【作者】 刘小平；

【导师】 吴舜英；

【作者基本信息】 华南理工大学 ， 机械设计及理论， 2000， 博士

【摘要】 本文研究在泡沫塑料成型过程中，气泡膨胀阶段的气泡振动机理，阐明气泡振动产生的原因，揭示气泡振动的规律和特性，讨论气泡振动的影响因素及其对气泡振动的作用规律，分析气泡振动对气泡膨胀的影响，寻找控制气泡振动的方法和途径。这一方面在理论上丰富了泡沫塑料成型的气泡膨胀机理，在另一方面对严格控制泡沫塑料成型加工过程，提高泡沫塑料制品的性能等都具有重要的实践指导意义。 在气泡膨胀过程中气液两相共存，气泡膨胀机理复杂，影响因素较多，前人的研究着重单独考虑气泡膨胀体系(BES)的液相而忽视了气相，不能正确反映气泡膨胀过程的气泡振动行为，所以本文对气泡膨胀体系的液相和气相两方面同时进行研究，揭示了气泡膨胀阶段气泡振动的本质和规律。 本文从物理现象上阐明气泡振动产生的原因，对气泡膨胀体系的液相进行研究，引进粘弹本构方程，得到液相控制气泡振动的数学模型即气泡膨胀方程，在数学上线性化气泡膨胀方程，得到线性近似解析解。从此解的数学和物理意义上揭示了线性气泡振动的本质和特性，为验证数值求解结果的正确性和可靠性提供判据。 本文在研究气泡膨胀体系的气相时，把气相作为一个独立的物系，运用气体热动力学理论，研究它的传递行为，建立气泡膨胀体系中气相传递过程的守恒方程组，运用摄动理论处理该方程组，化解了数学求解的难点，最后推导出气泡膨胀体系气相控制气泡振动的数学模型。 联立气泡膨胀体系中气液两相控制气泡振动的数学方程，即构成气泡振动问题的理论求解方程组，然后对方程组进行离散求得数值解。比较数值解与线性近似解析解，发现它们在解释气泡振动的主要特征和规律方面是一致的，近似解析解可以验证数值解的正确性和可靠性，反过来数值解又避免了近似解析解隐盖某些实际物理现象的可能，反映了实际问题的非线性过程。因此将数值计算方法和解析求解方法结合起来，解答复杂的非线性数学问题，是理论分析研究中很值得借签和参考的方法。更多还原

【Abstract】 In this dissertation, the bubble oscillation principle in the bubble expanding process of foam molding was studied. The reason of bubble oscillation was explained, the law and characteristic of bubble oscillation was revealed, the influence factors and their action on bubble oscillation was discussed, the influence of bubble oscillation on bubble expanding was analysed, and the methods controlling bubble oscillation were searched. On the one hand, this enriched bubble expanding principle theoretically. On the other hand, actual guidance was provided for the purpose of strictly controlling foam molding, improving foam part quality etc.As gas and liquid phase coexisted in the process of bubble expand, the principal of bubble expand was complex and influence factors more. In the study of seniors, only studying liquid phase of BES or ignoring gas phase was capable of less correctly reflect bubble oscillation behavior in bubble expand process. So liquid phase and gas phase of BES were researched at the same time in order to reveal nature and law of bubble oscillation in bubble expanding process in the dissertation.In mis dissertation, the reasons of bubble oscillation was explained from physical phenomenon. Liquid phase of bubble expanding system(BES) was studied and viscoelastic constitutive equation was introduced so as to gain mathematical model controlling bubble oscillation of liquid phase i.e. bubble expanding equation. By means of linearizing bubble expanding equation, linear approximate analytic solution was received. From the mathematical and physical meaning of the solution, the nature and property of bubble linear oscillation was showed. This provided a criterion validating the correctness and reliability of numerical solutions.The gfs in a bubble was regarded as a independent substantial system in the dissertation when gas phase investigated. Gas thermodynamics theory was applied to studying the transfer phenomenon of gas phase of BES in order to set up conservation equation groups. We adopted perturbation method to handle the equation groups to disperse mathematical solution difficulty, finally educed mathematical model of更多还原