Pores Per Inch Research Articles

A novel battery thermal management system utilizing ultrathin thermal ground planes for prismatic Lithium-ion batteries

Temperature significantly affects the energy efficiency, safety, life and performance of a lithium-ion battery pack in electric vehicles (EVs). High overall temperature and large temperature difference of the battery in fast charging (FC) can cause degradation in performance and even catastrophic failure like a thermal runaway. Besides, the increasing energy density of battery packs limits the space for the thermal management system. Therefore, we developed an ultrathin thermal ground plane-based battery thermal management system (UTTGP-BTMS), which utilizes 0.4 mm thick novel UTTGP with air cooling to dissipate the heat from the gap between batteries. Double-layer high pores per inch (PPI) mesh and wettability modification was adopted to enhance the thermal performance of the UTTGP. Before the evaluation test of the BTMS, the heat generation rates of the batteries in 2.2C to 4C fasting charging conditions are estimated by Bernardi’s model. Then, the thermal performance of the novel battery thermal management system (BTMS) is experimentally investigated under 2.2C to 4C FC regimes at ambient temperatures from 10 °C to 50 °C. The BTMS is able to maintain a battery surface temperature of 55Ah Lithium iron phosphate (LiFeO4, LFP) batteries below 42.7 °C under a 4C charge rate, 57.3 °C at 50°C ambient temperature, respectively, and still achieve good surface temperature uniformity in all cases studied. Compared to a BTMS with copper heat spreaders, the temperature rise temperature non-uniformity, and thermal resistance are reduced by up to 23.3%, 28.4%, and 62.6%, respectively. Besides this, the effects of the pores density of the mesh in the UTTGP-BTMS are also studied by changing the sieve number of mesh, showing that a higher pore density gives better performance under large C-rates. The proposed UTTGP-BTMS showed significant performance with only submillimeter thickness in the thermoregulation of a battery pack, with the potential of being a viable solution for high-power battery thermal management in EVs.

A numerical study integrated with RSM for hydrothermal and entropy performance of porous jet impingement

AbstractThe thermohydraulic and thermodynamic performance of porous jet impingement under pressure drop effect has not yet been jointly published. Thus, the novelty of this work computationally along with the response surface methodology (RSM) optimization approach considers the porous jet impingement performance linked with a pressure drop simultaneously. Also, the current study used a novel multiobjective optimum design study for various design parameters, such as porosity (ε), Darcy number (Da), and pore per inch (PPI), under numerical simulation assessment of forced laminar convection of jet impingement with full and partial metal foam. The influence of various base plate thicknesses (t = 0, 1, 2, and 3 mm), various nanofluids (Al2O3, CuO, SiO2, and ZnO), and the metal foam size percentage (W/L = 0, 0.25, 0.5, 0.75, and 1) on the improvement of the thermohydraulic and thermodynamic performance is also simulated. Results indicated that utilizing pure water and a metal foam size (W/L) of 1 along with a base plate thickness of 0 mm produced the preferable thermohydraulic and thermodynamic performance. Furthermore, according to an optimization analysis, the current study's objective for the thermohydraulic and thermodynamic performance of jet impingement can be achieved using the parameters porosity ε = 0.1, Darcy number, Da = 1, and the PPI = 15. Therefore, this investigation integrating computational fluid dynamics and RSM offers considerable innovation and useful reference for the optimum design of a porous jet impingement cooling.

Fluid flow analysis of the lattice-based ceramic filters in molten metal filter application

The ceramic lattice filters are ideal for various technical applications, including filtration, flow stability, and heat transfer, that could alter the transport characteristics like pressure, permeability, and velocity. The authors presented a computational study based on the fluid flow parameters for four struts-based lattice structures in this work. This study includes seven designs of four struts-based lattice structures systematically created with 30 pores per inch (PPI) and 80% porosity while varying the unit cell sizes and strut diameter. The present computational study has been carried out using the turbulent k-epsilon (k-ε) model with the chosen metal alloy, IN718. The efficacy of the lattice filters has been determined by visualizing the physical parameters like pressure drop and velocity distribution patterns inside the filters. This study concludes that the BCC and the Diamond lattice structures have outperformed the other designs. Moreover, the effects of the variation in the unit cell and strut size have been evaluated for different structures and discussed.

