Thermal and Reactive Flow Simulation on High-End Computers

热流和反应流是交叉的基础学科，已在航空航天工程、用于发电和推进的内燃机、地热能、太阳热能、生物能、纳米技术、化学工程和气候科学等技术中得到应用。该领域的研究是高端计算（HEC）可以产生关键影响的主要例子，因为热流和反应流的数值预测和诊断的可靠性和准确性与计算网格分辨率和时间步长的大小直接相关。原因在于存在于热和反应流中的极其宽的时间和长度尺度范围，其通常也是湍流。在具有技术相关性的热流和反应流中存在的最小和最大长度和时间尺度之间有9到12个数量级的变化，理想情况下，应该通过实验测量或数值模拟来解决。如果可能的话，仅仅通过实验来研究这种复杂的现象将是极其昂贵和费力的。另一方面，数值模拟以所需的分辨率和精度提供了所有相关量的非侵入式虚拟“测量”，前提是有足够的计算能力。在过去的二十年里，世界上第一次出现了千兆次浮点运算的超级计算机，然后是万亿次浮点运算，最近是千万亿次浮点运算的机器。最近加快了发展超大规模港灯平台的步伐。就在去年秋天，天河一号A达到了2.566 petaflops的最大持续计算速度，引起了轰动，但六个月后，K计算机达到了惊人的8.162 petaflops。世界上至少有两台20 petaflops的HEC机器正在建造，预计明年投入使用（http：//www.top500.org/）。问题是，超级计算机硬件和软件的进步，尽管看起来令人印象深刻，但几乎跟不上研究需求的步伐。因此，在计算热和反应流的前沿研究往往与利用最新的HEC可用。 我们相信，HEC是热力学和反应流领域前沿研究的关键推动者。该应用程序的主要目的是确保HEC在HECToR及其后继者上的资源，以支持该领域的资助研究项目。这些包括：（a）罗国华（P.I.），EPSRC批准号EP/I 016570/1（09/2011 - 08/2014），“解决低排放能源系统中的燃烧不稳定性：数学建模。数值模拟和控制算法”;（B）K H Luo（P.I.）和R W Eason，EPSRC授权号EP/I012605/1（05/2011 - 05/2014），“Laser-Induced Forward Transfer Nano-Printing Process-Multisale Modeling，Experimental Validation and Optimization”;和（c）N D Sandham（P.I.），正在进行的LAPCAT II EU/FP 7，“长期先进推进概念和技术”。此外，申请人首先开发的广泛使用的SBLI代码将被扩展以包括反应流模拟的能力。通过利用世界级的计算设施HECToR，上述项目将实现产生重要的、世界领先的研究成果的目标。世界首创的模拟实例将包括：（a）湍流预混火焰与声波相互作用的最大直接数值模拟（B）完整激光诱导前向转移过程的格子玻尔兹曼模拟;（c）完整的头到尾超燃冲压喷气发动机的大涡模拟。这些项目与航空航天工程、燃烧、纳米技术、高性能计算等领域的大型研究团体直接相关，将涉及十几家英国和欧盟公司，这将确保研究成果的广泛和及时传播。

Thermal and reactive flows are cross-cutting fundamental disciplines that have found applications in technologies such as aerospace engineering, combustion engines for power generation and propulsion, geothermal energy, solar thermal energy, bioenergy, nanotechnology, chemical engineering and climate science, etc. Research in the field is a prime example where high-end computing (HEC) can have a crucial impact, as the reliability and accuracy of numerical prediction and diagnosis of thermal and reactive flows are directly linked to the computational grid resolution and the size of the time steps. The reason lies with the extremely wide range of time and length scales present in thermal and reactive flows, which are typically turbulent as well. There are 9 to 12 orders of magnitude change between the smallest and the largest length and time scales present in thermal and reactive flows of technical relevance, which should ideally be resolved by experimental measurement or numerical simulation. To study such complex phenomena by experiment alone would be prohibitively expensive and laborious if possible at all. Numerical simulation, on the other hand, offers non-intrusive, virtual "measurement" of all relevant quantities at desired resolution and accuracy, provided sufficient computing power is available. Over the past two decades, the world has first seen gigaflops supercomputers, then teraflops and more recently petaflops machines. The pace of development towards exa-scale HEC platforms has recently quickened. Only last autumn, Tianhe-1A caused a stir by reaching 2.566 petaflops maximum sustained calculation speed, but six months later the K computer achieved an astonishing 8.162 petaflops. At least two HEC machines with 20 petaflops are being built in the world and expected to enter service next year (http://www.top500.org/). The problem is that advance in supercomputing hardware and software, impressive as it appears, has barely kept pace with the research needs. Therefore, frontier research in computational thermal and reactive flows tends to be strongly associated with making use of the latest HEC available. We believe that HEC is a key enabler of cutting-edge research in thermal and reactive flow flows. The main purpose of this application is to secure HEC resources on HECToR and its successors to support funded research projects in the field. These include: (a) K H Luo (P.I.), EPSRC grant No. EP/I016570/1 (09/2011 - 08/2014), "Tackling Combustion Instability in Low-Emission Energy Systems: Mathematical Modelling. Numerical Simulations and Control Algorithms"; (b) K H Luo (P.I.) and R W Eason, EPSRC grant No. EP/I012605/1 (05/2011 - 05/2014), "Laser-Induced Forward Transfer Nano-Printing Process - Multiscale Modelling, Experimental Validation and Optimization"; and (c) N D Sandham (P.I.), on-going LAPCAT II EU/FP7, "Long-term advanced propulsion concepets and technologies". In addition, the widely used SBLI code first developed by the applicants will be extended to incorporate capabilities for reactive flow simulation. By making use of the world-class computing facility HECToR, the above projects will fulfil the objectives of producing significant, world-leading research results. Examples of world-first simulations will include: (a) largest direct numerical simulation of a turbulent premixed flame interacting with acoustic waves (b) lattice Boltzmann simulation of the complete Laser-Induced Forward Transfer (LIFT) process; and (c) large-eddy simulation of a complete nose-to-tail scramjet engine. These projects are of direct interest to large research communities in aerospace engineering, combustion, nanotechnology, high-performance computing and so on, and will involve a dozen UK and EU companies, which will ensure wide and timely dissemination of research results.