Aluminum Plate Research Articles

Effect of the surface form of the herringbone aluminum plate in a plate heat exchanger on the boiling heat transfer performance of ammonia

In this study, ammonia boiling heat transfer coefficient and the overall heat transfer were measured in a plate evaporator for an ocean thermal energy conversion (OTEC) system using aluminum plates. The OTEC system used ammonia as the working and a plate heat exchanger (PHE) that combined titanium plates. In this study, we used an anodized aluminum herringbone plate with two chevron angles of 45 and 60° installed in a PHE and measured the boiling heat transfer coefficients of ammonia and overall heat transfer coefficients for both plates to compare their heat transfer performances. The experimental conditions included a hot water flow rate of 1 – 12 L/min, a working fluid mass flux of 7 – 30 kg/m2s, a hot water inlet temperature of 30 – 40 °C, and a system pressure of 700 kPa.It was observed that anodized aluminum can be used as a heat-transfer plate for the PHE. In addition, the maximum overall heat transfer coefficient of chevron angle of 45° was 4 kW/m2K, and that of 60° was 3.5 kW/m2K, respectively. The maximum ammonia boiling heat transfer coefficient of 45° was 12.5 kW/m2K, and that of 60° was 13 kW/m2K, respectively. The heat transfer coefficient values are similar. Additionally, the correlation between the nondimensional heat transfer and the Lockhart-Martinelli parameter of aluminum plates was also clarified for comparison with the previous ammonia plate heat transfer in a flat plate. By comparing the correlation equations, the aluminum plate exhibited a value twice that of the flat plate.

Treatment of heavy metal in the plating wastewater by electrocoagulation

Abstract This present paper evaluated a batch electrocoagulation (EC) scale containing two flat aluminium plate electrodes to treat total Cr, Zn2+ in real plating wastewater taken from CX Technology company. Response Surface Methodology (RSM) and Design-Expert 12 software were applied to optimize the operating conditions with three main factors including current density, pH, and retention time. The control experiments using FeSO4 10% were performed to compare with the electrocoagulation method. The best treatment efficiency occurred at a current density of 16.93 A/m2, pH 9, and a 31-minute reaction. The conductivity did not significantly affect to the total Cr and Zn2+ removal but reduced energy consumption. The jar-test experiment result was obvious the optimal factors of the coagulation-flocculation encompassing pH 10 and 3 ml/L FeSO4 10 %. The treatment efficiency of total Cr and Zn2+ were 97.22±0.3 % and 99.53± 0.006 %, higher than others. The generated sludge in the electrocoagulation method was 2,031± 0.91 g/L, equal to 51.7 % sludge of the coagulation-flocculation method. The treatment cost by electrocoagulation was less than others.

Evaluation of surface corrosion damage in thin plates by Zero-Group Velocity Lamb waves based on PVDF comb transducers

This paper introduces a novel method for assessing surface corrosion damage in thin plates by leveraging the high sensitivity of Zero-Group Velocity (ZGV) Lamb waves and the versatility of polyvinylidene fluoride (PVDF) comb transducers. Theoretical analyses of ZGV Lamb wave modes and their differentiation from thickness vibration modes were conducted. The functionality and utility of the PVDF comb transducer tailored for the specific S1-ZGV mode were assessed. Experimental findings demonstrate that the PVDF comb transducer efficiently excites and captures the S1-ZGV mode, enabling effective assessment of surface corrosion damage in thin aluminum plates. Compared to the variations in wave velocity of surface acoustic waves (SAW) and the S1-ZGV frequency, the spectral amplitude at the initial S1-ZGV frequency exhibits a monotonically decreasing trend with increasing corrosion levels, proving to be more sensitive and reliable for evaluating surface corrosion damage. This research offers theoretical underpinnings and experimental validation for damage assessment using ZGV Lamb waves with the PVDF comb transducer, showcasing significant potential for practical engineering applications.

Parity-Frequency-Space Elastic Spin Control of Wave Routing in Topological Phononic Circuits.