Thermal performance improvement of a LS-2 parabolic trough solar collector using porous disks

This study presents a thorough numerical investigation of a LS-2 parabolic trough collector (PTC) to introduce a manufacturable structure with high performance. This is done by considering all influential parameters such as possible design shapes (full, upward half, and downward half), diameters, spacings, and PPI (pores per inch) of porous materials along with thermal and fluidic features of heat transfer fluid used inside the absorber pipe. It is found that the full-disk cases perform better than half-disk options. Moreover, the thermal efficiency of PTC improves by increasing PPI and the diameter of porous disks, as well as by reducing the space gaps between the disks. Studying the effects of volumetric flow rate and inlet flow temperature shows that the thermal efficiency diminishes by increasing inlet temperature and decreasing flow rate. In addition, the variations of Nusselt number and friction factor for all mentioned parameters are studied, and performance evaluation criteria are developed to assess the simultaneous effects of enhancing heat transfer against increasing the pumping power.

Hydraulic Characterization of Ceramic Foam Filters Used in Aluminum Filtration.

Ceramic Foam Filters (CFF) are frequently used during the filtration of aluminum (Al) melts to produce high-quality products. In the present study, the physical and hydraulic characteristics of alumina (Al2O3)-based CFF from three different suppliers (A, B and C) have been thoroughly investigated. The filters' porosity and pore diameter, i.e., Window and Cell Feret diameters, were measured and the permeability of the different filters calculated based on pressure drop experiments. The comparison of the classification systems of CFF, i.e., Grade and PPI (Pore Per Inch) numbers, using statistical analysis of permeability and Window Feret diameter showed significant variations between the morphological and hydraulic properties of some CFFs of identical Grade and PPI numbers. Moreover, the Fanning friction factor was plotted as a function of interstitial Reynolds numbers (Rei), and laminar, transient, and turbulent flow regimes were identified. The relationship between the Fanning friction factor and the interstitial Reynolds numbers of all the filter samples investigated was processed using regression analysis, and a model equation developed to calculate the pressure drop over the CFF using the Window Feret diameter. The correlation between the experimental pressure drop values and the derived model equation indicates that empirical expressions for calculating the pressure drop over CFFs should be derived based on experimental measurements carried out at the velocity range of the application of the CFF, which is about 10 mm·s-1 for aluminum filtration.

Pore size variation of nano-porous material fixer on the engine bowl and its combined effects on hybrid nano-fuelled CI engine characteristics

Environmental research is currently one of the most significant and pertinent fields of studies. Due to CI engines'unique nature, theyare widely used in densely populated cities for a variety of purposes. However, due to their impropercombustion for various acceptable reasonsat the engine cylinder, they considerably pollute the environment. This study prepared hybrid nano fuel from waste cooking oil by adding Al2O3 (aluminum oxide) and MWCNT (multi-wall carbon nanotubes) particles and adding ZnO (zinc oxide) nanoporous material fixture in the combustion chamber as an attachment for enhancing combustion efficiency to meet the aim of mitigating the CI engine emissions significantly. The research was evaluated in a 5.2 kW CI engine, and the ZnO nano-porous material is fixed to the combustor. Four distinct pores per inch (PPI) nanoporous materials of pore counts such as 60, 45, 30, and 15 PPI were considered to test the fuels such as diesel and hybrid nanofuel. The hybrid nano-fuel was created from the WCO biodiesel by mixing nanoparticles of MWCNT and Al2O3 nanoparticles in the ultrasonicator. The experiments were carried out at different engine loads from no load to full load with a 25% step-up. The performance of the results was compared with conventional diesel fuel with and without ZnO nano-porous material fixtures and ZnO nano-porous material fixtures with different PPI. The result exhibited that the nanoparticles-added biodiesel fuel in 15 PPI has produced less NOx emission, CO emission, and heat release rate by 55.2%, 7%, 26.5%, and 22.67%, respectively, and this combination also exhibited an improvement of 2.62% in the brake thermal efficiency. Finally, the present work proves that better engine characteristics are generally obtained as the pore size of nanoporous materials in the engine bowl gets smaller, and the hybrid nanoparticles usage in the biodiesel fuel ensures more efficient engine combustion, performance, and emission characteristics.

