Journal Article

Enhanced thermal energy storage using micropolar fluids: A numerical study

Duwairi, Hamzeh, Migdady, Makram, Alrbai, Mohammad

2026

Overview

This study develops and solves a micropolar-fluid model for heat storage in a rectangular duct subject to constant wall heat flux. The dimensionless mass, linear and angular momentum, and energy equations are treated with a Runge-Kutta (for the coupled momentum ODEs) and finite-difference scheme (for the energy PDE). Increasing the coupling parameter raises the dimensionless axial velocity while initially reducing and then increasing microrotation; the net effect is a decrease in dimensionless temperature, indicating diminished storage effectiveness. In contrast, higher spin-gradient viscosity reverses these trends and enhances thermal storage. Reynolds and Prandtl numbers exhibit inverse relationships with the temperature profile. Quantitatively, the mean Nusselt number is ≈ 2.53 at an entrance length of x * ≈ 5.5 , while the local Nusselt number decays approximately exponentially downstream and approaches zero. For a low-inertia case ( Re = 5 ), the peak fluid temperature reached ∼ 95 ∘ C under the imposed heat flux. These results clarify how micropolar parameters govern heat transfer and storage performance, offering guidance for tuning ducts that use micropolar working fluids.

• Publisher: SAGE Publications,Sage Publications Ltd,SAGE Publishing
• Subject: Angular momentum / Energy storage / Finite difference method / Fluid flow / Heat / Heat flux / Heat storage / Heat transfer / Micropolar fluids / Nusselt number / Parameters / Prandtl number / Runge-Kutta method / Temperature profiles / Thermal energy / Thermal storage / Working fluids