Simulation Analysis And Applicability Evaluationof River Bank Filtration Applies To Water Source Heat Pump Development

This paper relies on scientific research project "study on key technical problems of river bank filtration in Beipiao City,Liaoning Province(Baishireservoir)" to carry out engineering hydrogeological research,based on the study of the hydrogeological characteristics of the aquifer in the engineering area,the conceptual model of hydrogeology is constructed,through a variety of field test to determine the aquifer hydrogeological parameters,the three-dimensional numerical simulation software FEFLOW was used to establish the seepage field and the temperature field model of the Beipiao Baishi reservoir,simulation analysis on distribution status and variation characteristics of seepage field and temperature field in engineering area.On the basis of this,taking the Beipiao Baishi reservoir river bank filtration project as an example,the applicability evaluation system of applying the river bank filtration project to the groundwater source heat pump development is established,and the river bank filtration project of Beipiao Baishi reservoir can be evaluated by shallow geothermal energy resources,analyzes the characteristics of groundwater source heat pump based on river bank filtration and the characteristics of traditional water source heat pump,which provides a theoretical basis for the future application of river bank filtration technology to groundwater source heat pump development,Which not only filled the theoretical blank of the river bank filtration technology seepage heat transfer,but also has the economic and practical value of engineering development.The main research results are as follows:(1)According to the geological environment,hydrogeological characteristics of the project area,the hydrogeological structure of the aquifer in the Beipiao Baishi reservoir is established,the riverbed muddy layer is the relative aquifuge of the river flow into the aquifer,the middle coarse sand layer and the sand gravel layer is the main purpose aquifer for the water abstraction project,the Jurassic Beibiao group weathered,the weathered bedrock is the relative aquifuge.(2)Based on the analysis of the hydrogeological structure of the aquifer in the engineering area,the conceptual model of the three-dimensional hydrogeological geology of the engineering area is established,and the seepage field and temperature field of the aquifer under the natural state before the river bank filtration project was carried out.(3)The results of three-dimensional numerical simulation of groundwater seepage during filtration engineering project show: water level down funnel can be formed with the pumping well and water chamber as the center when taking water,when the water intake remained unchanged,there was a positive correlation relationship between the change of aquifer water level and the water level of Baishi reservoir.(4)Considering the influence of the underground corridor on the temperature field around the aquifer: the influence of the groundwater temperature change on the temperature field of the surrounding aquifer is limited to a certain extent and will not have a great influence on the whole form of the temperature field distribution of the aquifer.The influence of the groundwater temperature on the temperature field around the aquifer depends on the specific heat capacity,thermal conductivity and thermal dispersion coefficient of the aquifer.(5)Considering the influence of river water supply on the temperature field of aquifer whentaking water,when the river water temperature changes,river water temperature first affects the aquifer under the action of the formation of water level drop the funnel area,with the passage of time,the scope of influence gradually spread to the entire model area,the effect of river water temperature on the temperature field of the aquifer,which takes 30 to 60 days to spread from the affected water level to the surrounding area.(6)Using the Analytic Hierarchy Process(AHP)to establish the applicability evaluation system of Beipiao Baishi reservoir for dipping water project applied to groundwater source heat pump system development,by considering the conditions of groundwater occurrence,groundwater power field and heat pump unit operating conditions comprehensive evaluation shows,Beipiaoriver bank filtration project has a high applicability to the development of groundwater source heat pump system,and the applicability comprehensive evaluation score is 7.033.(7)On the basis of the present situation of the project,the application of the Beipei diafiltration water project to the groundwater source heat pump system can be carried out with the amount of shallow geothermal energy resources of 1006×108kJ/a,which can replace conventional energy 5715.38t/a standard coal.Compared with the traditional water source heat pump,it is found that the groundwater source heat pump has the characteristics of single well heat transfer power,good water quality,good water quality,little influence on the surrounding environment and secondary utilization of water.