Effect of surface coating on changes in mass and heat rate on hydrophobic layer coated metal foam

The effect of hydrophobic coating on the surface of metal foam 15 pores per inch (PPI) on its basic thermal properties has been successfully analyzed. In addition, the characteristics of untreated metal foam have also been identified through 3-D optical microscope observations, surface morphology, and analytical models of capillary pressure. Metal foam 15 PPI has an average pore diameter of 746.7 m with a fairly even pore size distribution. The surface structure of the ligament is relatively rough with a fairly dense level of density. The super hydrophilic characteristics of metal foam can increase its capillary pressure. The hydrophobic layer on the metal foam surface did not significantly affect the porous surface morphology of the sample. The stability of metal foam in maintaining its intrinsic properties is relatively optimal, metal foam-based wick structure also has good thermal properties.

Secondary electron emission of reticulated foam materials

Complex material surfaces can reduce secondary electron emission (SEE) and sputtering via geometric trapping. In this work, the SEE yields for a range of open-cell reticulated carbon foam geometries are characterized using scanning electron microscopy. The total reduction in the SEE yield from carbon foams with a 3% volume fill density and 10–100 pores per inch (PPI) is shown to be between 23.5% and 35.0%. Contributions of a foam backplate are assessed by experimentally and analytically defining the critical parameter, transparency. The transparency of a foam is quantified and is shown to affect the primary electron angular dependence on the SEE yield. For the same thickness of 6 mm, it is found that higher PPI decreases foam transparency from 32% to 0% and reduces the SEE yield. The SEE yield from carbon foams is also shown to have weaker dependence on the morphology of the surface compared with fuzzes and velvets and less variation across individual sample surfaces due to the rigidity of their ligament structures and isotropic geometries.

Electronical Conductivity Improvement of Carbon-Based Slurry Electrodes Using Carbon Foams for Enhanced Performance in Advanced Electrochemical Energy Storage Systems.

In this work, the novel idea of using a carbon foam to improve slurry electrode systems' electronic and ionic conductivities is introduced and experimentally investigated. Slurries with different mass loadings of 5, 10, and 15 wt % are prepared using steam-activated Norit (from peat) as an active charge carrier with 1 M H2SO4 and distilled water for specifically analyzing the electronic conductivity. A single-pass rectangular flow channel is used in this slurry system, where the channel width is varied from 4.1 to 2.6 cm by changing the current collectors' position and slurry flowing from zero (static) to a maximum of 240 mL·min-1. Carbon foams with two different thicknesses of 10 and 6.5 mm and two different pore sizes of 10 pores per inch (PPI) and 5 PPI are used for this investigation. It is observed that application of the carbon foam improves slurry conductivity; with a 10 mm thick, 10 PPI carbon foam, maximum increases of 204% in electronic conductivity and 23% in ionic conductivity are observed for water-based and acid-based slurries, respectively.

A 3D computational method for determination of pores per inch (PPI) of porous structures

A 3D computational method for determination of pores per inch (PPI) of porous structures

Boiling Heat Transfer in Copper Foam Bilayers in Positive and Inverse Gradients of Pore Density

Gradient metal foam is an advanced heat transfer material that decreases resistance to bubble escape and enhances the transfer of boiling heat. In this study, boiling heat transfer and bubble behavior were studied in an experimental set-up with copper foam bilayers configurated either in positive or inverse gradients, utilizing deionized water as working fluid. Positive gradient refers to arranging metal foam layers with high pore density at the bottom, above the heat source, and low pore density on the top. Results show that the heat transfer is higher for gradient metal foam surfaces, of 6.14×105 W/m2, versus a uniform metal foam surface, of 3.94×105 W/m2. For the positive gradient configuration, boiling heat transfer performance first increased with the pore density, then decreased when the pore density was higher than 60 pores per inch (PPI). By contrast, for the inverse gradient, the heat transfer performance was nearly constant with increasing pore density. At the low pore density, the inverse gradient performed better than the positive gradient during the whole boiling process. At high pore density, the positive gradient structure performed better in heat transfer at the early boiling stage. Three main types of bubble escape were observed: For the positive gradient bilayer, the bubbles moved up or down without lateral interference. In contrast, for inverse gradient, the bubbles mostly escape from the sides, which is easy to induce bubble merging. The inverse gradient surface generates larger bubbles, while the positive gradient surface produces a higher frequency of bubble detachment. Accordingly, two liquid replenishment models are proposed: for the positive gradient, external liquid replenishes from the side into the copper foam, while for inverse gradient, the liquid is mainly replenished from the top.

