This study computationally investigates the hydrodynamics of different serpentine flow field designs for redox flow batteries, which considers the Poiseuille flow in the flow channel and the Darcy flow porous substrate. Computational Fluid Dynamics (CFD) results of the in-house developed code based on Finite Volume Method (FVM) for conventional serpentine flow field (CSFF) agreed well with those obtained

In recent times there has been an increasing demand for non-conventional sources. Despite this, the fluctuating nature of nonconventional energy sources poses an immense challenge for far-reaching applications and efficient substitution of conventional sources. Thus, energy storage technology has a decisive role in delivering electric power from non-conventional sources. Of late, several technologies in energy storage have been proposed. These are characterized by distinct development levels and include pumped hydro, electrochemical, thermal, compressed air, flywheel, etc., among others [

Earlier studies analyzed flow field design to attain uniform distribution with low

A comparison study on the hydrodynamics of serpentine and interdigitated flow fields was performed [

A cell design with many slits at the inlet and outlet section provided a more uniform flow with the decrease in

A review of RFBs on flow distribution, localized current distributions, limiting and maximum current densities, shunt currents and pressure distributions carried out [

The physical system under investigation is described in

Mass and momentum conservation for incompressible fluid flow are modeled as follows:

Mass conservation in flow

Momentum conservation in flow channel

For flow through channel,

For flow through porous media,

To reveal the hydrodynamics of the flow fields, CFD analysis are conducted using in-house developed code based on FVM with 2^{nd} order upwind differencing method for treating convective terms. The SIMPLE algorithm is used to couple the pressure and velocities on staggered grid arrangement with pressure being descriterised using 2^{nd} order scheme. The porous substrate is modeled by the addition of source term to the momentum equation. This comprises of two components, a viscous loss term (first term) and an inertial loss term (the second term) in

In the present work, experimental (CSFF) and CFD analysis were conducted to reveal the hydrodynamics of flow in four different channels (CSFF, MSFF1, MSFF2 & MSFF3) for different flow rates

Results from the simulations are presented in terms of Velocity distribution, Pressure distribution in Channel and porous substrate, Non dimensional Velocity distribution in Channel, Non dimensional Pressure distribution in porous substrate and Pressure drop for various flow rates for different channels. These are discussed in the proceeding sections.

The velocity distribution in the channels of all four field configuration obtained from the simulation for flow rate of

From the experimental study of CSFF and CFD analysis for different flow fluid designs for different flow rates

Development of the CFD in-house code based on FVM and its validation with the experimental results.

Experimental results and CFD analysis of CSFF design are in very close agreement within a percentage deviation in

The

Comparing the relative magnitudes of flow velocity in channels and porous substrate for all the designs, the velocity distribution in the porous substrate was two orders lesser in magnitude as compared with flow in channel. Also by observing the velocity penetration across the porous substrate for all the designs, its penetration was found to be more in MSFF2 when compared to the other designs. This increases its wetting ability that is very important in terms of mass transfer over potential for electrochemical reaction happening in the porous substrate to achieve effective electrochemical cell performance.

From the results and discussion, it can be inferred that the MSFF2 design outperformed the other designs with minimum pressure drop and maximum wettability of porous substrate, which are very important for effective electrochemical cell performance.

The authors gratefully thank the Centre for Incubation, Innovation, Research and Consultancy (CIIRC), Jyothy Institute of Technology and Sri Sringeri Sharadha Peetam for supporting this research. K.Kadirgama would like to acknowledge Malaysia Minister of Higher Education for providing financial assistant under Fundamental Research Grant Scheme (FRGS) No. FRGS/1/2019/TK07/UMP/02/3 and Universiti Malaysia Pahang (UMP) under Grant No. RDU192207.

Conventional Serpentine Flow Field

Modified Serpentine Flow Field,

Volume flow rate

Mean velocity in channel

Inlet velocity

Pressure in channel

Inlet pressure

Permeability

Velocity vector

Inertial resistance factor

Density of fluid (Electrolyte)

Dynamic viscosity of fluid (Electrolyte)

Acceleration due to gravity

Gradient operator

Source term

Porosity of substrate (Electrode)

Pressure drop