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81.
雷诺方程的数值计算方法概述 总被引:1,自引:0,他引:1
作为流体力学中的基本公式,雷诺方程的数值求解一直是流体润滑领域研究的重要方向之一。以雷诺方程的基本形式为基础,分别介绍有限差分法、有限元法和有限体积法求解雷诺方程的过程,讨论各自的特点及存在的问题;介绍多重网格法同上述方法结合在求解雷诺方程中的应用,指出多重网格法在求解雷诺方程的高效性方面有了很大程度的突破,但在求解精度上并未有显著改善;讨论等几何分析方法在求解雷诺方程上的应用,指出等几何分析方法求解雷诺方程具有较高的效率和求解精度,但仍存在如样条基函数的不可插值性和IGA在雷诺方程求解方面的普适性等问题,探讨IGA的研究方向,如针对特定雷诺方程引入适于IGA的新型样条表征求解空间、修改IGA理论与雷诺方程的离散模式引入新型边界条件加载模式等;因数值求解雷诺方程时在边界处理、复杂求解域等问题上仍没有一个稳定适用面广的方法,建议可尝试联合IGA与多重网格法来求解雷诺方程,以进一步提高求解效率和精度。 相似文献
82.
Flow and heat transfer analysis of an electrically conducting MHD power law nano fluid is carried out through annular sector duct,under the influence of constant pressure gradient.Two types of nano particles(i.e.Cu and TiO2)are used in power law nano fluid.Strongly implicit procedure,(SIP)is used to simulate the discretized coupled algebraic equations.It has been observed that volume fraction of nano particles,ϕand magnetic field parameter,Ha are favourable for the heat transfer rate,however,both resist the fluid flow.Impact of applied uniform transverse magnetic field exceeds in the case of shear thickening fluids(i.e.n>1)by increasing the value of Ha as compared to that in shear thinning fluids(i.e.n<1).Therefore,enhancement in heat transfer rate is comparably more in shear thickening fluid.Furthermore,comparable limiting case study with published result is also carried out in this research paper. 相似文献
83.
The present work focuses on a two‐dimensional steady incompressible stagnation point flow of a Jeffery fluid over a stretching sheet. The Cattaneo‐Christov heat flux model is incorporated into this study. Simulation is conducted via the Runge‐Kutta fourth‐order cum shooting method for the transformed system of nonlinear equations. The influence of the governing parameters on the dimensionless velocity, temperature, skin friction, streamlines, and isotherms is incorporated. A significant outcome of the current investigation is that an increase in the relaxation time parameter uplifts temperature; however, a gradual decrease is observed in the velocity field. Another important outcome of the present analysis is that the momentum boundary layer augments due to an increase in the Deborah number; however, a decrease is observed in the temperature. Furthermore, it is also observed that the skin friction coefficient escalates with an increase in the relaxation time parameter for the assisting flow, but a reverse trend is observed for the opposing flow. 相似文献
84.
85.
通过盐雾试验模拟潮湿环境,对裸钢试片、电镀锌钢试片、化学镀镍-磷钢试片和化学镀镍-钴-磷钢试片进行了宏观形貌、微观形貌和腐蚀产物成分分析,比较了四个试片的耐盐雾腐蚀性能。结果表明:在盐雾环境中,四个试片均会发生电化学腐蚀,生成不同的腐蚀产物;在盐雾腐蚀周期内,裸钢试片的腐蚀速率最高,化学镀镍-磷钢试片和化学镀镍-钴-磷钢试片的腐蚀速率较低;四个试片在腐蚀过程中的阳极反应和阴极反应不同,腐蚀后的微观形貌存在明显差异。 相似文献
86.
湖南省郴州市饭垄堆北段锡钨多金属矿位于湘南钨锡钼铋多金属成矿带东坡矿田内,成矿地质条件优越,具有很好的找矿前景。根据该矿床地质特征以及已有的地质矿产勘查成果,系统总结了矿区101、102、103号主矿体特征。在此基础上,进一步讨论了该类裂隙充填细脉带型锡钨多金属矿床在勘查过程中探矿工程布置的优化方法:即:①探矿工程不宜按每个矿带单独控制,应对整个赋矿层位进行整体控制;②应对含有毒砂、锡、钨细脉的岩性段进行连续取样化验,既可避免漏矿,又可以为将来工业指标调整后重新圈定矿体提供直接依据。 相似文献
87.
88.
《International Journal of Hydrogen Energy》2020,45(7):4174-4181
The concept of thermochemical exhaust heat recuperation by steam reforming of biofuels is considered. Thermochemical recuperation can be considered as an on-board hydrogen production technology. A schematic diagram of a fuel-consuming equipment with thermochemical heat recuperation is described. The thermodynamic analysis of the thermochemical recuperation systems was performed to determine the efficiency of using various fuels, in particular, methanol, ethanol, n-butanol, and glycerol. The thermodynamic analysis was performed by Gibbs free energy minimization method and implemented using the Aspen Hysys program. The thermodynamic analysis was performed for a wide temperature range from 400 to 900 K, for steam-to-fuel of 1, and pressures of 1 bar. The maximum fuel conversion reaches for the following temperatures: methanol - 600 K, ethanol - 730 K, n-butanol - 860 K, glycerol - 890 K. The dependence of the reforming enthalpy on temperature is determined. It was shown that the reaction enthalpy determines the heat transformation coefficient, which shows the ratio of the low heat value of synthetic fuel and the low heat value of the initial fuel. For all studied fuels, the maximum value of the transformation coefficient is observed for steam reforming of ethanol and the maximum heat transformation coefficient is 1.187. The temperature range is determined at which the maximum efficiency of the use of thermochemical recuperation occurs due to the reforming of biofuels. For methanol, the effective temperature is about 600 K, for ethanol is about 700 K, for n-butanol is 850 K, for glycerol is more than 900 K. The results obtained make it possible to efficiently select the type of fuel for thermochemical recuperation due to steam reforming. 相似文献
89.
福建某斑岩型金矿品位低、规模大,金主要以自然金形式存在,可见金的粒度较粗,为高效利用该低品位金矿,开展新型浸金剂金蝉全泥浸出试验和柱浸试验,结果表明:全泥浸出在磨矿细度为-0.074 mm占80%、矿浆浓度25%、加石灰调pH 值11.0左右、初始金蝉浓度为500 mg/L和过程中控制金蝉浓度不小于300 mg/L条件下浸出20 h,金的浸出率为93.43%,金蝉耗量为1.02 kg/t;柱浸在矿石粒度为-30 mm条件下喷淋浸出23天,金累计浸出率和金蝉累计耗量分别为86.54%和1.22 kg/t。 相似文献
90.
Jonas Maximilian Müller Nicolas Rozo Lopez Enzo Alexander Klein Christian Hopmann 《Polymer Engineering and Science》2020,60(6):1324-1332
For fiber-reinforced plastics, the strain-rate dependent response is governed by the matrix behavior. In this work, the Goldberg model is considered for the epoxy matrix constitutive material model. Moreover, the strain-rate dependency is achieved by direct influence on the elastic modulus, the inelastic strain, and the material strain to failure. In addition, an anisotropic damage response is implemented and extended through a strain-rate dependent definition. Since the constitutive model relies on nonphysical parameters, a parameter study is further performed. Additional numerical investigations using a micro-mechanical model are performed. Tension and shear loading conditions are evaluated and the influence of different strain rates is explored. Furthermore, the implemented anisotropic damage model is compared and discussed against an isotropic damage model. 相似文献