Unveiling the corrosion perspective of Al-Si alloy/SiC foam interpenetrating phase composite

The corrosion response of the Al-Si alloy/SiC foam interpenetrating phase composite (IPC) has been investigated for the first time in this study. Towards this, SiC foams with varying pores per inch (PPI) index (10, 20, and 30) were employed to fabricate IPCs, designated as, 10PPIC, 20PPIC, and 30PPIC, respectively. The pore size decreased and connectivity of the reinforcement increased with the increase in the PPI index. The electrochemical corrosion studies have revealed that the incorporation of the reinforcing phase in a continuous manner deteriorates the corrosion resistance in all the IPCs except in 20PPIC, where the corrosion resistance is comparable to that of the unreinforced alloy. This is ascribed to the optimum pore size and reinforcement interlinking in this specimen which results in the formation of a less disrupted passive film as well as substantially restricts the pit growth.

Pore-scale simulation of forced convection heat transfer in metal foams with uniform and gradient structures

Because of their large specific surface areas, metal foams are commonly used in studies of enhanced heat transfer. Modified metal foams with gradient structures are often chosen to reduce high pressure drop. Using computational fluid dynamics (CFD), forced convective heat transfer of metal foam samples for uniform and gradient structures with the same porosity and pore per inch (PPI) were investigated. To study the effect of gradient porosity under the premise of constant control porosity. First, heat transfer was examined in relation to gradient orientation. Gradient metal foam showed a 27.25% improvement in overall heat transfer performance when using the arrangement from small to large porosity than in the opposite direction. In addition, their performance was compared with that of uniform metal foam with 10 PPI and 0.88 porosity. The results showed that for 0.88 porosity, the gradient structure reduced the pressure drop by 23.66% and improved the overall heat transfer performance by 12.07% relative to the uniform structure. The gradient structure was better than the uniform structure at a given porosity value. The sudden change in geometry at the gradient interface of a gradient structure caused changes in flow and heat transfer compared to a uniform structure.

Enhanced boiling heat transfer of HFE-7100 on copper foams under overflow conditions

Boiling of dielectric liquids on structured surfaces is a powerful option for thermal management of electronic devices, whose cooling performance depends strongly on liquid supply and vapor departure. Herein, saturation boiling of HFE-7100 on copper foams with a pore density of 30 pores per inch (PPI) under overflow conditions is proposed to enhance liquid supply and facilitate vapor departure. Liquid HFE-7100 is fed to the copper foam by a peristaltic pump and un-vaporized liquid is discharged by gravity. The higher flowrate leads to higher critical heat flux (CHF) and heat transfer coefficient (HTC) only if the copper foam is not flooded. Visual observations reveal evolution of vapor bubbles with heat flux on the copper foam under overflow conditions. Dependence of CHF and HTC on foam thickness is experimentally evaluated and an optimal thickness of 4.7 mm is derived from the experimental data. The optimal foam thickness is related to submergence level of bulk flow and capillary height. CHF and HTC are enhanced by the forced liquid supply in combination with the reduced hindrance of hydrostatic pressure to vapor departure, reaching 860 kW m−2 and 47.3 kW m−2 K−1, respectively. The overflow boiling offers an efficient way to improve heat transfer of boiling on porous medium for efficient thermal management.

