Mechano-Chemical Interaction in Ultrafast Reactions of Solid Reactants

固体反应物超快反应中的机械-化学相互作用

• 批准号: 9900451
• 负责人: Hendrik Viljoen
• 金额: $ 2.39万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 1999-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9900451&HistoricalAwards=false
• 关键词: Mechano; Chemical; Interaction; Ultrafast; Reactions

Prof. Hendrik J. Viljoen will study heterogenous chemical reactions under mechanic excitation. New macroscopic models will be developed to account for non-equilibrium energy distribution within shock and reaction zones, considering energy distribution among translational, rotation, and vibrational modes, mixing, and supersonic transitions. Molecular dynamics will be used to simulate atomistic behavior in the reaction zone, and distributed continuum dynamics equations will incorporate the atomic model into the macroscopic behavior. These atomistic-macroscopic models may find applications in the description of cryochemical self-propagating reactions; mechanical alloying and sonochemistry as techniques to reduce ignition temperatures and activation energies for reaction; shock-induced reactions of solids, in which chemical reaction energy must be transformed into translational energy in order to sustain the shock wave. The authors will investigate by molecular dynamics the ultrafast reaction between sulfur and aluminum microcrystallites subjected to a shock wave. To develop the continuum model, they will simulate high pressures above the Hugoniot elastic limit, and add equations describing pore collapse and solid compaction to the classical conservation equations. Finally, the molecular dynamics and continuum models will be matched by identifying the critical energy exchange modes and integrating over the characteristic times for the exchange modes. This grant is being funded by the Kinetics and Catalysis and the Process and Reaction Engineering programs.

Hendrik J.Viljoen教授将研究机械激发下的多相化学反应。将开发新的宏观模型来解释激波和反应区内的非平衡能量分布，考虑平移、旋转和振动模式、混合和超音速转变之间的能量分布。分子动力学将被用来模拟反应区的原子行为，而分布式连续介质动力学方程将原子模型纳入宏观行为。这些原子-宏观模型可用于描述低温化学自蔓延反应；机械合金化和声化学作为降低反应的点火温度和活化能的技术；冲击波诱导的固体反应，其中化学反应能量必须转换为平动能以维持冲击波。作者将用分子动力学方法研究冲击波作用下硫与铝微晶之间的超快反应。为了发展连续介质模型，他们将模拟高于Hugoniot弹性极限的高压，并在经典守恒方程中添加描述气孔坍塌和固体压实的方程。最后，分子动力学模型和连续介质模型将通过识别临界能量交换模式并在交换模式的特征时间内积分来匹配。这笔赠款是由动力学和催化以及过程和反应工程项目资助的。