Topological phononic cavities, such as ring resonators with topological whispering gallery modes (TWGMs), offer a flexible platform for the realization of robust phononic circuits. However, the chiral mechanism governing TWGMs and their selective routing in integrated phononic circuits remain unclear. This work reveals, both experimentally and theoretically, that at a phononic topological interface, the elastic spin texture is intricately linked to, and can be explained through a knowledge of, the phonon eigenmodes inside each unit cell. Furthermore, for paired, counterpropagating TWGMs based on such interfaces in a waveguide resonator, this study demonstrates that the elastic spin exhibits locking at discrete frequencies. Backed up by theory, experiments on kHz TWGMs in thin honeycomb-lattice aluminum plates bored with clover-leaf shaped holes show that together with this spin-texture related angular-momentum locking mechanism at a single topological interface, there are triplicate parity-frequency-space selective wave routing mechanisms. In the future, these mechanisms can be harnessed for the versatile manipulation of elastic-spin based routing in phononic topological insulators.

Augmentation of pool boiling heat transfer using a microstructured aluminum surface fabricated by ultrasonic cavitation modification

Micro/nanostructure is a popular and effective structure for boiling heat transfer enhancement. In this study, ultrasonic cavitation modification is employed firstly to create microstructured aluminum surface for boiling heat transfer. With the impact of ultrasonic cavitation microjet, numerous micro pits and holes are formed on the surface in one step, constituting microstructures on aluminum plate. The saturated and subcooled pool boiling experiments are conducted at atmospheric pressure using ethanol as a working fluid. It is found that boiling hysteresis is apparent on the modified plate (MP) with the porous microstructure layer, which can be eliminated by periodically fluctuating heat flux. Under the stable saturated boiling condition, the maximum heat transfer coefficient is enhanced by 208% and wall superheat is decreased by 17.6 °C compared to the bare aluminum surface. Under subcooled boiling conditions, the boiling hysteresis on MP becomes weaker and the positive effect of microstructures on heat transfer performance is enhanced. The enhanced heat transfer coefficient of MP is mainly attributed to the increase of nucleation site density and further to the facilitation of bubble coalescence and departure, while the increased critical heat flux under subcooled boiling conditions is derived from the delaying occurrence of mushroom-like bubble.

Vibration and acoustic characteristics of aluminium-silicon carbide metal matrix composite plate under thermal environment

This paper investigates the vibration and acoustic characteristics of an aluminium-silicon carbide (Al-SiC) simply supported composite plate under thermal loads. The vibrational response induced by the temperature rise is analysed using Kirchhoff’s plate theory and the weighted integral (Galerkin) method. Additionally, the plate is acoustically modelled in conjunction with the air medium to investigate its acoustic response. The acoustic far-field radiation equation determines the plate’s sound pressure level (SPL). The findings reveal that the MMC I (65% SiC/A356.2 MMC SiC particulates reinforced, with three different sizes) plate exhibits a lower overall sound pressure level in the lower frequency range than other MMCs. Moreover, replacing the aluminium plate with the MMC I plate reduces the overall sound pressure level by 5.54 dB due to the high stiffness associated with the mixture of silicon carbide reinforcement in the aluminium matrix.

A Density Clustering RAPID Based on an Array-Compensated Damage Index for Quantitative Damage Diagnosis.

Guided wave array-based structural health monitoring (SHM) is a promising solution for diagnosing damage in metal-connected structures. In this field, the reconstruction algorithm for probabilistic inspection (RAPID) is one of the most widely used algorithms for performing damage localization. In this paper, a density clustering RAPID based on an array-compensated damage index is proposed. A new probability distribution function was constructed based on a new damage index, which is adaptive to different elements in the sensor array to compensate for performance variation. Then, the imaging matrix of the RAPID algorithm was density-clustered to obtain the location and degree of damage. Finally, the method was verified by experiments on a stiffened aluminum plate. The experimental results demonstrate that the method achieves damage localization and enables quantitative damage diagnosis.

