Porous Wire Research Articles

Optimization of solar air heaters performance using parallel porous wire mesh: energy, exergy, and enviro-economic analyses

This research conducts an experimental analysis of a solar air heater (SAH) with and without a porous wire mesh, focusing on energy, exergy, and enviro-economic aspects. Measurements are carried out using both a conventional solar air collector and modified one by adding a porous wire mesh. Various wire mesh lengths (20, 40, and 60 cm) are used to determine the optimum one considering different mass flow rates (ṁ = 0.022, 0.033, and 0.045 kg/s). The impact of specific loss sources on exergy efficiency, including exergy destruction between the environment and system components, between the fluid and absorber, and between the absorber and the sun is pointed out. The findings reveal a remarkable enhancement in thermal efficiency, reaching 86 % by using a 60 cm wire mesh atṁ = 0.045 kg/s. The integration of the wire mesh into the SAH results in reduced exergy efficiency due to increased losses and exergy destruction rates. Using 60 cm wire mesh yields beneficial effects on thermo-hydraulic performance by enhancing convection heat transfer and increasing the overall effectiveness of the collector. Enviro-economic analysis shows significant environmental benefits. In Case4, operating at ṁ = 0.045 kg/s, the highest embodied energy value is observed and the highest annual useful energy output of 5480 kWh/year at the lowest energy cost of 0.0105 ($/kWh) is achieved. Additionally, the incorporation of a 60 cm porous wire mesh leads to an annual mitigation of approximately 1370.21 tons of CO2 and an improved environmental cost of 68.51 $/year compared to the conventional solar air collector's cost (28.15 $/year).

Research on the cooling performance of gas generators by porous wire mesh

The gas bladder is essential to the submunition delivery system, performing high-temperature and high-pressure gas scouring and ablation. In this paper, a new gas generator device containing wire mesh is designed to prevent ablation and breakage of the gas bladder. To verify the cooling effect of the device, simulation software is used to simulate the gas flow process and the gas cooling effect of the gas generator. The comparison with the experimental results shows that the error of the calculation results is small and the simulation model is accurate and reliable. Based on the method mentioned earlier, simulations were conducted for different wire porosities and filling thicknesses. The results showed that the cooling effect of the gas generator increased and then decreased with the thickness of the wire mesh and the cooling performance of the wire mesh was the best when the filling thickness was 10 mm. When the filling thickness is 10 mm, the temperature drop and the pressure drop decrease with increasing wire porosity.

Capillary Property of Entangled Porous Metallic Wire materials and Its Application in Fluid Buffers: Theoretical Analysis and Experimental Study

Strong impact does serious harm to the military industries so it is necessary to choose reasonable cushioning material and design effective buffers to prevent the impact of equipment. Based on the capillary property entangled porous metallic wire materials (EPMWM), this paper designed a composite buffer which uses EPMWM and viscous fluid as cushioning materials under the low-speed impact of the recoil force device of weapon equipment (such as artillery, mortar, etc.). Combined with the capillary model, porosity, hydraulic diameter, maximum pore diameter and pore distribution were used to characterize the pore structure characteristics of EPMWM. The calculation model of the damping force of the composite buffer was established. The low-speed impact test of the composite buffer was conducted. The parameters of the buffer under low-speed impact were identified according to the model, and the nonlinear model of damping force was obtained. The test results show that the composite buffer with EPMWM and viscous fluid can absorb the impact energy from the recoil movement effectively, and provide a new method for the buffer design of weapon equipment (such as artillery, mortar, etc.).

Fabrication of a 3D Porous Silver Wire Based on a Template-Assisted Electroless Deposition Method

Porous metal wires are promising in various applications, such as catalysis, energy storage and conversion, electrochemical sensing, and so forth. However, controllable fabrication and structural tuning of porous metal wires remains a daunting challenge. Here, we report the fabrication of 3D porous silver wires based on a template-assisted electroless deposition (ELD) method using an electrospinning-derived elastomer yarn as the template. After the calcination, the elastomer yarn with the deposition of silver nanoparticles can be converted into a 3D porous metallic silver wire with a conductivity higher than 3600 S/cm and a porosity of 86%. The porous structure of the wire could be tuned by changing the repeating cycles of the ELD process for loading silver nanoparticles. More importantly, the electrospinning-based fabrication strategy enables us to incorporate an insulating fibrous layer on the silver wire to impart advanced functionalities. As a proof of concept, a porous silver wire containing a concentric layer of SiO2 microfibers was prepared, and its application as a wire-shaped capacitor for liquid sensing was demonstrated. Benefitting from its completely inorganic nature, high porosity, and chemical stability, the composite wire could sense various organic solvents as well as aqueous solutions with high sensitivity, reliability, and long-term-use stability.