A Novel Approach to Water Softening Based on Graphene Oxide-Activated Open Cell Foams

This work focuses on exploring a new configuration for the reduction of water hardness based on the surface modification of polyurethane (PU) open cell foams by the deposition of thin graphene oxide (GO) washcoat layers. GO was deposited by the dip–squeeze coating procedure and consolidated by thermal treatment. The final washcoat load was controlled by performing consecutive depositions, after three of which, a GO inventory up to 27 wt% was obtained onto PU foams of 60 pores per inch (PPI). The GO-coated PU foams were assembled into a filter, and the performance of the system was tested by continuously feeding water with hardness in the 190–270 mgCa2+,eq·L−1 range. Remarkable results were demonstrated in terms of total adsorbing capacity, which was evaluated by measuring the outlet total hardness by titration and exhibited values up to 63 mgCa2+,eq·gGO−1 at a specific filtered water volume of 650 mLH2O·gGO−1, outperforming the actual state-of-the-art adsorbing capacity of similar GO-based materials.

Effect of cell size on the microarchitectural and physicomechanical response in open-cell Al foam made through template method

Fully open interconnected Al-foam having different PPI (Pores per inch) was fabricated through the novel template method. The morphology of the open-cell Aluminium foam (OCAF) (strut, pore, and cell size) can be easily tailored with this method. Three different PPI (10, 20, and 30) Al-foams were fabricated through the template method, and show the effect of PPIs’ on their microstructure, thermal, electrical, and mechanical properties in detail. With different PPI of the foam, the porosity lies in the range of 85–94%. Through experiments, it was found that with the increase in PPI, the density of the foam gets increases. Complete openness and uniformity in terms of the pore, strut size, and porosity throughout the samples has been easily achieved with this method, which is very difficult with previously reported methods. As the PPI of the foam changes, the properties (electrical, thermal, and mechanical) also change. According to the requirement, one can easily tailor the properties by changing the PPI of the foam. Experimentally evaluated properties were also compared with the theoretically calculated values. The open-cell aluminium foam of 30 PPI (OCAF-30) having RD-0.14 shows electrical conductivity- 0.68 × 106 S/m, thermal conductivity- 6.43 W/m.K, and compressive strength of 0.65 MPa. This study helps the research community to fabricate OCAF according to their requirement with desired thermal, electrical, and mechanical properties for the application of heat transfer, electrocatalysis, and others.

Eksperimentalno istraživanje toplotno-hidrauličkih performansi kanala sa pregradama od gradijentne metalne pene

Metal foam is a novel material recently utilized in baffles as an alternative to solid baffles for reducing flow resistance. However, the metal foam baffles are accompanied by low heat transfer efficiency. To overcome this issue, a new design of copper foam baffles has been suggested in this research, called baffles having a gradient pore density of the copper foam. The pore density either increases or decreases towards the wall. So, the experimental tests were carried out in a square channel and heated uniformly at the bottom wall of the test section. Its walls are mounted copper foam baffles at a fixed porosity of 95%. Baffles were alternately fixed upon the walls' bottom and top in staggered mode. The results were determined for various kinds of copper foam (10 and 20) pores per inch (PPI), and the gradient pore density was either with the order decreasing (DPPI) 10/20 PPI or increasing (IPPI) 20/10 PPI with a window cut ratio of 25% and a constant heat flux of 4.4 kW/m2 . The Reynolds number was changed from 3.8x104 to 5.4x104 . The data for conventional copper solid baffles were used to compare the influence of foam metal type. The obtained results revealed an enhancement in thermohydraulic performance for baffles with a gradient pore density of the order decreasing DPPI (10/20 PPI) higher than all the models of copper foam baffles.

