共查询到19条相似文献,搜索用时 156 毫秒
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《工程热物理学报》2021,42(5):1334-1341
针对航空发动机燃烧室等复杂工程中的预混燃烧问题发展高精度、高效的数值预测方法,本研究发展了火焰面生成流型(FGM)详细化学反应建表方法结合超大涡模拟方法(VLES),对工程中的GE LM6000预混旋流燃烧室燃烧开展了高精度数值研究,并与实验结果进行了比较。计算结果表明,VLES-FGM方法可以较准确地预测出旋流预混燃烧室内的流场及温度场分布。为了进一步模拟航空发动机真实的燃烧工况,对原始单头部燃烧室使用周期性边界条件来类比全环燃烧室。计算结果表明,VLES-FGM方法计算得到的周期性燃烧室流场回流区相比较固壁边界燃烧室较小,并且固壁边界燃烧室温度场具有明显的颈部结构,燃烧室下游的高温区分布更为均匀。本文计算结果表明基于FGM燃烧模型的自适应湍流模拟方法VLES对于模拟复杂航空发动机相关的旋流预混燃烧具有很大的应用潜力。 相似文献
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高温空气燃烧炉内湍流混合特性的数值研究 总被引:2,自引:0,他引:2
应用自行研发的三维流动、燃烧、传热和污染物NOx湍流生成的数值模拟程序,对高温空气燃烧实验模型炉进行了湍流扩散燃烧混合特性的数值模拟.数值预报了燃烧室内气体燃料和空气的混合物分数及其湍流脉动的三维分布.数值研究结果表明:在一定的几何条件和气体动力学条件下,高温空气燃烧的湍流混合在更广泛的区域内以较小梯度的进行;混合物分数的脉动主要分布在燃烧区,这表明高温空气燃烧的火焰厚度更大,具有燃烧释热更趋均匀的特性.数值模拟结果与相关的实验结果有相同的规律. 相似文献
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QUICK与多种差分方案的比较和计算 总被引:9,自引:3,他引:6
本文用QUICK和多种差分方案计算了四个流动与换热问题.计算结果表明。对于强制流动问题,QUICK用较粗网格就能得到其他差分方案用较细网格才能得到的结果。对稳态自然对流,QUICK与其他差分方案的计算结果相近,但QUICK方案能预测出所计算的低Pr数流体自然对流的物理振荡,而其他几种方案不能. 相似文献
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A hybrid particle scheme is presented for the simulation of compressible gas flows involving both continuum regions and rarefied regions with strong translational nonequilibrium. The direct simulation Monte Carlo (DSMC) method is applied in rarefied regions, while remaining portions of the flowfield are simulated using a DSMC-based low diffusion particle method for inviscid flow simulation. The hybrid scheme is suitable for either steady state or unsteady flow problems, and can simulate gas mixtures comprising an arbitrary number of species. Numerical procedures are described for strongly coupled two-way information transfer between continuum and rarefied regions, and additional procedures are outlined for the determination of continuum breakdown. The hybrid scheme is evaluated through a comparison with DSMC simulation results for a Mach 6 flow of N2 over a cylinder, and good overall agreement is observed. Large potential efficiency gains (over three orders of magnitude) are estimated for the hybrid algorithm relative to DSMC in a simple example involving a rarefied expansion flow through a small nozzle into a vacuum chamber. 相似文献
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应用隐式SMAC格式计算射流放水阀内部非定常不可压粘性流场 总被引:3,自引:1,他引:2
为了分析射流放水阀内部的非定常不可压粘性流场,在一般曲线坐标系下求解了以逆变速度为参数的不可压N-S方程和压力椭圆方程。计算采用了基于隐式SMAC格式的有限差分格式。在这种格式中,非定常流场的速度是通过使用Crank-Nicholson格式,并在每一时间步处以牛顿迭代的方法得到的;而压力椭圆方程是通过使用Tschebyscheff SLOR格式并交替改变计算方向而求解。通过使用交错网格和迎风差分,诸如改进的QUICK格式;计算过程中的误差和数值不稳定能够得到有效地控制。计算结果和实验观察得到的流动图谱对比表明,二者十分吻合。 相似文献
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本文基于Aspen plus软件对燃用低热值煤气的燃气蒸汽联合循环系统进行了模拟仿真。在该仿真平台上对系统设计工况进行了计算验证。在设计工况下,燃气透平进口温度为1000~1050℃,模拟计算结果为1016.2℃。燃气透平出口温度设计参数为517.2℃,模拟结果为519.2℃。结果表明仿真模型能够准确模拟系统稳态情况的各种工况。本文还运用矩阵模式热经济学的方法对系统设计工况下的(?)流成本进行了计算分析,对系统进行了技术经济评价。燃气轮机和蒸汽轮机电能耗费的能量成本分别为22.2,24.06和16.64$·GJ-1。 相似文献