A flexible and self-supported nanoporous gold wire electrode with a seamless structure for electrochemical ascorbic acid sensor

A flexible and self-supported nanoporous gold (S/NP-Au) has been produced using a simple, green, and quick approach for the electrochemical detection of l-ascorbic acid (AA). The dealloying process was used to create the main porous gold wire, and then electrochemical anodizing was adopted to construct the fine structure for nanoporous electrode. Furthermore, followed by chemical reduction with the enediol group in AA, the surface of S/NP-Au wire changed from a laminated to a scattered structure, and the preferred Au (2 0 0) high-index plane was investigated. As a result of synergistic electrocatalytic activity of Au wire skeleton towards AA, amperometric AA electrochemical sensors based on the S/NP-Au wire electrodes exhibit linear detection ranges with ultrahigh sensitivities at a low potential of 0.20 V (vs Ag. AgCl). The detection range of 0.3 μM–923.3 μM with a short response time of less than 1 s gives rise to ultralow detection limit of 26.3 nM (S/N = 3). The excellent characteristics of this sensor demonstrates it is a useful tool for accurate determination of AA in commercially available beverages such as water-soluble beverages with recoveries of 97.35 % to 110.7 %. The S/NP-Au electrode is a promising material for non-enzymatic AA detection.

Electroanalytical sensing of trichloroacetic acid based on activated self-supported porous silver wire prepared by voltammetric etching with trichloroacetic acid as etchant

• Self-supporting highly active porous silver electrodes fabricated by a simple voltammetric etching method. • Increase in electrode active sites by creating a molecular imprinting-like effect during preparation. • Interfacial contact failure caused by excessive dissolution is blocked by the embedding of TCA molecules in micro-nanostructures. • The electrode exhibits good electrocatalytic activity and enables the electrochemical detection of TCA. A novel approach has been designed using trichloroacetic acid as etching molecule to prepare a highly activated self-supporting porous silver electrode for electrochemical detection of trichloroacetic acid. By analyzing the molecular structure, it contains three carbon-chlorine bonds, which can be controlled to form and break the silver-chlorine bonds. It is speculated that trichloroacetic acid molecules can be embed into micro-nano structures through Ag-Cl 3 CCOOH bonding, thus blocking the interface contact failure caused by excessive dissolution of AgCl and displaying the gate effect of imprinted trichloroacetic acid molecules. The performance of the electrochemical sensor constructed by trichloroacetic acid etching are significantly improved. Under the optimal conditions, the determination of TCA was performed with a linear range of 0.05 – 313.20 μmol·L −1 and a detection limit of 0.035 μmol·L −1 . The electrochemical sensor has good reproducibility and stability with relative standard deviations of 4.5% and 3%, respectively, and still achieve 95% of the initial current value after two weeks.

Lateral hysteretic behavior of a novel metal rubber bridge bearing

In this paper, a novel metal rubber bearing is proposed as an alternative to the conventional rubber bearings for small- and medium-span highway bridges to solve the aging-related issues of conventional rubber bearings such as chemical degradation and erosion. The bearing is made of porous metal wire by coiling, weaving and cold-pressing to specific shapes. A shear test program is then described on two metal rubber bearings of stainless steel wire with different densities in order to identify the characteristics of hysteretic curves. The effects of shear strain, compressive stress, loading frequency and repeated loading cycles on the hysteretic behavior were investigated. It was found that the lateral hysteretic curves are approximately in bilinear shape, which consists of an initial elastic stage and a post-yield stage. The equivalent damping ratio of the tested bearings was around 20% at 25% shear strain levels and meanwhile increased with the strain levels, indicating an appreciable energy dissipation capacity. In addition, stiffness degradation was observed for the hysteretic curves beyond a certain deformation limit due to the plastic deformation caused by wire delamination and bearing bulging. However, beyond this limit, the bearing could still work as a unit with stable hysteretic behavior. These characteristics make the metal rubber bearing a great candidate for the conventional rubber bearings. It was also found that the hysteretic behavior is related with a variety of parameters such as density, loading frequency and compressive stress. Finally, it was found that the Bouc-Wen model with appropriate input parameters representing the mechanical properties can accurately simulate the hysteretic curves of the proposed bearings.