Dynamics of water adsorption on SAPO-34: Comparison of three adsorbent bed configurations of adsorption chillers

Intensification of the adsorption dynamics is a strategic way to make adsorption chillers and heat pumps more competitive with conventional vapour compression systems. This can be achieved by consolidating the adsorbent bed with a heat exchanger to enhance heat transfer. This work investigates the dynamics of water adsorption on a commercial adsorbent SAPO-34 for three bed configurations, namely, a reference bed consisting of a monolayer of loose beads located on an aluminium plate, and two consolidated beds – a monolayer of beads glued to the plate, and a homogeneous coating of the plate prepared with binder. The morphology and texture of the prepared beds were studied by optical and scanning electron microscope techniques as well as by low temperature nitrogen adsorption. Six binders involved, both organic (hydroxyethyl cellulose, polyvinylpyrrolidone, polyaniline) and inorganic (heat-conductive compound CPTD, bentonite clay, colloidal silica sol), produced varying effects. It was found that the most preferred configuration involves SAPO beads glued to the plate with bentonite for which the heat transfer was enhanced by a factor of 1.2–1.7 while maintaining sufficient mass transfer. The effective heat transfer coefficient was measured for the most promising binders and selected configurations, and varied between 120 and 248 W/(m2 K). The heat transfer acceleration permitted the specific cooling power (at a conversion of 0.8) to increase from 2.7 kW/kg for loose beads of 0.8–0.9 mm size to 3.5 kW/kg for the same beads bound with bentonite. Thus, gluing pre-made commercial adsorbent beads with heat-exchanger with suitable binders presents a simple and promising method to enhance the adsorption dynamics, resulting in a more compact design of adsorption chillers.

A new method of magnetic pulse welding of dissimilar metal plates using a uniform pressure electromagnetic actuator based on pre-deformation

The magnetic pulse welding method using a uniform pressure electromagnetic actuator can effectively weld dissimilar metal plates. However, the existing uniform pressure welding method leads to serious thinning of the plate at the chamfer, lack of welding at the center, and bulging of the welded sample, which seriously affects the quality of the welded joint. To solve these problems and improve the quality of welded joints, a new uniform pressure welding method of dissimilar metal plates based on pre-deformation was developed in this work. In this study, using the welding of an AA1060 aluminum plate and an SS304 steel plate with a thickness of 1 mm as an example, it was confirmed through numerical simulation and experimental research that the pre-deformation of the flyer plate controlled the impact angle of the central area of the plate, and it effectively suppressed central non-welding and serious bulge issues. Further, the welding method also reduced the height of the cushion blocks on both sides, thus mitigating aluminum plate thinning at the chamfer, ultimately improving the tensile strength of the joint. Additionally, a microscopic observation showed that the welding interface formed a wavy composite interface, and the connection strength was good. This welding method can also be extended to welding other dissimilar metal plates.

Warpage control and interface characteristics of Ti/Al composite plates by differential temperatures rolling with mobile induction heating

This study addresses the issue of warping and low interfacial bonding strength in composite plates due to uncoordinated deformation during the rolling of titanium/aluminum composites. By adopting mobile induction heating with differential temperature rolling composite technology, heated titanium plates and room-temperature aluminum plates were successfully rolled into composites. The results show that when the titanium plate is heated to 500–900°C, the warpage of the titanium/aluminum composite plates first decreases and then increases, while the interface shear strength first increases and then decreases. It is particularly emphasized that the rolled composite plates is straight at 800°C, the Ti6O oxide layer formed on the titanium plate surface exhibits excellent adhesion to the substrate, while displaying susceptibility to cracks during the rolling process, allowing fresh aluminum metal to be squeezed into the cracks to form a mechanical mesh and an atomic bonding diffusion layer occurs due to the fresh metal contact between titanium and aluminum within the crack, thereby resulting in the composite plates exhibiting optimal shear strength. The findings verify the preliminary feasibility of the proposed novel rolling process and provide a novel solution for prepared titanium/aluminum composite plates, which is an important step for future fabrication and applications of composite plates.