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Before a hybrid scheme can be developed combining the direct simulation Monte Carlo (DSMC) method and a Navier–Stokes (NS) representation, one must have access to compatible kinetic-split fluxes from the NS portion of the hybrid scheme. The kinetic theory basis is given for the development of the required fluxes from the Chapman–Enskog velocity distribution function for a simple gas; and these are then extended to a polyatomic gas by use of the Eucken approximation. The derived fluxes are then used to implement boundary conditions at solid surfaces that are based on concepts associated with kinetic theory and the DSMC method. This approach is shown to lead to temperature slip and velocity slip as a natural outcome of the new formulation, a requirement for use in the near-continuum regime where DSMC and NS must be joined. Several different flows, for which solid boundaries are not present, are computed using the derived fluxes, together with a second-order finite-volume scheme, and the results are shown to agree well with several established numerical schemes for the NS equations. 相似文献
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渤西油气处理厂天然气凝液回收制冷方案比选研究 总被引:1,自引:0,他引:1
天然气凝液回收的制冷方案是对天然气处理厂的能耗及经济效益有重要影响。文中以中海油拟在天津南港工业区新建的一座油气处理厂为例,通过HYSYS工艺模拟,在不同外输压缩机入口压力条件下,对"膨胀机+DHX制冷工艺"和"膨胀机+丙烷辅助制冷+DHX工艺"两种不同制冷方案进行了对比研究,确定了"膨胀机+丙烷辅助制冷+DHX"、外输压缩机入口压力值为1.4MPa的制冷工艺方案。 相似文献
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N. N. Simakov 《Technical Physics》2017,62(7):1006-1012
A numerical experiment on the simulation of the two-phase flow formed during spraying of a liquid by a nozzle has been described. The radial and axial velocity profiles of the droplets and gas in the free spray and in the two-phase flow through a cylindrical apparatus have been calculated and represented taking into account the early drag crisis of droplets and peculiarities of turbulent friction in the gas, which was detected in previous experiments. The distinguishing feature of the numerical model of the two-phase flow is that it employs the differential equations describing the nonstationary flow of a compressible gas as the initial equations. In transition to their difference analog, the familiar Lax–Wendorff algorithm has been used. A comparison of the results of calculations based on this model with experimental data has demonstrated their concordance. 相似文献
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封闭圆内开缝圆自然对流的非线性特性研究 总被引:2,自引:0,他引:2
本文通过数值计算对封闭圆内开缝圆自然对流的非线性特性进行了研究。数值计算以整个流场为计算区域,采用非稳态数学模型和具有QUICK差分格式的SIMPLE算法。计算结果表明,在不同参数下流动和换热存在稳态定常解、周期性振荡解、拟周期性振荡解和非周期性振荡解。稳态定常解的相图是一个点;周期性振荡解的相图是一个极限环,对应功率谱含一个基频及其谐波;拟周期性振荡解的相图为环面,对应功率谱含两个不相关的频率及它们的线性组合频率;非周期性振荡解的功率谱为无规则的宽带连续谱。 相似文献