• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Combustion and Flame >A systematic approach to high-fidelity modeling and efficient simulation of supercritical fluid mixing and combustion
【24h】

A systematic approach to high-fidelity modeling and efficient simulation of supercritical fluid mixing and combustion

机译：一种高保真建模和超临界流体混合与燃烧的高效仿真的系统方法

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

Advances in fluid-flow modeling and simulation techniques over the past two decades have improved understanding of the intricate flow physics and combustion dynamics in the supercritical regime. However, there remain many numerical issues to be addressed, including turbulence closure modeling, combustion modeling, and the evaluation of real-fluid thermodynamic and transport properties. The challenges can be broadly categorized into two areas: (1) achieving highly accurate simulation through inclusion of all the necessary physics and (2) developing a computationally efficient framework to achieve simulation results in a reasonable turnaround time. This paper investigates these challenges and presents a systematic approach to achieve high-fidelity and efficient simulation of supercritical fluid mixing and combustion using large-eddy simulation (LES) techniques. The unresolved subgrid-scale (SGS) term in the filtered equation of state (EOS), which is generally neglected for ideal gases, becomes significant for real fluids, especially in regions of strong property gradients at supercritical conditions. The relative error for the filtered density can reach up to 40%, and this uncertainty can propagate and contaminate calculations of the conservation equations. Two closure models for the SGS term in the EOS are proposed: a gradient-based and a mixing-based approach. Both approaches reduce the modeling error considerably. Flamelet-based combustion models are also examined at supercritical conditions. The probability density functions (PDFs) for mixture fraction and scalar dissipation rate are evaluated using a data-driven approach. The presumed beta-function distribution accurately describes the PDF of the mixture fraction at low mixture fraction variance, but deviates at high variance (> 0.01). The lognormal distribution can capture the shape of the extracted PDF of the scalar dissipation rate but underestimates the peak value. An alternative combustion model using finite-rate chemistry integrated with dynamic adaptive chemistry and correlated transport is developed, rendering a computationally efficient and affordable framework. The efficiency of evaluating real-fluid thermodynamic and transport properties, a computationally expensive procedure, is dramatically enhanced using tabulation and correlated dynamic evaluation techniques. Finally, suggestions are provided regarding opportunities for future research.
机译：在过去的二十年中，流体流动建模和模拟技术的进步使人们对超临界状态下复杂的流动物理学和燃烧动力学有了更深入的了解。但是，仍然有许多数值问题需要解决，包括湍流闭合模型，燃烧模型以及实际流体热力学和传输特性的评估。挑战可大致分为两个领域：（1）通过包含所有必要的物理学来实现高度精确的仿真；（2）开发计算效率高的框架，以在合理的周转时间内获得仿真结果。本文研究了这些挑战，并提出了使用大涡流仿真（LES）技术实现超临界流体混合和燃烧的高保真高效仿真的系统方法。过滤状态方程（EOS）中的未解析子网格规模（SGS）项（通常对于理想气体而言通常被忽略）对于实际流体变得尤为重要，尤其是在超临界条件下具有强特性梯度的区域。滤波后的密度的相对误差可高达40％，并且这种不确定性会传播并污染守恒方程式的计算。针对EOS中的SGS术语，提出了两种封闭模型：基于梯度的方法和基于混合的方法。两种方法都大大降低了建模误差。还基于火焰的燃烧模型在超临界条件下进行了检查。使用数据驱动的方法评估混合分数和标量耗散率的概率密度函数（PDF）。假定的β函数分布在低混合分数方差下准确地描述了混合分数的PDF，但在高方差下（> 0.01）有偏差。对数正态分布可以捕获标量耗散率的提取PDF的形状，但低估了峰值。开发了一种将有限速率化学与动态自适应化学及相关运输相结合的替代燃烧模型，从而提供了一种计算有效且价格合理的框架。使用制表和相关的动态评估技术，显着提高了评估实际流体热力学和传输特性的效率，这是一种计算量巨大的程序。最后，提供了有关未来研究机会的建议。

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