Numerical and experimental evaluation for density-related thermal insulation capability of entangled porous metallic wire material

Entangled porous metallic wire material (EPMWM) has the potential as a thermal insulation material in defence and engineering. In order to optimize its thermophysical properties at the design stage, it is of great significance to reveal the thermal response mechanism of EPMWM based on its complex structural effects. In the present work, virtual manufacturing technology (VMT) was developed to restore the physics-based 3D model of EPMWM. On this basis, the transient thermal analysis is carried out to explore the contact-relevant thermal behavior of EPMWM, and then the spiral unit containing unique structural information are further extracted and counted. In particular, the thermal resistance network is numerically constructed based on the spiral unit through the thermoelectric analogy method to accurately predict the effective thermal conductivity (ETC) of EPMWM. Finally, the thermal diffusivity and specific heat of the samples were obtained by the laser thermal analyzer to calculate the ETC and thermal insulation factor of interest. The results show that the ETC of EPMWM increases with increasing temperature or reducing density under the experimental conditions. The numerical prediction is consistent with the experimental result and the average error is less than 4%.

Quasi-static and low-velocity impact mechanical behaviors of entangled porous metallic wire material under different temperatures

To improve the defense capability of military equipment under extreme conditions, impact-resistant and high-energy-consuming materials have to be developed. The damping characteristic of entangled porous metallic wire materials (EPMWM) for vibration isolation was previously investigated. In this paper, a study focusing on the impact-resistance of EPMWM with the consideration of ambient temperature is presented. The quasi-static and low-velocity impact mechanical behavior of EPMWM under different temperatures (25 °C–300 °C) are systematically studied. The results of the static compression test show that the damping energy dissipation of EPMWM increases with temperature while the nonlinear damping characteristics are gradually enhanced. During the impact experiments, the impact energy loss rate of EPMWM was between 65% and 85%, while the temperatures increased from 25 °C to 300 °C. Moreover, under the same drop impact conditions, the overall deformation of EPMWM decreases in the temperature range of 100 °C–200 °C. On the other hand, the impact stiffness, energy dissipation, and impact loss factor of EPMWM significantly increase with temperature. This can be attributed to an increase in temperature, which changes the thermal expansion coefficient and contact state of the internal wire helixes. Consequently, the energy dissipation mode (dry friction, air damping, and plastic deformation) of EPMWM is also altered. Therefore, the EPMWM may act as a potential candidate material for superior energy absorption applications.

Performance evaluation of an arched plate solar air heater with porous aluminum wire mesh cylindrical fins

Solar air heater is used to heat air for space heating and drying process, but its low heat transfers between absorber plate and air account for its low thermal performance. Various surface geometries and fin modifications in a solar air heater have improved its thermal performance. The fabrication and performance evaluation of a solar air heater with an arched wavy absorber plate having porous aluminum wire mesh cylindrical fins attached have been investigated. The arched absorber plate design resulted in an increase in the air turbulence and vortex generation, which leads to the breaking of laminar sub-layer near the surface of the absorber plate and improved the heat transfer. In addition, cylindrical porous wire mesh aluminum fins resulted in an increase in the fin porosity which reduces the pressure drop and improved the thermal performance of the solar air heater. Comparative analysis has been carried for different arrangements at three different fluid flow velocities. The arched wavy absorber plate with fins resulted in better thermal performance with a temperature difference in the range of 55–70 °C approx. compared to the other arrangements at a fluid flow velocity of 5 m/s.

Research progress in nucleation and supercooling induced by phase change materials

The supercooling of phase change materials leads to the inability to recover the stored latent heat, which is an urgent problem to be solved during the development of phase change energy storage technology. This paper reviews the research progress of controlling the supercooling and crystal nucleation of phase change materials. The factors affecting the supercooling and crystal nucleation of phase change materials have been classified into three categories: external fields (magnetic field, ultrasound and mechanical vibration, electric field, and microwave), additives (homogeneous and heterogeneous nucleation) and other methods (porous media, wire interference, and surface tension). In this paper, the mechanism that promotes crystallization and nucleation under the action of different methods have been analyzed. Finally, according to the current research situation, the deficiencies in the current research were put forward, and the future research trends prospected.

