• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Physical models and computational algorithms for simulation of full-scale catalytic monolithic reactors.
【24h】

Physical models and computational algorithms for simulation of full-scale catalytic monolithic reactors.

机译：用于模拟大型催化整体反应器的物理模型和计算算法。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The focus of this thesis is the development of physical models and computational algorithms for the modeling of full-scale catalytic monolithic reactors. Surface reaction is the cornerstone of the operation of such devices, and diffusion is the only mode, locally, by which reactants are transported to the reacting surfaces. In the first part of the study, detailed numerical studies are performed for a representative channel of a typical monolithic reactor to explore the impact of different diffusion models on the simulation results. An optimum diffusion model, henceforth referred to as the Schmidt Number model, is identified for modeling of catalytic reactor operations, based on both accuracy as well as computational efficiency standpoints.;In the second part of the thesis, a new low-memory solver for implicit coupled solution of the species conservation equations is developed. This solver, henceforth known as the IDD+GMRES solver, significantly enhances the stability and convergence of steady state CFD simulations, in comparison to the widely used segregated solution approach. The efficacy of this method is demonstrated using various test cases ranging from pure multi-component diffusion, homogenous combustion of hydrocarbons (laminar flames) and catalytic combustion in both two-dimensional and complex three-dimensional geometries. Use of the IDD+GMRES solver leads to up to 2.5 times reduction in overall computational time and up to 5 times reduction in the time taken by the solution of the species conservation equations, as compared to point implicit Block-Gauss Siedel solvers.;In the third part of the thesis, acceleration of surface chemistry calculation is performed by adapting the In Situ Adaptive Tabulation (ISAT) algorithm for heterogeneous reactions. The ISAT algorithm for surface chemistry is developed from ground up and linked with the CFD code developed in the second part of the thesis. The use of the new ISAT algorithm is demonstrated for channel-scale modeling of catalytic combustion and three-way catalytic conversion and for a full-scale monolithic reactor model of catalytic combustion application. The use of the ISAT algorithm leads to an additional reduction in overall computational time between 50 percent and 150 percent for the cases studied, while speeding-up the surface chemistry calculations alone by up to 11 times.;In the final step, developments resulting from both physical modeling studies and computational algorithm studies are integrated to perform modeling of full-scale monolithic reactors with complex chemistry.;Key contributions of this thesis include investigation and identification of a diffusion model for catalytic monolithic reactor calculations, development of a new low-memory coupled implicit solver for the species conservation equations, the first reported study of the adaptation and use of the ISAT algorithm for large-scale CFD calculations with complex surface chemistry, and integration of all of the above models/algorithms into a single simulation tool for the simulation of full-scale catalytic monolithic reactors.
机译：本文的重点是物理模型和计算算法的发展，用于大规模催化整体反应器的建模。表面反应是这种装置运行的基石，扩散是局部地将反应物输送到反应表面的唯一方式。在研究的第一部分中，对典型的整体反应器的代表性通道进行了详细的数值研究，以探索不同扩散模型对模拟结果的影响。基于精度和计算效率的观点，确定了用于催化反应器运行建模的最佳扩散模型（以下称为Schmidt数模型）。在本文的第二部分，一种新型的低内存求解器建立了物种守恒方程的隐式耦合解。与广泛使用的分离求解方法相比，此求解器（以下称为IDD + GMRES求解器）显着提高了稳态CFD仿真的稳定性和收敛性。该方法的有效性在各种测试案例中得到了证明，包括纯二维多组分扩散，碳氢化合物的均匀燃烧（层状火焰）以及二维和复杂三维几何形状中的催化燃烧。与点隐式块高斯Siedel求解器相比，使用IDD + GMRES求解器可将总体计算时间减少多达2.5倍，并将物种守恒方程的求解时间减少多达5倍。第三部分，通过针对异质反应采用原位自适应制表法（ISAT），加快了表面化学计算的速度。表面化学的ISAT算法是从头开始开发的，并与论文第二部分中开发的CFD代码相联系。演示了使用新的ISAT算法进行催化燃烧和三效催化转化的通道规模建模以及催化燃烧应用的全尺寸整体反应器模型的过程。对于所研究的案例，使用ISAT算法可将总体计算时间进一步减少50％至150％，同时将表面化学计算的速度提高多达11倍。物理模型研究和计算算法研究相结合，以进行具有复杂化学反应的全尺寸整体式反应器的建模。本论文的主要贡献包括研究和识别用于催化整体式反应器计算的扩散模型，开发新的低内存量耦合的隐式求解器用于物种守恒方程式，首次报道了ISAT算法在具有复杂表面化学性质的大规模CFD计算中的适应性和使用，并将上述所有模型/算法集成到单个模拟工具中大规模催化整体反应器的模拟

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号