共查询到19条相似文献，搜索用时 843 毫秒
1.
为了开发实际适用的富氧燃烧技术，本研究对对向流扩散火焰这一典型的扩散燃烧形态为对象进行实验考查，发现得到的实验结果与作者先前进行的数值模拟结果得到比较好的吻合，即利用详细的基元反应动力学模型对火焰的数值模拟可以很好的再现火焰特性；在此基础上利用CCD成像技术进一步研究了燃料稀释浓度、氧化剂浓度的变化对富氧空气／甲烷对向流扩散火焰形态的影响规律。 相似文献
2.
大气污染扩散模型数值模拟结果的时空多维可视化表达,能有效展示大气污染扩散空间分布,为快速高效辅助后期污染分析与应急决策提供重要的参考。CALPUFF模型能高效模拟污染物在大气环境中时空变化的扩散过程,而现有大气污染扩散模型模拟结果可视化表达普遍存在不能有效集成地理信息、缺失部分重要维度特征等问题。论文首先分析了CALPUFF模型,及其与组件式GIS紧密集成的技术方案,为模型模拟结果与地理信息集成提供了技术支持。然后,基于CALPUFF模型的数值计算模拟结果,详细研究了风场数据预处理及其矢量绘制方法,浓度场的数据预处理及其栅格渲染方法。在三维地形场景下,探究了大气污染物的时空扩散模拟可视化表达方法,给出了CALPUFF模型模拟结果与三维地形场景的集成表达策略。最后,通过组件式GIS,构建了福州市三维地形场景,以大气污染CALPUFF扩散模拟结果为例,在WPF系统框架下,实现了风场和浓度场的时空动态模拟和空间层级多维可视化表达。实验结果表明,本文所采用的时空可视化技术方案能将CALPUFF模型模拟结果,有效集成三维地形场景,实现模型模拟结果在时间维度上动态扩散和在空间维度上的层级分布,可为大气污染模拟结果的时空多维可视化提供参考。 相似文献
3.
近年来，对多金属离子采用同一前处理方法很多，国际法同时测定多种金属离子必须燃烧有机溶剂MIBK，对实验人员有一定的危害，本文利用PAN在不需要引物离子的情况下，对大多数金属离子又能同时引起到捕集和沉淀的性质来浓缩矿泉水中金属离子，用三氯甲烷溶解PAN，硝酸反萃取出PAN中络合的金属离子，火焰原子吸收光谱法测定，结果令人满意，报告如下： 相似文献
4.
文章介绍了富氧空气-乙炔火焰原子吸收法测定锶的方法,讨论了相应实验条件,选择了最优的观测高度、乙炔流量和氧气流量,分析了不同浓度酸对吸光度的影响,方法检出限为0.18μg/m L,该方法快速、简便、准确,适用于测定地质样品中的微量锶。 相似文献
5.
胡正林 《成都信息工程学院学报》1990,(Z1)
本文用数值解扩散方程的方法模拟了长沙市SO_2的浓度分布,并比较了两种扩散系数模型的模拟结果,认为作者曾经给出的扩散系数较取扩散系数为粘性系数时为好。最后提出了一种评价、比较模式的方法 相似文献
6.
蘑菇状火山岩模型的二维地震正演模拟分析 总被引：1，自引：1，他引：0
《东北石油大学学报》2016,(5)
为了研究蘑菇状火山岩储层的地震响应特征,根据地质资料构建蘑菇状火山岩地质模型,分别采用物理模拟和数值模拟方法对蘑菇状火山岩模型进行正演模拟。结果表明,蘑菇状火山岩的地震响应特征总体趋势一致,即火山岩上部外形为蘑菇头状,与其结构形态类似;火山岩下部产生"蘑菇无根"现象,在细节上存在差异。物理模拟方法得到的地震波信息更加丰富,且在模拟过程中地震波的传播方式更符合地下实际情况;数值模拟方法没有噪音干扰,资料品质好,且可以得到波场快照信息。两种正演模拟方法具有互补性,为研究复杂地质情况下的火山岩地震响应特征提供更好的支持。 相似文献
7.
【目的】研究波浪作用下位于水面上方的刚性平板所受冲击力特征,讨论数值计算结果与实验结果的差异。【方法】基于黏性流理论,采用有限体积(VOF)方法建立两相流数值波浪水槽模型,对潜堤地形上波浪传播变形和淹没水平圆柱在波浪作用下受力问题进行数值验证,对平板受波浪冲击作用进行数值模拟,通过平板下表面测点上点压力数值结果特征分析以及与前人实验数据对比,讨论结果差别原因,分析结果特征形成机理。【结果】潜堤地形上波浪传播变形的数值结果和前人实验数据吻合较好;对于波浪作用下平板的受力,相比前人实验数据,冲击力数值结果更大,且呈现出更稳定的周期性特征,沿波浪传播方向平板上的冲击力先增大后减小。【结论】建立的数值模型对波浪与结构物相互作用问题的模拟有高的精确性和稳定性。 相似文献
8.