Assessment of vitamins and minerals of rats fed with plantain-maize pudding prepared using edible plant leaves and metallic plates

Cooking materials are important factors that basically intended to provide covering, protection and consumers’ choice of food products. The objective of the study was to determine the vitamin profile and minerals in the serum of rats fed maize-plantain pudding cooked using different leaves and metallic plates. Different maize-plantain pudding samples were prepared using plantain and maize flour blended together 1:1 ratio. In the animal study, thirty rats were divided into six groups of five rats each. Rats in Group A served as control. Group B rats were given Tween 80. Rats in Groups C, D, E and F were fed pudding prepared using plantain leaves, ginger leaves, aluminium plates and cast iron plates respectively. The rats in each group were allowed free access to feed and clean drinking water throughout the period of the experiment for 28 days. Mineral analysis was done using an atomic absorption spectrophotometer. Vitamin profile was determined using high performance liquid chromatography (HPLC). The results showed that serum minerals (calcium, potassium, magnesium, sodium, iron and phosphorus) and total vitamin content were significantly higher in rats fed with pudding prepared using ginger leaves when compared with plantain leaves, cast iron plate and aluminium plate. The serum iron content was significantly higher in rats fed pudding prepared using cast iron plate compared to other groups. Therefore, the use of locally accessible and consumable leaves and cast iron plates or utensils may be encouraged in diet preparation

Utilization of coconut shell activated carbon to generate electrical energy using sodium chloride electrolyte

Fossil fuels that are used to generate electrical energy are running low. Besides that, energy generated from fossil fuels causes global warming and climate change due to gas emissions such as carbon dioxide, leading to a greenhouse effect. In addition, the development of small electronic devices has created power demands, from initially in milli watt (mW), to microwatt (μW) level for wireless sensor networks, which generally use batteries as a power supply. Therefore, environmentally friendly and renewable materials like coconut shells are needed to generate electrical energy. This research aims to generate electrical energy from a model using coconut shell activated carbon with sodium chloride (NaCl) electrolyte. The electrical energy generation model is composed of counter electrode–electrode–counter electrode. The electrode used was coconut shell–activated carbon. Three counter electrodes were used: aluminum, zinc and copper plates. The electrolyte used was sodium chloride (NaCl) solution. The electrolyte was injected between the electrode and the counter electrode, and heat was applied. When the electrolyte was injected into the electrical energy generation model, interaction occurred between the ions from the electrolyte and the functional groups, the pores of the activated carbon, and the counter electrode, and then electrons were released. The research results show that the voltage produced due to an increase in temperature up to ΔT=54 °C, is 0.875 volts for aluminum, 0.767 volts for zinc and 0.091 volts for copper. The average thermal voltage sensitivity (dV/dT) for aluminum is 68.99297 mV/°C, while that for zinc is 61.34319 mV/°C, and copper is 7.02533 mV/°C. The currents produced by aluminum, zinc and copper are 5.9 μA, 3.8 μA and 0.157 μA, respectively

3D liquid-based porous coating integrated with oleophilic MXene nanoflakes for durable ultra-low ice adhesion and exceptional photothermal slippery properties

The accumulation of ice on the surfaces of equipment/facilities can result in energy wastage, substantial economic losses, and even pose a threat to personal safety. In this work, a three-dimensional (3D) liquid-based porous resin coating doped with oleophilic molybdenum carbide (Mo2C) MXene nanoflakes was fabricated on a pre-coated oleogel sealer layer of aluminum plate. The results showed a reduction of approximately 99.1 % in ice adhesion strength (∼4.66 kPa) compared to the sandblasted aluminum plate and consistently maintained ice adhesion strength below 10 kPa for 70 days. Moreover, the coating exhibited excellent photothermal properties, with icing time delayed by a factor of 33.2 under simulated solar radiation power of 96 mW/cm2 (1 sun) at an ambient temperature of − 15 °C. The ice adhered to the coating could easily slide off without the external force under “1 sun” at − 10 °C. The superior anti/de-icing performance of the coating can be primarily attributed to the low interfacial modulus of the porous structure, the exceptional retention of silicone-oil, and the excellent photothermal effect of embedded MXene nanoflakes. The 3D liquid-based porous coating, possessing extremely low ice adhesion and remarkable de-icing stability, demonstrates the substantial potential for practical applications that require sustained anti/de-icing performance.

