Numerical Simulation Of Turbulent Flow And Heat Transfer Characteristics Of Untreated Sewage In Tubes

With the increasing energy consumption,sewage source heat pump technology has attracted more and more attention.However,in the engineering practice of sewage source heat pump technology,it is found that the serious deposition of the sewage of the sewage source heat pump system causes the pipeline resistance to increase,and the heat transfer coefficient inside the pipe is seriously reduced,resulting in low overall operating efficiency of the system.In addition,when designing and calculating the sewage source heat pump system,there are no relevant calculation parameters,such as the resistance coefficient along the pipeline and the heat transfer coefficient inside the pipe.In this paper,the turbulent flow and heat transfer law of sewage pipe under the action of fouling bottom layer is studied for the flow and heat transfer in sewage pipe,which provides reasonable design parameters for the design of sewage source heat pump engineering system.This research is of great significance to promote the sustainable development of the country,promote the sewage source heat pump technology,and promote the application of sewage source heat pump.Firstly,for the raw sewage in the urban sewage main canal,the organic and inorganic components of the pollutants in the raw sewage were tested and tested,and the parameters such as density,thermal conductivity,viscosity and specific heat of sewage and pollutants were tested.The particle size distribution of suspended waste particles was studied.Secondly,the flow resistance and fouling growth characteristics in the sewage pipe were studied experimentally.The morphological characteristics of the fouling layer deposited on the inner surface of the sewage pipe were tested by image method,and the wall roughness of the surface of the heat exchange tube under the action of the fouling bottom layer was determined.Thirdly,the mathematical model of turbulent flow and heat transfer in the original sewage pipe was established,and the applicability of the model was verified by experimental data.The turbulent flow characteristics,solid-phase concentration distribution characteristics and heat transfer characteristics of the original sewage pipe under the action of the bottom layer of fouling were studied by numerical simulation.The mathematical model of flow resistance and surface heat transfer coefficient in the sewage pipe was established.The flow velocity and fouling of the sewage were analyzed.The effect of the concentration of the material on the flow resistance and heat transfer in the tube.