[Paper Review] Pulsatile flow and heat transfer of a magneto-micropolar fluid through a stenosed artery under the influence of body acceleration

G.C. Shit, Malabika Roy|arXiv (Cornell University)|Sep 24, 2012

Nanofluid Flow and Heat Transfer21 references3 citations

TL;DR

This study investigates pulsatile blood flow in a stenosed artery under magnetic fields and periodic body acceleration using a micropolar fluid model to capture microstructural effects. Results show that increasing the Hartmann number reduces wall shear stress but enhances heat transfer, while body acceleration amplifies flow oscillations and fluid acceleration, offering control mechanisms for medical applications like MRI and surgical flow management.

ABSTRACT

With an aim to investigate the effect of externally imposed body acceleration and magnetic field on pulsatile flow of blood through an arterial segment having stenosis is under consideration in this paper. The flow of blood is presented by a unsteady micropolar fluid and the heat transfer characteristics have been taken into account. The non-linear equations that governing the flow are solved numerically using finite difference technique by employing a suitable coordinate transformation. The numerical results have been observed for axial and microrotation component of velocity, fluid acceleration, wall shear stress(WSS), flow resistance, temperature and the volumetric flow rate. It thus turns out that the rate of heat transfer increases with the increase of Hartmann number $H$, while the wall shear stress has a reducing effect on the Hartmann number $H$ and an enhancing effect on microrotation parameter $K$ as well as the constriction height $δ$.

Motivation & Objective

• To model pulsatile blood flow in a stenosed artery considering micropolar fluid behavior due to suspended microelements like erythrocytes.
• To analyze the influence of an external magnetic field (via Hartmann number) on velocity, microrotation, and heat transfer characteristics.
• To investigate the impact of periodic body acceleration on flow resistance, wall shear stress, and volumetric flow rate.
• To evaluate how microstructural parameters (e.g., microrotation parameter K) and stenosis severity affect hemodynamic forces.

Proposed method

• A two-dimensional, axially symmetric, unsteady, incompressible micropolar fluid model is used to represent blood flow in a stenosed arterial segment.
• The governing non-linear partial differential equations are transformed using a coordinate transformation to handle the stenotic geometry.
• Finite difference method is employed to numerically solve the transformed equations under periodic boundary conditions.
• The model incorporates magnetic field effects via the Lorentz force, represented by the Hartmann number H.
• Body acceleration is modeled as a time-periodic function to simulate physiological or environmental whole-body motion.
• Heat transfer is analyzed by solving the energy equation alongside momentum and microrotation equations.

Experimental results

Research questions

• RQ1 How does the application of a magnetic field (Hartmann number) affect wall shear stress and flow resistance in a stenosed artery?
• RQ2 What is the influence of periodic body acceleration on the amplitude and frequency of pulsatile flow and fluid acceleration?
• RQ3 How do micropolar fluid parameters (e.g., microrotation parameter K) affect axial velocity and temperature distribution?
• RQ4 To what extent does stenosis severity (constriction height δ) alter hemodynamic resistance and wall shear stress?
• RQ5 How does the magnetic field influence heat transfer characteristics in blood flow, particularly temperature rise and thermal equilibrium?

Key findings

• Wall shear stress (WSS) decreases with increasing Hartmann number H, indicating magnetic field reduces hemodynamic stress on vessel walls.
• The peak value of wall shear stress oscillations diminishes with higher Hartmann numbers, suggesting magnetic fields can stabilize flow dynamics.
• Volumetric flow rate decreases with increasing Hartmann number H and microrotation parameter K, but increases with higher body acceleration amplitude.
• Fluid acceleration increases with body acceleration amplitude but decreases with increasing Hartmann number, indicating magnetic fields suppress fluid inertia effects.
• Flow resistance increases significantly beyond 25% stenosis severity, with further rise under higher H and K, highlighting critical thresholds for hemodynamic risk.
• Heat transfer rate increases with Hartmann number, and temperature stabilizes at high magnetic field strengths, suggesting potential for magnetic hyperthermia in therapeutic applications.