficients of C_(3)H_(8),C_(4)H_(8),C_(4)H_(10),C_(5+)and CC_(5+)to mass flow rate are negative when the fuel cracking rate is low and positive when the conversion rate is high,and the absolute value of the sensitivity coefficients of C_(2)H_(2) is always the highest.

关 键 词：碳氢燃料 超临界 裂解反应 停留时间 敏感性 

分 类 号：O643.2[理学—物理化学]