Thermal resistance of Open-Cell metal foam with thermal interface materials (TIM)

• This study proposes an alternative joining metal foam with other metals and TIM. • The thermal resistance decreases with increasing compression load and varies with TIM hardness. • The thermal resistance of the hard TIM sample is reduced to a maximum of 62% when a 30N compression load is applied. • The soft TIM sample has a thermal resistance difference of 19% higher than that of hard TIM. This study investigated the thermal resistances of sandwich structures consisting of open-type metal foams, base plates/surfaces, and thermal interface materials (TIMs) in two types of sandwiching configurations, namely Type 1 and Type 2. Samples were prepared using metal foam structures of 20, 40, and 60 pores per inch (PPIs), representing five commercial TIMs, i.e., pyrolytic graphite sheet (PGS), T621, SFT90, PC93, and PC94. They were categorised into two types: (i) thin and hard films (PGS, T621, SFT90) and (ii) thick and soft pads (PC93 and PC94). The thermal resistance and the thickness were measured under compression loadings of 0 – 60 N using an in-house thermal resistance tester developed according to the ASTM D5470 standard. Based on the nanoindentation test, PGS showed the highest hardness (0.2660 GPa), followed by T621 (0.0322 GPa), SFT90 (0.0235 GPa), PC93 (0.0007 GPa), and PC94 (0.0004 GPa). In general, thermal resistances were dependent on compression forces; they decreased with increasing compression loads. At a 30 N load for 60 PPI, the thermal resistance of the hard TIM sample was reduced to 62% with a 1.5% reduction in compression thickness at the Type 1 configuration. The resistance decreased as much as 8% when PPIs increased from 20 to 60. By contrast, at a 30 N load for 60 PPI, the thermal resistance of the soft TIM sample was reduced to 58% with a 16% reduction in compression thickness at the Type 1 configuration. When PPIs increased from 20 to 60, the resistance decreased by just 5%. Despite a lower thermal resistance reduction than the hard TIM, the soft TIM was 19% higher in thermal resistance difference. This study showed that joining metal foam, TIM, and base plate reduced thermal resistances while increasing their performance.

Reinforcement of neutron shielding composites with three-dimensionally interwoven structures via reticulated porous ceramic skeletons

In this study, neutron shielding composites (NSC) with an interpenetrating network structure are prepared with epoxy resin, B4C particles, and reinforced by different pore sizes reticulated porous ceramic skeletons (RPCS). The bonding strength between B4C particles and epoxy resin is improved via the surface modified process. The viscosity of B4C/epoxy resin is decreased with the increase in temperature. As increasing the curing temperature, the time to reach the gelation point decreases. After reaching the gelation point, the composite viscosity of B4C/epoxy resin is increased sharply. Because of adding the RPCS, flexural strength and thermal conductivity of the NSC specimens are increased, while the thermal expansion coefficient is progressively decreased. Compared with the specimen without RPCS, the flexure strength and thermal conductivity of the NSC specimen 30 PPI (pores per inch) are increased by 129.27% and 756%, but the thermal expansion coefficient is reduced by 81.66%. Under the same thickness, the NSC specimens from 10 PPI to 30 PPI, the sub-cadmium neutron (E < 0.4 eV) shielding capacity is increased first and then decreased. The NSC specimen 15 PPI has the best sub-cadmium neutron shielding capacity, the sub-cadmium neutron shielding capacity reaches 80.67% (0.5 cm).

Effect of Copper Foam Baffles on Thermal Hydraulic Performance for Staggered Arrangement in a Duct

Metal foam is a novel material recently utilized in baffles as an alternative to solid baffles for reducing flow resistance. However, copper foam baffles have been suggested in this research to overcome this issue. So, the experimental tests were carried out in a manufactured square channel (250 mm x 250 mm) and heated uniformly at the bottom wall of the test section.Its walls are mounted copper foam baffles at a fixed porosity of 95%.Baffles were fixed alternatively on the top and bottom of the walls in staggered mode between two successive baffles (center to center) and were kept constant at 250 mm. The experimental work was done for different grades of the pore density of copper foam (10, 15, and 20 pores per inch (PPI)) with a window cut ratio of 25% and a constant heat flux of 4.4 kW/m2.Reynolds number was varied from 3.8x104 to 5.4x104. The data for conventional copper solid baffles were used to compare the effect of foam metal baffles.The obtained results manifested that relative to the solid-copper baffles, the copper foam baffles have a greatly lower friction factor, whereas the friction factor for the solid baffles and copper foam baffles (10, 15, and 20) PPI is about (460), and (20, 29, and 38) times, respectively above the smooth surface. Moreover, the results of previous work predicted the present experimental work very well.