不同加气和粒径条件下浑水滴灌滴头堵塞特性研究

Clogging Characteristics of Muddy Drip Irrigation Dripper under Different Aeration and Particle Size Conditions

摘要:

为探明浑水滴灌过程中水中加气对滴头堵塞的影响，以齿形迷宫流道滴头为研究对象，采用周期性间歇灌水测试方法，用最大粒径小于0.1mm的泥沙配置了5种不同的浑水，运用激光粒度分析仪和场发射扫描电镜等方法研究了滴头堵塞状况。结果表明：加气和泥沙颗粒级配对滴头堵塞具有极显著影响（P<0.01)；加气提升了毛管内泥沙输移能力、促进大泥沙颗粒排出，减小淤积泥沙中值粒径，且泥沙最大粒径越小，加气对泥沙运移的影响越小，毛管淤积物质量、淤积泥沙中值粒径较未加气处理减少8.75%～31.92%、8.59%～35.64%；泥沙粒径为0.075～0.100mm时，滴头流量下降最快，泥沙为粒径0～0100mm时，滴头流量下降最慢；加气增大了水流紊动程度，促进浑水中大颗粒泥沙在流道内的输移；加气加剧了浑水中小颗粒泥沙在流道入口处黏附，加速了流道入口堵塞，滴头Dra和Cu比未加气处理低9.0～18.7个百分点和16.2～36.4个百分点，这是造成加气加速滴头堵塞的主要原因。建议进行毛管冲洗，降低流道入口堵塞风险，以提高加气滴灌滴头的抗堵塞性。

关键词:滴灌;迷宫流道;加气;泥沙粒径;堵塞

Abstract:

Underground drip irrigation is the best way of aerated irrigation, but the narrow channel of the dripper is easy to be clogged by particles in the water. It is of great significance to improve the operation efficiency of aerated drip irrigation system if the law of fine sediment transport and deposition under aerated conditions can be found out and reasonable control measures can be taken to alleviate dripper clogging. In order to explore the influence of aeration on the dripper clogging, five kinds of sediment graded muddy water (0～0.100mm, 0.075~0.100mm, 0.050~0.075mm, 0.031~0.050mm and 0～0.031mm) with sediment concentration of 1g/L were disposed and the effect of aeration in water on the toothed labyrinth channel dripper clogging was studied by periodic intermittent irrigation test. The deposited sediment was observed and analyzed by laser particle size analyzer and field emission scanning electron microscope. The results showed that aeration and sediment particle size had significant effect on dripper clogging (P<0.01). Aeration improved the sediment transport capability in the laterals, promoted the discharge of large particle sediment, reduced the median particle size of depositing sediment and the effect of aeration on sediment transport was decreased with the decrease of the maximum particle size of sediment. The mass of depositing sediment and the median particle size of depositing sediment in the laterals were 8.75%～31.92% and 8.59%～35.64% lower than those without aerated treatment. When the particle size was 0.075~0.100mm, the relative flow rate of the dripper was decreased the fastest and the relative flow rate of the dripper was decreased the slowest when the particle size was 0～0.100mm. Aeration enhanced the degree of flow turbulence and promoted the transport of large-particle sediment in the flow channel. Aeration promoted the adhesion of small-particle sediment at the entrance of the flow channel and accelerated the clogging of the flow channel entrance. The Dra and Cu of dripper were 9.0～18.7 percentage points and 16.2～36.4 percentage points lower than those without aerated treatment. The above were the main reasons for aeration aggravates the clogging of the dripper. It was suggested that lateral flushing should be carried out to reduce the risk of channel entrance clogging and improve the anti-clogging capability of aeration drip irrigation dripper.

Key words:drip irrigation;labyrinth path;aeration;sediment particle size;clogging