【摘要】：化學(xué)反應(yīng)和輸運過程的耦合產(chǎn)生復(fù)雜的化學(xué)時空動力學(xué)現(xiàn)象,如前沿波、脈沖波、呼吸波和圖靈結(jié)構(gòu)等。自催化化學(xué)反應(yīng)與擴散的耦合,將產(chǎn)生化學(xué)前沿波。在化學(xué)波的前沿和波后發(fā)生的化學(xué)反應(yīng)和產(chǎn)生的化學(xué)反應(yīng)熱,將帶來溶液中溶質(zhì)變化和溫度變化,使得系統(tǒng)中的物理量,如密度、表面張力、粘度等發(fā)生變化,產(chǎn)生相應(yīng)的梯度。這些梯度的產(chǎn)生會引入不同的對流,例如,密度梯度將引起溶液整體的浮力對流,而表面張力梯度將引起溶液氣液界面上Marangoni對流。亞氯酸鹽-連三硫酸鹽反應(yīng)體系是典型的放熱自催化反應(yīng)體系,其自催化劑是氫離子,且連三硫酸鹽在堿性溶液中不易水解。本文通過控制實驗條件,深入研究了亞氯酸鹽-連三硫酸鹽反應(yīng)-擴散-對流前沿波的失穩(wěn)現(xiàn)象,以及在前沿波失穩(wěn)中的表面活性劑效應(yīng)。在理論研究中,使用耦合的多物理場方程模擬前沿波失穩(wěn)行為,從而分析失穩(wěn)產(chǎn)生的動力學(xué)機理。實驗探究了亞氯酸鹽-連三硫酸鹽放熱自催化反應(yīng)前沿波在長方體型反應(yīng)器中水平傳播時受到的對流影響。首次在實驗中觀察到前沿波在浮力對流影響下的振蕩傳播。并且前沿波速度與反應(yīng)物濃度和溶液高度有關(guān)。實驗中通過引入四種表面活性劑,分別是十二烷基苯磺酸鈉、曲拉通X-100、硫代甜菜堿12和十二烷基硫酸鈉,探究了前沿波失穩(wěn)中的表面活性劑效應(yīng)。當加入十二烷基苯磺酸鈉時,前沿波上出現(xiàn)多對流卷,并且前沿波前后的溫度變化與其濃度有關(guān)。而十二烷基硫酸鈉的加入使得體系中的熱效應(yīng)減弱,前沿波的形態(tài)表現(xiàn)為產(chǎn)物在反應(yīng)物下方。除了十二烷基硫酸鈉,其他三種表面活性劑濃度的變化會對前沿波的速度和最大混合長度產(chǎn)生影響。并且,在加入十二烷基苯磺酸鈉的實驗中,前沿波波速與反應(yīng)物濃度和溶液高度有關(guān)。在數(shù)值模擬中,利用不可壓縮的Navier-Stokes方程、反應(yīng)-擴散方程和傳熱方程三者的耦合,模擬了放熱自催化反應(yīng)前沿波在對流影響下的失穩(wěn)行為,包括浮力對流主導(dǎo)下的前沿波振蕩傳播,以及浮力對流和Marangoni對流耦合作用下的前沿波失穩(wěn)。同時,考察了浮力對流中密度溫度系數(shù),Marangoni對流中表面張力溫度系數(shù)及其他變量對前沿波失穩(wěn)的影響。
[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.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：O647.2

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本文編號：2443621