Chemical Engineering Seminar Series: Dr. Chandra Sekhar Maurya

Study of Magneto-Induced Rheological and Viscoelastic Properties of Magnetorheological Fluids and Regulation of Blood Flow under the Influence of Magnetic Fields.

The field-responsive features of magnetorheological fluids (MRFs) provide a basis for a wide range of potential applications in automotive and biomedical fields. The settling of micronsized carbonyl iron (CI) particles due to the gravitational effect still is the most significant problem with MRFs. MRFs should have low off-state viscosity and high on-state yield stress with high sedimentation stability. MRFs were prepared using two different methods; first, we used nano-sized magnetic particles with flake-shaped micron-sized CI particles, which fill the voids between micron-sized particles, and the second method was the use of clay additives and surfactants, which can form a three-dimensional clay gel network with CI particles. As a result, the rheological characteristics and suspension stability of MRFs were improved. Magnetoinduced rheological and viscoelastic properties of MRFs under different operating mechanical forces based on their applications in MRF devices are studied along with the validation of experimental results with the theoretical rheological model. Time-dependent shear flow and amplitude sweep tests revealed complete reversibility of rheological and viscoelastic properties of the MRFs with time after destroying the microstructures. Creep and recovery characteristics allow us to understand the MRF flow’s deformation mechanism when a constant stress level and magnetic field are applied. Under the applied magnetic fields, the elastic energy storage capacity of MRFs increases, and the instantaneous creep strain reduces considerably. One of the most prevalent symptoms of heart disease in patients is coronary artery stenosis. Our findings suggest that the blood flow characteristics can be efficiently manipulated by the magnetic field, which can also cause the blood flow to accelerate and decelerate in response to applied magnetic field directions. Furthermore, a dramatic change in the characteristics of blood flow is observed when the stenosis presents near the coronary artery wall. The results of the investigation highlight the consequences of stenosis on the pressure and blood flow developed in coronary arteries, information that could be useful in the development of experimental models for microscale blood flow, and in the early diagnosis of heart attacks. The use of magnetic particles in biomedical domains still has a lot of issues, that are required to address and provide solutions.