9.
应用传统的对流扩散方程模拟聚驱后示踪剂产出曲线存在不适应性,将产生质量不守恒或模拟不出实际产出曲线问题.根据连续时间随机游走(CTRW)理论,利用CTRW模型对含聚合物的示踪剂测试实验的产出曲线进行模拟.结果表明:CTRW模型模拟的示踪剂产出曲线克服了基于传统的对流扩散方程模拟示踪剂产出曲线时所遇到的问题;CTRW模型对于模拟聚驱后示踪剂产出曲线具有良好的适应性,比传统的对流扩散方程模拟范围广. 相似文献
10.
城市大气污染扩散GIS模拟分析--以福州市为例 总被引：4，自引：0，他引：4
以福州市为例,分析了GIS在环境模型研究中的主要应用范围;剖析了GIS与环境模型结合的三种层次。在 GIS技术支持下建立了城市点源和线源大气污染扩散模型,采用大气污染扩散模型与GIS的嵌入式的紧密集成技术,进行福州市大气污染扩散模拟,直接采用等值线的方式表达大气污染物在不同气象条件下空间分布模拟结果, 为城市大气污染源的管理和时空模拟提供了一个良好的可视化分析环境。模拟结果表明:2000年福州市区工业路附近区域与福新路附近区域出现SO2高浓度;湖东路、八一七路、福新路、六一北路围成区域出现NOx高浓度,为机动车污染严重的区域。污染物浓度分布与污染源的空间分布和排放量密切相关。 相似文献
11.
LIU Qingzhi HU Yangdong 《中国海洋大学学报(英文版)》2008,7(1):43-47
Using molecular dynamics （MD） simulation, the diffusion of oxygen, methane, ammonia and carbon dioxide in water was simulated in the canonical NVT ensemble, and the diffusion coefficient was analyzed by the clustering method. By comparing to the conventional method （using the Einstein model） and the differentiation-interval variation method, we found that the results obtained by the clustering method used in this study are more close to the experimental values. This method proved to be more reasonable than the other two methods. 相似文献
12.
A finite difference model for solving Navier Stokes equations with turbulence taken into account is used to investigate viscous liquid sloshing-wave interaction with baffles in a tank. The volume-of-fluid and virtual boundary force methods are employed to simulate free surface flow interaction with structures. A liquid sloshing experimental apparatus was established to evaluate the accuracy of the proposed model, as well as to study nonlinear sloshing in a prismatic tank with the baffles. Damping effects of sloshing in a rectangular tank with bottom-mounted vertical baffles and vertical baffles touching the free surface are studied numerically and experimentally. Good agreement is obtained between the present numerical results and experimental data. The numerical results match well with the current experimental data for strong nonlinear sloshing with large free surface slopes. The reduction in sloshing-wave elevation and impact pressure induced by the bottom-mounted vertical baffle and the vertical baffle touching the free surface is estimated by varying the external excitation frequency and the location and height of the vertical baffle under horizontal excitation. 相似文献
13.
Coal bed methane is unconventional raw natural gas stored in coal seam with considerable reserves in China.In recent years,as the coal bed methane production,the safety and the use of resources have been paid more attentions.Evaluating coal bed methane content is an urgent problem.A BET adsorption isotherm equation is used to process the experimental data.The various parameters of BET equation under different temperatures are obtained;a theoretical gas content correction factor is proposed,and an evaluation method of actual coal bed methane is established. 相似文献
14.
By applying experimental and numerical simulations, the motion performance of a semi-submersible platform with mooring positoning
system under combined actions of wind and waves is studied. The numerical simulation is conducted by the method of nonlinear
time domain coupled analysis, and the mooring forces are calculated by the piecewise extrapolating method. The scale in the
model experiment is 1:100, and the mooring system of the model is designed with the method of equivalent water-depth truncation
by comparing the numerical and the experimental results, the platform motion and mooring forces subject to wind and waves
are investigated. The results indicate that the numerically simulated mooring forces agree well with the experimental results
in static equivalent field, but show some difference in dynamic equivalent field; the numerically simulated platform motions
coincide well with the experimental results. The maximum motion of the platform under operating conditions is 20.5 m. It means
that the horizontal displacement is 2% less than the water depth, which satisfies the operating requirements. 相似文献
15.
