The use of dynamic adaptive chemistry and tabulation in reactive flow simulations
The use of dynamic adaptive chemistry and tabulation in reactive flow simulations
复制标题
DOI：
10.1016/j.combustflame.2013.08.018
复制
发表时间：
2014
影响因子：
4.4
通讯作者：
Zhuyin Ren;Yufeng Liu;T. Lu;L. Lu;O. Oluwole;G. Goldin
中科院分区：
文献类型：
--
作者：
Zhuyin Ren;Yufeng Liu;T. Lu;L. Lu;O. Oluwole;G. Goldin
详细的化学动力学是湍流火焰预测模拟的一个组成部分，对于火焰和排放的可靠预测非常重要。在火焰模拟中引入详细化学的主要挑战是由大量的化学物种和详细动力学所涉及的广泛的时间尺度引起的。在这项工作中，动态自适应化学（DAC）和原位自适应制表（ISAT）的有效化学计算在计算湍流反应流与详细的化学研究异辛烷/空气均质充量压燃（HCCI）和甲烷/空气燃烧在部分搅拌反应器（PaSR）。DAC通过加速控制化学动力学的常微分方程（ODE）与使用有向关系图（DRG）方法实时获得的局部骨架机制的积分来加速化学计算，而ISAT通过列表和重复使用ODE解决方案来减少ODE积分的数量。结果表明，与ISAT相比，DAC的性能主要与燃烧模拟的性质无关，例如，稳定或不稳定，预混或非预混燃烧，其效率随着化学动力学机制的大小而增加。DAC特别适用于包含数百种或更多物质的大型机构的瞬态燃烧模拟，例如汽油或柴油燃料。异辛烷/空气均质压燃燃烧的加速因子约为30，在温度和组分浓度的历史中具有良好的协议。相比之下，ISAT对于化学计算可以主要通过从ISAT表中检索来解决的模拟表现更好，即，重新使用ODE解决方案。结果表明，ISAT实现了约100的加速因子，只有约10%，0.1%和0.01%的NO，CO，和温度，分别引起的误差，为预混甲烷/空气PaSR模拟。此外，耦合DAC和ISAT的方法，即ISAT-DAC，已被开发和证明在这项研究中，以加快化学评价。结果表明，ISAT DAC的温度误差和组分浓度误差得到了很好的控制，当直接ODE积分比例较大时，通过DAC加速ODE积分，可以显著提高ISAT的性能.
Detailed chemical kinetics is an integral component for predictive simulation of turbulent flames and is important for reliable prediction of flames and emissions. Major challenges of incorporation of detailed chemistry in flame simulations are induced by the large number of chemical species and the wide range of timescales involved in detailed kinetics. In this work, dynamic adaptive chemistry (DAC) and in situ adaptive tabulation (ISAT) for efficient chemistry calculations in calculating turbulent reactive flows with detailed chemistry are studied in iso-octane/air homogeneous charge compression ignition (HCCI) and methane/air combustion in a partially-stirred reactor (PaSR). Chemistry calculations are accelerated by DAC via expediting the integration of ordinary differential equations (ODEs) governing chemical kinetics with local skeletal mechanisms obtained on-the-fly using the directed relation graph (DRG) method, and by ISAT via reducing the number of ODE integrations through tabulating and re-using the ODE solutions. It is shown that, in contrast to ISAT, the performance of DAC is mostly independent of the nature of combustion simulations, e.g., steady or unsteady, premixed or non-premixed combustion, and its efficiency increases with the size of chemical kinetic mechanisms. DAC is particularly suitable for transient combustion simulations with large mechanisms containing hundreds of species or more, such as those for gasoline or diesel fuels. A speedup factor of about 30 is achieved for HCCI combustion of iso-octane/air with good agreements in the histories of temperature and species concentrations. In contrast, ISAT performs better for simulations where chemistry calculations can be predominantly resolved by retrieving from the ISAT table, i.e., re-using the ODE solutions. It is shown that ISAT achieves speedup factors of about 100 with only about 10%, 0.1% and 0.01% incurred errors in NO, CO, and temperature, respectively, for the premixed methane/air PaSR simulations. Moreover, a coupled DAC and ISAT approach, namely ISAT–DAC, has been developed and demonstrated in this study to accelerate chemistry evaluation. It is shown that the incurred errors in temperature and species concentrations in ISAT–DAC are well controlled, and it can significantly enhance the performance of ISAT, when the fraction of direct ODE integration is significant, via accelerating the ODE integrations by DAC.