Liquid penetration in metal wire mesh between parallel plates under normal gravity and microgravity conditions

The dynamics of liquid penetration in porous wire mesh are experimentally studied in this work by particularly considering the influence of gravity. Similar experimental setups are used on the ground and in a drop tower facility in order to compare the experimental results directly. Visualization of the liquid penetrating process is realized by using single-layered wire mesh which is put between a pair of transparent parallel plates. The dependence of wire mesh on the parallel plates is confirmed. The dimensional results show that liquid penetration in the wire mesh stops at an equilibrium height in normal gravity, while the liquid penetrates ceaselessly in microgravity following a parabolic relation between the liquid height and time. The fast rising early period of liquid rise in normal gravity reduces to a slow climbing period in microgravity. Different to that in normal gravity, liquid rises faster in the coarse wire mesh than in the fine wire mesh in microgravity. The effective contact angle of fluid in the parallel plates increases when it changes from normal gravity to microgravity, while it shows weak dependence on the gravity level as well as the pore radii in the wire meshes. Dimensionless analysis is performed to the results. Good consistency is obtained between the dimensionless experimental data and the theoretical solution, providing a generalized explanation to the dynamics of liquid penetration in metal wire mesh under both normal gravity and microgravity environments.

Light‐Induced Activation of Adaptive Junction for Efficient Solar‐Driven Oxygen Evolution: In Situ Unraveling the Interfacial Metal–Silicon Junction

AbstractThe integration of surface metal catalysts with semiconductor absorbers to produce photocatalytic devices is an attractive method for achieving high‐efficiency solar‐induced water splitting. However, once combined with a photoanode, detailed discussions of the light‐induced processes on metal/semiconductor junction remain largely inadequate. Here, by employing in situ X‐ray scattering/diffraction and absorption spectroscopy, the generation of a photoinduced adaptive structure is discovered at the interfacial metal–semiconductor (M–S) junction between a state‐of‐the‐art porous silicon wire and nickel electrocatalyst, where oxygen evolution occurs under illumination. The adaptive layer in M–S junction through the light‐induced activation can enhance the voltage by 247 mV (to reach a photocurrent density of 10 mA cm−2) with regard to the fresh photoanode, and increase the photocurrent density by six times at the potential of 1.23 V versus reversible reference electrode (RHE). This photoinduced adaptive layer offers a new perspective regarding the catalytic behavior of catalysts, especially for the photocatalytic water splitting of the system, and acting as a key aspect in the development of highly efficient photoelectrodes.

Technical Experimental Equipment for Making Porous Wire Samples

Abstract Original experimental technical equipment for making samples in the form of permeable tubes of porous material, i.e. coiled wire. The article describes the construction of the equipment, the processes of forming and pressing the wire semi-product and methods of fixing the ends of the wire product.

Simulation and experimental investigation of fluid flow in porous and non-porous solar air heaters

The porous absorber in the solar air heater gives considerable temperature increment which is shown by computational fluid dynamic simulation and verified experimentally. Experimental analysis on porous (wire screen) and non-porous solar air heaters were carried out to study the heat transfer and friction factor characteristics. The analysis encompasses the investigation on effect of mass flow rate on air temperature increment, thermal efficiency and pressure drop across the test section. The heat transfer parameter is established in terms of Colburn (Jh) factor for porous bed solar air heaters. The effect of friction factor on different geometries for a range of operating Reynolds number (194–591) is presented. Two wire screen matrix (WSM) solar air heater WSM-I and WSM-II were investigated which has different diameter, pitch and porosity. Thermal efficiency increased on introducing the packed wire-screen matrix diagonally in the air flow path. The increase in thermal efficiency for WSM-I and WSM-II were found to be 5–17% and 5–20% respectively with the mass flow rate ranging from 0.01 kg/s to 0.055 kg/s. The collector heat removal factor was found to be 0.95 ± 0.021 for wire mesh absorber and 0.72 ± 0.0073 for conventional type. The pressure drop across the length of the duct was studied to be in the range of 15 ± 0.28 Pa to 17 ± 0.28 Pa and 7 ± 0.16 Pa to 11 ± 0.28 Pa for WSM-I and WSM-II respectively and for conventional type it was between 5 ± 0.20 Pa and 10 ± 0.28 Pa.

