窄筛分水洗沙的气测和水测渗透率实验  

EXPERIMENTAL STUDY ON AIR BASED AND WATER BASED PERMEABILITY OF SCREENED WASHED SANDS

作　　者：雷树业[1] 郝锦志[1] 安珍彩[2] 

机构地区：[1]清华大学热能工程系,北京100080 [2]清华大学核能技术研究院,北京100084

出　　处：《工程热物理学报》2006年第z2期105-109,共5页Journal of Engineering Thermophysics

摘　　要：为证实随粒度变细无因次渗透率变大是气测渗透率的特有规律,对粒度100-450μm范围内的五种窄筛分水洗沙的渗透率进行了实验测量对比。实验结果表明,随粒度变细,气测无因次渗透率规律变大是固有的,是流动滑移增强的结果。平均粒度402．5μm筛分沙形成的孔隙尺度不是受流动滑移影响的终结尺度。流动滑移影响远比认定的强,不限于Kn>10-3。同粒度范围内水测渗透率受流动滑移影响不明显,五种筛分沙的无因次渗透率-孔隙率数据几乎都落在曲线K^(1/2)／d=0．283Φ2.67的±4．1％以内。出人预料的是,不受流动滑移的水测渗透率并不比受流动滑移影响的气测渗透率低。平均粒度402．5μm筛分沙的气测渗透率比水测渗透率低近46％,远大于渗透率,孔隙率测量误差之和。数表气体粘度系数包括流动滑移成分,数值偏低是可能的。Under the strict definition of Darcean permeability of the porous media the experimental measurements of the permeability by passing water and atmosphere air through narrow screened washed sands of granularity 100-450μm have been conducted. The experimental results show that for same particle media the air based and water based permeability-porosity relations are different. The water based permeability is proportional to the square of the mean diameter of the particle, most of the experimental data lay around the curve of K^(1/2)/d = 0.283Φ2.67 within±4.1%. The air based permeability is not proportional to the square of the mean particle diameter, as the particles getting finer, the dimensionless permeability is getting larger. The experimental results show that the extraordinary phenomena of the air based permeability just come from velocity slip enhancing as the size of the particles getting finer, and the gas slip effect is not limited in Kn > 10-3, much larger than that recognized. Unexpected fact of the parallel experimental results is that the water based curve K^(1/2)/d -Φis not below all of the air based ones. The water based permeability is higher about 46% than that air based one for same sample sand with granularity 355-450μm though it still affected by slip effect, much larger than possible error in the measurements It is possible that the standard viscosity coefficients of gases in handbooks are not their actual.

关 键 词：多孔介质 渗透率 滑移效应 

分 类 号：TK124[动力工程及工程热物理—工程热物理]