《中国海洋大学学报(英文版)》2015,(1)
CART(Constituent-oriented age and residence time theory) and PTM(Particle-tracking method) are two widely used numerical methods to calculate water age. These two methods are essentially equivalent in theory but their results may be different in practice. The difference of the two methods was evaluated by applying them to calculate water age in an idealized one-dimensional domain. The model results by the two methods are consistent with each other in the case with either spatially uniform flow field or spatially uniform diffusion coefficient. If we allow the spatial variation in horizontal diffusion, a term called pseudo displacement arising from the spatial variation of diffusion coefficient likely plays an important role for the PTM to obtain accurate water age. In particular, if the water particle is released at a place where the diffusion is not the weakest, the water age calculated by the PTM without pseudo displacement is much larger than that by the CART. This suggests that the pseudo displacement cannot be neglected in the PTM to calculate water age in a realistic ocean. As an example, we present its potential importance in the Bohai Sea where the diffusion coefficient varies spatially and greatly. 相似文献
16.
Ken MacClune 《山地科学学报》2010,7(1):1-14
A high-resolution 2000-year methane record has been constructed from an ice core recovered at 7200 m a.s.l. on the Dasuopu Glacier in the central Himalayas. This sub-tropical methane record reveals an increasing trend in the concentration of methane during the industrial era that is similar to observations from polar regions. However, we also observed the differences in the atmospheric methane mixing ratio between this monsoon record and those from polar regions during pre-industrial times. In the time interval 0-1850 A.D., the average methane concentration in the Dasuopu ice core was 782±40 ppbv and the maximum temporal variation exceeded 200 ppbv. The difference gradient of methane concentration in Dasuopu ice core with Greenland and Antarctica cores are 66±40 ppbv and 107±40 ppbv, respectively. This suggests that the tropical latitudes might have acted as a major global methane source in pre- industrial times. In addition, the temporal fluctuation of the pre-industrial methane records suggests that monsoon evolution incorporated with high methane emission from south Asia might be responsible for the relatively high methane concentration observed in the Dasuopu ice core around A.D. 800 and A.D. 1600. These results provide a rough understanding of the contribution of tropical methane source to the global methane budget and also the relationship between atmospheric methane and climate change. 相似文献
17.
Compared to traditional mode shape identification methods such as eigensystem realization algorithm (ERA), this article proposes a mode shape identification method based on estimated residues of measured data and the theoretical relationship between the estimated residues and the mode shapes from the state space model is obtained by defining a coefficient matrix. A mass-spring model with five degrees of freedom (DOFs) is utilized to demonstrate the approach. The numerical results indicate that the estimated residues are the mode shapes of structures, but with a coefficient matrix to maintain consistency with the mode shapes from the ERA. Using MATLAB a complicated numerical jacket platform is built to further study the proposed method. The results show that mode shapes consistent with those from the ERA could be obtained by taking the defined coefficient matrix into account, which is also demonstrated by a physical beam model that was built at Ocean University of China. 相似文献
18.
Study on the thermal insulation performance of a new seabed sediment fidelity sampler based on ANSYS
A new seabed sediment fidelity sampler was developed and its thermal insulation performance was studied and analyzed. The
temperature distribution simulation indicated that the sample quality could be insured by using this new sampler. Based on
ANSYS10, the temperature finite element model of the sample cylinder was established. According to the law of conservation
of energy, the unsteady heat transmit equation of the sampler under solid-liquid coupling condition was derived, then the
mathematical model calculation was carried out by using a mixed finite-element finite-difference method, and two thermal insulation
methods were used. The simulation was carried out by using the thickness of the thermal insulation layer and heat conductivity
as the variable parameters and the temperature distribution of the sampler and related influencing factors were obtained.
Optimization analysis was conducted using the simulation data and related parameters and the magnitude ranges of the parameters
were obtained that could meet the design temperature requirements. The experimental data and simulation results indicated
that the results were in good agreement with the realities, and this sampler might be of value for seabed sediment sampler
design and manufacture. 相似文献
19.
“重庆雾害”课题组 《成都信息工程学院学报》1992,(2)
本方法从动力、统计相结合的角度出发,利用多年历史资料,采用逐步回归方法并辅以技术处理,求得非线性回归方程为PP模型的预报方程,并且利用正压模式输出的两个月数值预报产品进行了试报,结果表明该模型对重庆雾的24小时预报具有一定的能力。 相似文献