反应扩散对流体系前沿波失稳的表面活性剂效应
发布时间：2019-03-19 14:45
【摘要】：化学反应和输运过程的耦合产生复杂的化学时空动力学现象,如前沿波、脉冲波、呼吸波和图灵结构等。自催化化学反应与扩散的耦合,将产生化学前沿波。在化学波的前沿和波后发生的化学反应和产生的化学反应热,将带来溶液中溶质变化和温度变化,使得系统中的物理量,如密度、表面张力、粘度等发生变化,产生相应的梯度。这些梯度的产生会引入不同的对流,例如,密度梯度将引起溶液整体的浮力对流,而表面张力梯度将引起溶液气液界面上Marangoni对流。亚氯酸盐-连三硫酸盐反应体系是典型的放热自催化反应体系,其自催化剂是氢离子,且连三硫酸盐在碱性溶液中不易水解。本文通过控制实验条件,深入研究了亚氯酸盐-连三硫酸盐反应-扩散-对流前沿波的失稳现象,以及在前沿波失稳中的表面活性剂效应。在理论研究中,使用耦合的多物理场方程模拟前沿波失稳行为,从而分析失稳产生的动力学机理。实验探究了亚氯酸盐-连三硫酸盐放热自催化反应前沿波在长方体型反应器中水平传播时受到的对流影响。首次在实验中观察到前沿波在浮力对流影响下的振荡传播。并且前沿波速度与反应物浓度和溶液高度有关。实验中通过引入四种表面活性剂,分别是十二烷基苯磺酸钠、曲拉通X-100、硫代甜菜碱12和十二烷基硫酸钠,探究了前沿波失稳中的表面活性剂效应。当加入十二烷基苯磺酸钠时,前沿波上出现多对流卷,并且前沿波前后的温度变化与其浓度有关。而十二烷基硫酸钠的加入使得体系中的热效应减弱,前沿波的形态表现为产物在反应物下方。除了十二烷基硫酸钠,其他三种表面活性剂浓度的变化会对前沿波的速度和最大混合长度产生影响。并且,在加入十二烷基苯磺酸钠的实验中,前沿波波速与反应物浓度和溶液高度有关。在数值模拟中,利用不可压缩的Navier-Stokes方程、反应-扩散方程和传热方程三者的耦合,模拟了放热自催化反应前沿波在对流影响下的失稳行为,包括浮力对流主导下的前沿波振荡传播,以及浮力对流和Marangoni对流耦合作用下的前沿波失稳。同时,考察了浮力对流中密度温度系数,Marangoni对流中表面张力温度系数及其他变量对前沿波失稳的影响。
[Abstract]:The coupling of chemical reaction and transport process produces complex chemical spatio-temporal dynamics phenomena, such as frontier wave, pulse wave, respiratory wave and Turing structure, etc. The coupling of autocatalytic chemical reaction and diffusion will produce chemical frontier wave. The chemical reactions occurring at the front of the chemical wave and after the wave and the chemical reaction heat generated will bring about changes in solute and temperature in the solution, resulting in changes in the physical quantities of the system, such as density, surface tension, viscosity, etc. Produces a corresponding gradient. The formation of these gradients will lead to different convection, for example, the density gradient will cause the buoyancy convection of the solution as a whole, and the surface tension gradient will cause the Marangoni convection on the liquid-liquid interface of the solution. Chlorite-trisulfate reaction system is a typical exothermic autocatalytic reaction system. Its self-catalyst is hydrogen ion and it is not easy to hydrolyze in alkaline solution. In this paper, the instability of the front wave in the reaction-diffusion-convection of chlorite-trisulfate reaction-diffusion-convection and the surfactant effect in the instability of the front wave are studied by controlling the experimental conditions. In the theoretical study, the coupled multi-physical field equation is used to simulate the instability behavior of the front wave, so as to analyze the dynamic mechanism of the instability. The convection effect of the front wave of the autocatalytic reaction of chlorite-trisulfate autocatalysis on horizontal propagation in a rectangular reactor was investigated. The oscillation propagation of the front wave under the influence of buoyancy convection has been observed for the first time in the experiment. The front wave velocity is related to the concentration of reactant and the height of solution. In the experiment, four surfactants, sodium dodecyl benzene sulfonate, traitone X, thiobetaine 12 and sodium dodecyl sulfate, were introduced to investigate the surfactant effect in front wave instability. When sodium dodecyl benzene sulfonate is added, there are many convective rolls on the front wave, and the change of temperature before and after the front wave is related to its concentration. The thermal effect in the system was weakened by the addition of sodium dodecyl sulfate and the morphology of the front wave showed that the product was under the reactants. In addition to sodium dodecyl sulfate, changes in the concentrations of the other three surfactants affect the velocity and maximum mixing length of the front wave. In addition, in the experiment of adding sodium dodecyl benzene sulfonate, the forward wave velocity is related to the concentration of reactant and the height of solution. In the numerical simulation, the instability behavior of the front wave of the exothermic autocatalytic reaction is simulated by the coupling of the incompressible Navier-Stokes equation, the reaction-diffusion equation and the heat transfer equation. It includes the oscillation propagation of forward wave under buoyancy convection and the instability of forward wave under the coupling of buoyancy convection and Marangoni convection. At the same time, the effects of the temperature coefficient of density in buoyancy convection, the temperature coefficient of surface tension in Marangoni convection and other variables on the instability of front wave are investigated.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O647.2
