Experimental Study On Rheological Characteristics Of Unban Sewage

In recent years,as China’s comprehensive national strength has rapidly increased,energy consumption has also increased day by day.As the amount of non-renewable energy storage has been drastically reduced,and the burning of fossil fuels has caused serious damage to the global environment and the ozone layer,the development of clean energy is imminent.As a kind of high-quality clean energy,sewage is huge in quantity and contains high heat energy.Its recycling can reduce a considerable part of energy consumption.However,the physical composition of sewage is relatively complex and contains many solid particles,which will reduce the life of heat pumps and other equipment and increase the cost of use.Therefore,it is necessary to study a low-cost,high-efficiency water purification technology.The premise of the research is to study the basic flow characteristics of urban sewage.This article first introduces the establishment of an experimental platform for the rheological characteristics of urban sewage.Since sewage contains solid particles,if a rotary rheometer is selected,the solid particles will be deformed,agglomerated or broken.Therefore,a horizontal tube rheometer was selected to test the rheological characteristics of the sewage.Before the experiment,first measure the concentration of solid particles in the urban primary sewage collected from the underground wells of the residential area,and select the artificial sewage with quartz sand and PC particles according to the measurement results.Secondly,a control experiment of artificially configured sewage and urban native sewage was carried out.Municipal sewage is actually a solid-liquid two-phase fluid.Because the concentration of solid particles in the sewage is very small,and the fluid velocity is small in laminar flow,most of the solid particles settle at the bottom of the pipeline,and there is a large velocity between the solid and liquid phases.Therefore,the sewage at this time can be regarded as a homogeneous single-phase fluid,and the influence of solid particles can be attributed to the viscosity characteristics of non-Newtonian fluid,and the non-Newtonian fluid model can be used to process and study it;while in turbulent flow Under the circumstances,the solid particles are uniformly distributed in the liquid phase under the influence of the turbulence of the liquid phase.The theoretical analysis can be carried out according to the two models of non-Newtonian fluid and multiphase flow.This paper first uses a non-Newtonian fluid model to study the flow characteristics of sewage at different temperatures and concentrations under laminar sewage flow conditions,and obtains the constitutive equations corresponding to different temperatures and concentrations respectively,and combines experimental measurement and theoretical derivation.Obtain the equations of velocity and local drag coefficient in the tube.For turbulent flow conditions,because the experimental data processing is more complicated,only the constitutive equation of sewage at room temperature(20℃)and the semi-empirical formula of velocity and local resistance coefficient are studied.Finally,the solid-liquid two-phase flow model is used to study the flow velocity,average flow velocity,and local resistance coefficient under sewage turbulent flow conditions,and a semi-empirical formula is obtained.