Experimental characterisation of flow regimes in various porous media—I: Limit of laminar flow regime

Seguin, D.; Montillet, Agnès; Comiti, Jacques

doi:10.1016/s0009-2509(98)00175-4

Cited by 149 publications

(78 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, flow within a flow-through porous electrode may resemble that within a packed bed of particles, where the characteristic length is taken as the average diameter of the particles. In such a configuration, flow is deemed to be within the laminar flow regime for a Reynold's lower than 180 [166], [167].…”

Section: Co-laminar Flow Cellsmentioning

confidence: 99%

Co-laminar flow cells for electrochemical energy conversion

Goulet

Kjeang

2014

Journal of Power Sources

104

View full text Add to dashboard Cite

A recently developed class of electrochemical cell based on co-laminar flow of reactants through porous electrodes is investigated. New architectures are designed and assessed for fuel recirculation and rechargeable battery operation.Extensive characterization of cells is performed to determine most sources of voltage loss during operation. To this end, a specialized flow cell technique is developed to mitigate mass transport limitations and measure kinetic rates of reaction on flow-through porous electrodes. This technique is used in in conjunction with cyclic voltammetry and electrochemical impedance spectroscopy to evaluate different treatments for enhancing the rates of vanadium redox reactions on carbon paper electrodes. It is determined that surface area enhancements are the most effective way for increasing redox reaction rates and thus a novel in situ flowing deposition method is conceived to achieve this objective at minimal cost. It is demonstrated that flowing deposition of carbon nanotubes can increase the electrochemical surface area of carbon paper by over an order of magnitude. It is also demonstrated that flowing deposition can be achieved dynamically during cell operation, leading to considerably improved kinetics and mass transport properties. To take full advantage of this deposition method, the total ohmic resistance of the cell is considerably reduced through design optimization with reduced channel width, integration of current collectors and reduction of reactant concentration. With electrodes enhanced by dynamic flowing deposition the cell presented in this study demonstrates nearly a fourfold improvement in power density over the baseline design.Producing more than twice the power density of the leading co-laminar flow cell without the use of catalysts or elevated temperatures and pressures, this cell provides a lowcost standard for further research into system scale-up and implementation of co-laminar flow cell technology. More generally, the experimental technique and deposition method developed in this work are expected to find broader use in other fields of electrochemical energy conversion. am also very grateful to my graduate colleagues at SFU and friends in FCRel, with a special mention to Omar in particular, for all the pleasant conversations and good times.I wish there had been more.Last but not least, I'd like to acknowledge all the family and friends I was unable to spend quality time with due to this work. I look forward to seeing you all again.vi Tables Table 1. for their higher specific energy and energy density [6]. For the same reasons, the lower power (< 100 W) market which is driven by portable consumer electronics, is currently 2 dominated by closed cell lithium ion batteries in particular [7]. As these batteries reach their limits and fail to keep up with the energy requirements of modern electronics, micro fuel cells with passively pumped higher energy density liquid reactants such as methanol have been suggested as a potential replacement [8].Regardless...

show abstract

Section: Co-laminar Flow Cellsmentioning

confidence: 99%

Co-laminar flow cells for electrochemical energy conversion

Goulet

Kjeang

2014

Journal of Power Sources

104

View full text Add to dashboard Cite

show abstract

“…The occurrence of transition to turbulence is a complex function of size and shape of spacers and packing characteristics. Previous studies on packed beds [20][21][22][23] indicate that transition occurs in the Reynolds number range of 300-400 (based on particle diameter). Unfortunately, there are no such reported studies on the transition to turbulence in spacer filled channels.…”

Section: Transition To Turbulence In Spacer Filled Channelsmentioning

confidence: 99%

Fluid dynamics of spacer filled rectangular and curvilinear channels

Ranade

Kumar

2006

Journal of Membrane Science

125

View full text Add to dashboard Cite

“…With regard to the flow regime many authors [3,4,5,6] agree that, in a generic porous media, a transition from laminar to turbulent flow will occur at a critical Re number. The flow regime occurring in the media for a particular pressure gradient is strictly dependent on the geometrical parameters, the porosity and the pore size.…”

Section: Introductionmentioning

confidence: 99%