共查询到18条相似文献,搜索用时 203 毫秒
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泵站水泵进水池内防涡装置有效性的数值验证 总被引:4,自引:0,他引:4
本文提出了一种消除泵站水泵吸水管内旋涡和流动分离的圆锥形防涡装置。为了验证该装置的有效性,建立了泵站水泵进水池和吸水管内三维湍流流场的数学模型,用分区网格构造了泵站水泵进水池和吸水管的贴体计算网格,采用有限体积方法,计算了无圆锥形防涡装置和有圆锥形防涡装置时,水泵进水池和吸水管内三维湍流流场,结果证明该圆锥形防涡装置能有效消除水泵吸水管内旋涡和流动分离。 相似文献
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水泵吸水池内部的流动情况非常复杂,尤其是在吸入管的附近存在着很强的漩涡,这些漩涡使得流动的非定常特性非常强烈,本文用小波分析的方法来处理一种开敞式水泵吸水池内流动的非定常信号,它们分别是压力信号,振动信号和声音信号。在处理的过程中,应用离散小波变换,将不同时间和空间尺度下的信号进行分解,分别得到分解后的小波系数,再将不同层次的信号进行重构,并对各个层次的分解信号进行功率谱分析,得到这些非定常信号的分布规律。 相似文献
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针对压裂过程中出现的不对称垂直裂缝问题,基于渗流力学原理,根据点源函数和Green函数基本理论建立三种不同外边界条件下不对称有限导流垂直裂缝试井解释数学模型.采用Laplace积分变换和Stehfest数值反演获得典型特征曲线.研究表明:典型特征曲线分为四个流动阶段,井储阶段、压力导数曲线斜率为1/4的双线性流阶段、压力导数曲线斜率为1/2的线性流阶段及0.5水平线的径向流阶段;不对称因子主要影响双线性流阶段结束的时间,不对称因子越大,双线性流阶段结束的越早;裂缝的导流能力越大,不对称因子对特征曲线的影响越不明显;不对称因子越大,裂缝流量分布越不对称.为不对称有限导流垂直裂缝的试井分析提供理论依据. 相似文献
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《工程热物理学报》2021,42(9):2419-2430
通过毛细对流可视化实验系统和三维数值模拟研究了旋转环形液池内受Soret效应影响的双组分溶液热毛细对流,探究了泰勒数和液池深宽比对双组分溶液热毛细对流的稳定性及失稳后产生的振荡流型的影响。结果表明,旋转液池内受Soret效应影响的热毛细对流的基础流为逆时针流胞形成的轴对称稳态流动,液池旋转对基础流径向流动的影响较小,但会明显增大流体的相对周向流动。临界热毛细雷诺数随泰勒数的增大而增大,随深宽比的增大而减小。泰勒数和深宽比的变化会明显改变双组分溶液热毛细对流失稳后产生的振荡流型。随着泰勒数的增大,液池中会出现HTWs和内部波动共存的振荡流型,内部振荡由包含在基态流动中的旋转流胞产生。 相似文献
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Analysis of Two-Phase Cavitating Flow with Two-Fluid Model Using Integrated Boltzmann Equations 下载免费PDF全文
Shuhong Liu Yulin Wu Yu Xu & Hua-Shu Dou 《advances in applied mathematics and mechanics.》2013,5(5):607-638
In the present work, both computational and experimental methods are employed
to study the two-phase flow occurring in a model pump sump. The two-fluid
model of the two-phase flow has been applied to the simulation of the three-dimensional
cavitating flow. The governing equations of the two-phase cavitating flow
are derived from the kinetic theory based on the Boltzmann equation. The isotropic
RNG$k-\epsilon-k_{ca}$ turbulence model of two-phase flows in the form of cavity number instead
of the form of cavity phase volume fraction is developed. The RNG $k-\epsilon-k_{ca}$ turbulence
model, that is the RNG$k-\epsilon$ turbulence model for the liquid phase combined
with the $k_{ca}$model for the cavity phase, is employed to close the governing turbulent
equations of the two-phase flow. The computation of the cavitating flow through a
model pump sump has been carried out with this model in three-dimensional spaces.
The calculated results have been compared with the data of the PIV experiment. Good
qualitative agreement has been achieved which exhibits the reliability of the numerical
simulation model. 相似文献
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实验研究了低频交变电磁场作用下, 7075合金半连铸坯微观组织形貌及各溶质元素的固溶 情况;并就电磁场对液固相线位置和结晶间隔的改变进行了测定;此外还数值模拟了电磁场 对半连铸过程中液穴内部温度场和流动场的影响.从电磁场对7075合金凝固过程中的溶质分 配系数,结晶间隔,液穴内部温度场、流动场以及微观组织形貌的影响出发,尝试性地对电 磁场的强制固溶机理进行探讨性的解释和说明.
关键词:
电磁场
半连铸
铝合金
固溶 相似文献
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B. Wellegehausen L. Laepple H. Welling 《Applied Physics A: Materials Science & Processing》1975,6(3):335-340
The dependance of the output power of cw dye lasers on the pump power and the system-and stream parameters is calculated and experimentally tested. It was found that the pump power for a given system is limited to a critical value due to the influence of thermal inhomogeneities. This critical pump power is predominantly dependant on the dye solvent, the flow velocity, the focussing of the pump laser and the stability range of the dye laser system. Possibilities for the reduction of the thermal inhomogeneities are discussed and attainable output powers are calculated. 相似文献