Quasi-static axial crushing behaviour and energy absorption of novel metal rope crochet-sintered mesh tubes

This paper presents a novel reinforcement structure for composite tubes, i.e. crochet-sintered mesh tube (CSMT), for energy absorption applications. The CSMTs are fabricated by crocheting, followed by swelling and vacuum solid-phase sintering of super-fine soft 304 stainless steel wire rope twisted with 49 steel wires. This study focuses on their quasi-static crushing response and energy absorption, and investigates the influence of tube diameter and length on these characteristics. Unlike the dense structure of thin-walled metal tubes used at present, the CSMTs have a special porous structure characterised by inter-crocheting and multiple inter-locking rope skeletons and metallurgical bonds. The crushing deformation exhibits progressive folding with collapse of the mesh pores and densification, without fracture under large plastic deformation, and with rope skeleton stretching, bending, twisting and warping. The diameter and length of the CSMTs have a significant effect on the crushing mode and stability. With the same length, the larger the diameter, the better is the stability; the larger the ESR (effective stroke ratio), the higher are the SEA (specific energy absorption) and CFE (crushing force efficiency). With the same diameter, the greater the length, the weaker is the stability; the smaller the ESR, the lower are the SEA and CFE. The CSMT3 with 40 mm length and 35 mm diameter shows the best deformation stability, an ESR of 0.59, and an SEA of 1114.7 J/kg. The CSMT5 with 65 mm length and 35 mm diameter presents the lowest ESR (0.44) and SEA (592.3 J/kg). The CFE values of all the CSMTs are very high and lie in the range of 0.7–1.0. There is no significant initial impact effect. The CSMTs’ lightweight, porous, and continuous wire structure, their long and stable plastic platform, and their collapsing deformation and high crushing force efficiency make them suitable for applications related to energy absorption components. The CSMTs may be used as a new reinforcement structure in composite tubes, and play an important role in the development of the novel structure of thin-walled metal tubes for energy absorbing components.

Heat transfer in rectangular channels with porous wire mesh under impinging jet conditions

Detailed heat transfer distribution in a rectangular channel under an array of impinging air jets was experimentally investigated using transient liquid crystal technique. The jet-to-jet spacing was 4 and the jet-to-surface spacing was 3. The rectangular channel was fully or partially filled with porous wire meshes (filling ratios = 100%, 50% and 25%) and the jet Reynolds numbers ranged from 2500 to 7700. Although the literature data indicated that the porous material enhanced the overall heat transfer rate, the regional heat transfer on the target surface was degraded because of the blockage and breakup of the core jet flow. The heat transfer coefficient was further reduced with an increase in the filling ratio. For the partially filled channel, the porous wire mesh located near the target surface contributed to even lower heat transfer. All the cases demonstrated that the porous material decreased regional heat transfer on the target surface, and the average Nusselt number for the fully filled case was only 50% of the unfilled case. Although the impingement heat transfer was hindered, the reduced variation in Nusselt number could prevent the development of local hot or cold spots in engineering applications.

Investigation of Charpy impact behavior of porous twisted wire material

Abstract

Experimental and numerical investigations on compressive properties of porous twisted wire materials

ABSTRACTWire diameter, sintering parameter, and porosity have great influences on porous structures and compressive properties of the stainless steel porous twisted wire materials with 30–92% porosities. Finer wires, higher sintering temperature, and longer sintering time will lead to narrower pore-size distributions, more compact porous structures, and stronger compressive yield strength. A random pore model and a twisted wire framework model are put forward to simulate the compressive process. The compressive deformation mechanism is a continuous densification process. The simulated and experimental stress-strain curves all exhibit elastic stage, plastic yield platform stage, and final densification stage.

The Structure Analytical Research of Porous Permeable Wire Material

Abstract The details of making technology of porous permeable material with use of wire are allowed to carry out the analytical research of structure and structural characteristics of wire winding body. Its permit for prognostication the final properties of material, that is produced by the following deformation treatment (diameter reduction). Due to the regular organized arrangement of wire, the coil of winding body is considered as a multispan continuous beam, but a contact of coils - as interaction of two cylinders. Possibility of exactly calculation of the contacts between coils is allowed to go over the single fragment displacements into deformation of whole winding body. During research of deformation processes in regards of winding body geometry and used wire mechanical properties, the structural characteristics of porous permeable wire material are expected. The optimal number of winding layers, eliminating the distortion of organized final structure, is established. The material pressure-compactness relation is obtained in order to control the technological conditions of winding and drafting for guarantee the product required properties.