本文编号：2443621
[Abstract]:The coupling of chemical reaction and transport process produces complex chemical spatio-temporal dynamics phenomena, such as frontier wave, pulse wave, respiratory wave and Turing structure, etc. The coupling of autocatalytic chemical reaction and diffusion will produce chemical frontier wave. The chemical reactions occurring at the front of the chemical wave and after the wave and the chemical reaction heat generated will bring about changes in solute and temperature in the solution, resulting in changes in the physical quantities of the system, such as density, surface tension, viscosity, etc. Produces a corresponding gradient. The formation of these gradients will lead to different convection, for example, the density gradient will cause the buoyancy convection of the solution as a whole, and the surface tension gradient will cause the Marangoni convection on the liquid-liquid interface of the solution. Chlorite-trisulfate reaction system is a typical exothermic autocatalytic reaction system. Its self-catalyst is hydrogen ion and it is not easy to hydrolyze in alkaline solution. In this paper, the instability of the front wave in the reaction-diffusion-convection of chlorite-trisulfate reaction-diffusion-convection and the surfactant effect in the instability of the front wave are studied by controlling the experimental conditions. In the theoretical study, the coupled multi-physical field equation is used to simulate the instability behavior of the front wave, so as to analyze the dynamic mechanism of the instability. The convection effect of the front wave of the autocatalytic reaction of chlorite-trisulfate autocatalysis on horizontal propagation in a rectangular reactor was investigated. The oscillation propagation of the front wave under the influence of buoyancy convection has been observed for the first time in the experiment. The front wave velocity is related to the concentration of reactant and the height of solution. In the experiment, four surfactants, sodium dodecyl benzene sulfonate, traitone X, thiobetaine 12 and sodium dodecyl sulfate, were introduced to investigate the surfactant effect in front wave instability. When sodium dodecyl benzene sulfonate is added, there are many convective rolls on the front wave, and the change of temperature before and after the front wave is related to its concentration. The thermal effect in the system was weakened by the addition of sodium dodecyl sulfate and the morphology of the front wave showed that the product was under the reactants. In addition to sodium dodecyl sulfate, changes in the concentrations of the other three surfactants affect the velocity and maximum mixing length of the front wave. In addition, in the experiment of adding sodium dodecyl benzene sulfonate, the forward wave velocity is related to the concentration of reactant and the height of solution. In the numerical simulation, the instability behavior of the front wave of the exothermic autocatalytic reaction is simulated by the coupling of the incompressible Navier-Stokes equation, the reaction-diffusion equation and the heat transfer equation. It includes the oscillation propagation of forward wave under buoyancy convection and the instability of forward wave under the coupling of buoyancy convection and Marangoni convection. At the same time, the effects of the temperature coefficient of density in buoyancy convection, the temperature coefficient of surface tension in Marangoni convection and other variables on the instability of front wave are investigated.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O647.2
【相似文献】
相关期刊论文 前1条
1 ;化工上的应用[J];生物技术通报;1991年06期
相关硕士学位论文 前1条
1 郑挺;反应扩散对流体系前沿波失稳的表面活性剂效应[D];中国矿业大学;2016年
，本文编号：2443621
本文链接：https://www.wllwen.com/kejilunwen/huaxue/2443621.html
教材专著
