A Study on Solute Dispersion in a Three Layer Blood-like Liquid Flowing through a Rigid Artery (original) (raw)
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Acta Mechanica, 2009
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Malaysian Journal of Fundamental and Applied Sciences, 2021
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Dispersion of a solute in pulsatile non-Newtonian fluid flow through a tube
Acta Mechanica, 2012
The unsteady dispersion of a solute by an imposed pulsatile pressure gradient in a tube is studied by modeling the flowing fluid as a Casson fluid. The generalized dispersion model is applied to study the dispersion process, and according to this process, the entire dispersion process is expressed in terms of two coefficients, the convection and the dispersion coefficients. This model mainly brings out the effects of yield stress and flow pulsatility on the dispersion process. It is observed that the dispersion phenomenon in the pulsatile flow inherently differs from the steady flow, which is due to a change in the plug flow radius during a cycle of oscillation. Also, it was found that the dispersion coefficient fluctuates due to the oscillatory nature of the velocity. It is seen that the dispersion coefficient changes cyclically, and the amplitude and magnitude of the dispersion coefficient increases initially with time and reaches a non-transient state after a certain critical time. It is also seen that this critical time varies with Womersley frequency parameter and Schmidt number and is independent of yield stress and fluctuating pressure component. It is observed that the yield stress and Womersley frequency parameter inhibit the dispersion of a solute. It is also observed that the dispersion coefficient decreased approximately 4 times as the Womersley frequency parameter increases from 0.5 to 1. The study can be used in the understanding of the dispersion process in the cardiovascular system and blood oxygenators.
Effect of body acceleration on dispersion of solutes in blood flow
Acta mechanica, 2011
The unsteady dispersion of a solute in blood flow modeling blood as a Newtonian fluid under the influence of a body acceleration is studied using the generalized dispersion model proposed by Gill and Sankarasubramanian . As a result, the total process of dispersion can be described in terms of a simple diffusion process with the effective diffusion coefficient as a function of time. The model brings out mainly the effect of body acceleration and radius of the artery on the overall dispersion process. In the absence of body acceleration, the dispersion coefficient is found to increase rapidly and maintains a steady value in aorta while in other arteries it oscillates about a mean value after reaching it. Body acceleration is observed to enhance the value of the dispersion coefficient in all arteries. The effective diffusivity is found to depend on body acceleration. In the presence of body acceleration, it is noticed that there is a decrease in the effective diffusivity in aorta, femoral, and carotid while in coronary it is increased.
Hydrodynamic Dispersion of Solute under Homogeneous and Heterogeneous Reactions
International Journal of Heat and Technology, 2019
The present investigation deals with Taylor dispersion of reactive species in Casson liquid in an oscillatory flow because of the pulsatile pressure gradient. The solute is considered to be chemically active at the boundary and also participate a first order reaction within the bulk flow. To evaluate transport coefficients, Aris-Barton moment technique is considered. The solute transport process is discoursed in detailed with respect to yield stress, chemical reaction parameter, Womersly number etc. The study reveals that both wall absorption and bulk flow reaction have a significant response on dispersion phenomena. Both the chemical reactions agree to diminish the negative exchange coefficient and the apparent dispersion coefficient, however, increases the negative convection coefficient. The negative exchange coefficient is independent of yield stress but a significant variation is observed due to yield stress in the cases of negative convection coefficient and the apparent dispersion coefficient. The axial distribution of mean concentration is approximated by using the Hermite polynomial representation of central moments as a function of reaction rate parameters, wall absorbing parameter, yield stress etc. The present article may be useful for the studies related to physiological blood flow analysis.
Acta Mechanica, 2006
The dispersion of a solute in the flow of a Casson fluid in an annulus is studied. The generalized dispersion model is employed to study the dispersion process. The effective diffusion coefficient, which describes the whole dispersion process in terms of a simple diffusion process, is obtained as a function of time, in addition to its dependence on the yield stress of the fluid and on the annular gap between the two cylinders. It is observed that the dispersion coefficient changes very rapidly for small values of time and becomes essentially constant as time takes large values. In non–Newtonian fluids the steady state is reached at earlier instants of time when compared to the Newtonian case and the time taken to reach the steady state is seen to depend on the values of the yield stress. It is observed that a decrease in the annular gap inhibits the dispersion process for all times both in Newtonian as well as in non–Newtonian fluids. When the yield stress is 0.05, depending upon the size of the annular gap (0.9–0.7) the reduction factor in the dispersion coefficient varies in the range 0.58–0.08. The application of this study for understanding the dispersion of an indicator in a catheterized artery is discussed.