Theoretical comparison of rheological properties of high-viscosity municipal sludge and magnetic liquid

The composition and structure of sludge determine its complex rheological properties. When the shear stress is small, the deformation of the structural skeleton appears elastic. As the shear stress increases, the structural skeleton begins to break until it is completely destroyed. In this process, it shows viscoelasticity, and its viscosity gradually dominates. A part of the basic fluid flows out from the damaged structural skeleton, causing the sludge to change from deformation to flow, the shear stress at which it starts to flow is called the yield stress. After the flow, the viscosity decreases with the increase of the shear rate, which is called the shear thinning characteristic. Magnetic fluid is a new type of magnetically sensitive smart material. In the past fifty years, a large number of results have been achieved in the research on the rheological properties of magnetic fluids. However, due to the extremely complex anisotropic structure formed inside the magnetic fluid under a magnetic field. At the same time, the macro-rheological experiment lacks systemicity, and it is urgent to integrate the research results obtained by different experimental methods. Even in the field of the most fully studied magnetic viscosity effect, based on strong idealization assumptions the chain-micro-model is widely used, it cannot be used to analyze the results of macroscopic rheological experiments.