Design And Research Of Small-scale Power Generation System For Farmland Irrigation Pipeline

With the rapid development of agricultural water conservancy projects,automatic irrigation technology has become the main form of agricultural water-saving irrigation development.A variety of control and monitoring equipment are used in agricultural irrigation,and most of the irrigation areas are remote,so the power supply of the monitoring equipment becomes a problem.Traditional battery capacity is limited,and long-term use will cause insufficient voltage to affect the stable operation of the system,and frequent replacement will cause greater waste of human resources.The use of solar energy,wind energy and other new energy power generation equipment is not only complicated to install,but also difficult to protect from human damage.The use of pipeline water flow power generation system to provide electrical energy can solve the power supply problem of the monitoring equipment and avoid the environmental pollution and waste of human resources caused by other power supply methods.The irrigation pipeline power generation system mainly includes the turbine and the power generation.The pipeline power generation system designed in this paper is installed in a pipeline with a diameter of 100 mm,a water flow rate of 1.5 m/s,and a pressure of 200 k Pa.First,the Solid Works software was used to create three-dimensional models of impellers with different structures,and the fluid analysis software Fluent was used to perform numerical simulation calculation and analysis and comparison,and the best impeller model structure was selected.In this paper,the dynamic grid is used to calculate the speed of different impeller structures under the set conditions.The calculation results show that the impeller rotates in the range of 440 r/min ～ 700 r/min at 45° ～ 60° rotation angle.The impeller rotation speed increases linearly with the rotation angle change,and the impeller rotation speed does not change with the number of blades at the same rotation angle.The law of speed is used to calculate the energy output of the blade when the system is running stably under different impeller structures.The calculation results show that the head loss and output power of the impeller increase with the increase of the rotation angle.And at the same rotation speed,the head loss and output power increase faster when there are fewer blades,and slower when there are many blades.Compared with the energy output of the impeller,combined with the analysis of the pipeline flow field,this paper selects the 7-blade impeller model with a rotation angle of 53 ° as the optimal impeller model for the power generation system.The speed of the turbine is 580 r/min,the output power is 37.9 W,the head loss is 0.379 m,and the output efficiency is82.1%.This paper also designs the control circuit of the power generation system.According to the different energy output capacity of the impeller under different flow conditions of the pipeline,the MPPT maximum power point tracking strategy is used for charging control to ensure that the charging system operates in the best state.In this paper,the Buck circuit is used as the system chopper circuit,the single-chip microcomputer collects and controls the output current and voltage data,and the control program is designed to ensure the long-term stable operation of the power generation system.