Design And Hydrodynamic Characteristics Of Micro Head Turbine

In the world energy supply is increasingly tight and fossil energy demand exceeds supply,the development of renewable energy is the only solution.Water resource is a kind of renewable clean energy.Exploiting water resources is one of the most feasible schemes at present.Since the development of high-head hydropower resources has great impact on the environment,and the initial investment is large,and the construction period is long,small and medium-sized hydropower stations and micro-head power generation will be the focus of future development,which is also strongly advocated by the 14 th Five-Year Plan.The use of hydropower to generate electricity will inevitably change the discharge flow from the power station and affect the natural environment.Therefore,the country proposed the concept of ecological flow.Ecological flow refers to the flow(water volume,water level)and processes that need to be retained in rivers and lakes that meet the water quality requirements in order to maintain the structure and function of water ecosystems such as rivers and lakes.However,the ecological flow is usually only 10-30% of the design flow.At this time,the power station can only operate at extremely low efficiency or even unable to operate.Therefore,it is urgent to design a small unit that adapts to the micro-head to replace the original unit to obtain energy for power generation..In addition,my country has nearly 100,000 small reservoirs with a total storage capacity of more than 70 billion cubic meters.They are mostly used for river peak shaving,domestic water use,and farmland irrigation.They have not been used for hydroelectric power generation because the water head is too low.Therefore,the goal of this subject is to complete the design of the micro-head hydraulic turbine under the requirements of maintaining ecological flow,and determine the final design plan based on the results of the numerical simulation,and design a practical flow channel model based on the configuration of the small reservoir gate.Study the hydrodynamic performance of a micro-head turbine in a closed flow channel.This article first analyzes the turbines that may be suitable for micro-head hydropower generation,and chooses the tubular type as the basic type of micro-head turbines.Then,the performance parameters of the water turbine and the operating principle of the water turbine are introduced,the theory and process of designing the blades of the water turbine by the lift method,and the selection method of the basic design parameters of the water turbine are given.According to the previously established design method,this paper gives the design schemes of multiple turbine runners and establishes the geometric model of the turbine based on the value requirements of the basic design parameters.Choose the appropriate CFD numerical simulation method,carry on the numerical simulation research to each design plan,choose the optimal design plan to obtain the final configuration of the micro-head turbine,and finally analyze the flow pattern of the turbine in the throughflow channel after the design plan is determined.According to the actual project,this paper designs a flow channel applied to the outlet of a small reservoir,and obtains the overall efficiency of the micro-head turbine at different flow channel outlet sizes through numerical simulation,determines the flow channel outlet size,and analyzes the The flow pattern of the micro-head turbine in the flow channel,the characteristics of energy loss everywhere,the law of pressure change,and the outlet energy of the turbine.Due to the requirement of ecological flow,a stable discharge flow is required.At the end of this article,the flow of the flow channel is used as the control condition to study the performance of the turbine under different working conditions and the relationship between the changes of various parameters,and the correlation is obtained.The performance curve of the turbine.In addition,the influence of the cavitation effect on the performance of the micro-head turbine is also studied.The research results of this paper will be a micro-head turbine suitable for microhead conditions and a practical flow channel model to obtain various performance parameters of the micro-head turbine.