微灌砂过滤器石英砂滤料颗粒粗糙度参数测算与分析

微灌砂过滤器砂滤料颗粒的表面粗糙度直接影响到砂滤层水头损失和对水中杂质的滞纳能力,从而影响到滤层过滤效果。为了对砂滤料颗粒表面粗糙度进行定量分析,以粒径范围为1.0~1.18、1.18~1.4和1.4~1.7 mm的3种滤料的砂滤料颗粒为研究对象,每种滤料选取15粒石英砂作为样本,以砂滤料颗粒表面形貌的均方根偏差、表面高度分布的偏斜度和表面高度分布的峭度表征颗粒表面粗糙度,采用三维表面形貌仪对粗糙度参数进行测量,采用统计分析方法对粗糙度参数进行分析。结果表明,3种滤料砂滤料颗粒表面波峰波谷的波动幅度分别占滤料当量粒径的15.6%、14.6%和13.1%,说明微灌砂过滤器砂滤料颗粒表面粗糙度比较大;石英砂滤料颗粒表面高度分布的峭度比较大,说明砂滤料颗粒表面形貌高度分布比较集中;石英砂滤料颗粒表面高度分布的偏斜度都为负,说明砂滤料颗粒表面凹陷部分所占比例偏大,影响过滤效果。通过研究认为,要使过滤器石英砂滤料获得更好的过滤效果,应选取相对较大颗粒的石英砂滤料,并对砂滤料的生产工艺进行改进,使砂滤料粗糙度适当增大。

Measurement and Analysis of Roughness Parameters of Quartz Sand Particles for Sand filters in Micro-Irrigation

The surface roughness of sand particles in micro-irrigation directly affects the waterhead loss of sand filter layer and the ability of holding impurity particles in raw water,and thus affects the filtering effect of the filter layer.In order to quantitatively analyze the surface roughness of sand particles,three kinds of quartz sand filter layer with the diameter range 1.0~1.18,1.18~1.4 and 1.4~1.7 mm respectively are studied as research objects.Fifteen quartz sand samples are selected as samples for each filter layer.The surface roughness of sand particles is characterized by root mean square height of surface morphology,skewness of surface height distribution and kurtosis of surface height distribution.The roughness parameters are measured by three-dimensional surface topography instrument.And the roughness parametersare analyzed by statistical analysis method.The results show that the fluctuation ranges of surface wave crest and trough of the three kinds of sand particles accounts for 15.6%,,14.6%and 13.1%of the equivalent particle size of the particles respectively,and indicate that the surface roughness of sand particles is relatively large.And the kurtosis of the surface height distribution of quartz sand particles is relatively large also,which indicatethat the surface topography of sand particles is relatively concentrated.At the same time,the skewness of the height distribution on the surface of quartz sand particles is negative, which indicates that the proportion of sags on the surface of quartz sand particles is larger. In order to make quartz filter materials more suitable for micro-irrigation system, larger grains of quartz filter materials should be selected, and the process of sand filter materials should be improved, so that the roughness of sand filter materials can be increased appropriately.