Research On Optimal Design Of Irrigation Pipeline System Based On Enumeration Method And Genetic Algorithm

China is a country with a serious shortage of water resources,although the total water resources ranked sixth in the world,but too much population led to the per capita possession of water resources is only a quarter of the world per capita.The lack of water resources has seriously restricted the development of China's industrial and agricultural industry,and become a bottleneck restricting China's economic and social development.In the absence of water resources,water pollution,water waste is increasing,further exacerbating the contradiction between water supply and demand and the degree of shortage.China is a big agricultural country,agricultural water consumption ranks first in the industry,and the agricultural water accounts for 63% of the total water consumption in the country.Irrigation water consumption accounts for more than 90% of total agricultural water consumption.With the development of the national economy,the contradiction between agriculture and water resources is becoming more and more acute,and extensive irrigation methods and backward irrigation techniques in many areas no longer meet the requirements of sustainable development.The urgent problems at present is in the case of limited water resources,efficient use of agricultural water,to ensure food security and sustainable production under the premise of reducing agricultural water consumption.This requires us to vigorously develop water-saving irrigation technology,fully tap the agricultural irrigation water-saving potential,improve the utilization coefficient of agricultural irrigation water to ease the water crisis to solve the contradiction between water supply and demand in China.pipeline water is one of the important ways of the development of water-saving agriculture.In the previous engineering design,the pipeline along the field road layout,pipe diameter mostly based on the water supply to determine the water supply,design,construction standards are inconsistent,related parameters mainly by experience and the conventional design,lack of optimization scheme comparison,engineering design planning is difficult to achieve the optimal state,resulting in the increase of project costs and energy consumption.At the same time,farmers can not afford to pay the high irrigation costs,water rate becomes difficult,leading to the actual water price is much lower than the cost of water,seriously restricting the operation and development of irrigation.The research object of this paper is the irrigation pipeline system of small farmland water conservancy project.Based on the comprehensive analysis of domestic and foreign research on pipe network optimization and optimization theory and technology,aiming at the problems and shortcomings of the current optimization design of irrigation pipeline system,the nonlinear optimization model of farmland pressure pipe system is established in terms of water users by taking pipeline length,pipe diameter,pump head as variables,the minimal water supply cost and the annual cost as objective function,and then carried out the pipe network layout optimization and pipe diameter optimization.When the pipe network is optimized,According to the principle of single point of water supply,the enumeration method is adopted for pipe network layout optimization combined with the designers' experience and the practical project,meanwhile compiled C++ program by CodeBlocks.On the basis of this,genetic algorithm is used to optimize the pipe diameter,the most economical pipe diameter combination and the pump head are obtained.The resulting pipe diameter is the standard commercial diameter,which avoids the deviation of the optimization results resulting from discontinuities in diameter.Finally,the minimal irrigation water supply cost scheme is selected as the optimal design scheme.Moreover the Matlab programs are written.Finally,the optimal design model and optimization method are validated by engineering examples.The results show that this method can determine the overall optimization scheme of irrigation piping system quickly and effectively,and meet the requirements of farmland irrigation while reducing the water supply cost effectively and protecting the interests of farmer in irrigation water.