Classification of Time–Frequency Maps of Guided Waves Using Foreground Extraction

Guided waves propagating in mechanical structures have proved to be an essential technique for applications, such as structural health monitoring. However, it is a well-known problem that when using non-stationary guided wave signals, dispersion, and high-order vibrational modes are excited, it becomes cumbersome to detect and identify relevant information. A typical method for the characterization of these non-stationary signals is based on time–frequency (TF) mapping techniques. This method produces 2D images, allowing the study of specific vibration modes and their evolution over time. However, this approach has low resolution, increases the size of the data, and introduces redundant information, making it difficult to extract relevant features for their accurate identification and classification. This paper presents a method for identifying discontinuities by analyzing the data in the TF maps of Lamb wave signals. Singular Value Decomposition (SVD) for low-rank optimization and then perform foreground feature extraction on the maps were proposed. These foreground features are then analyzed using Principal Component Analysis (PCA). Unlike traditional PCA, which operates on vectorized images, our approach focuses on the correlation between coordinates within the maps. This modification enhances feature detection and enables the classification of discontinuities within the maps. To evaluate unsupervised clustering of the dimensionally reduced data obtained from PCA, we experimentally tested our method using broadband Lamb waves with various vibrational modes interacting with different types of discontinuity patterns in a thin aluminum plate. A Support Vector Machine (SVM) classifier was then implemented for classification. The results of the experimental data yielded good classification effectiveness within reasonably low computational time despite the large matrixes of the TF maps used.

Explore Ultrasonic-Induced Mechanoluminescent Solutions towards Realising Remote Structural Health Monitoring.

Ultrasonic guided waves, which are often generated and detected by piezoelectric transducers, are well established to monitor engineering structures. Wireless solutions are sought to eliminate cumbersome wire installation. This work proposes a method for remote ultrasonic-based structural health monitoring (SHM) using mechanoluminescence (ML). Propagating guided waves transmitted by a piezoelectric transducer attached to a structure induce elastic deformation that can be captured by elastico-ML. An ML coating composed of copper-doped zinc sulfide (ZnS:Cu) particles embedded in PVDF on a thin aluminium plate can be used to achieve the elastico-ML for the remote sensing of propagating guided waves. The simulation and experimental results indicated that a very high voltage would be required to reach the threshold pressure applied to the ML particles, which is about 1.5 MPa for ZnS particles. The high voltage was estimated to be 214 Vpp for surface waves and 750 Vpp for Lamb waves for the studied configuration. Several possible technical solutions are suggested for achieving ultrasonic-induced ML for future remote SHM systems.

Theoretical and experimental analysis of evaporative cooling with hydrophilic screen mesh on condenser surface

In this study, we theoretically and experimentally analyzed the effect of evaporative cooling on the external thermal resistance of a condenser with a water-filled hydrophilic screen mesh. To calculate the external thermal resistance of the condenser theoretically, the external thermal resistance model was developed, considering evaporative cooling in the screen mesh. The evaporative mass flow rate in the screen mesh was calculated using the Lewis number, which can convert heat transfer to mass transfer. Especially, the maximum flow rate absorbed by the screen mesh was theoretically determined by the capillary limit. In experimental approach, hydrophilic screen meshes with mesh numbers M100, M150, and M200 were manufactured and attached to an aluminum plate simulating the condenser surface. The external thermal resistance of the condenser was measured. Based on the results, the theoretical model was well matched with experimental results. The effects of the air velocity, mesh number, and heat flux on the external thermal resistance of the condenser with evaporative cooling in the water-filled hydrophilic screen mesh were investigated. Finally, it is shown that the external thermal resistance of the condenser with evaporative cooling using the water-filled hydrophilic screen mesh can be reduced up to an average of 92 %.

Surface pre-treatment of aluminum alloy for mechanical improvement of adhesive bonding by maple-assisted pulsed laser evaporation technique.

Adhesive joints are widely used for structural bonding in various industrial sectors. The performance of bonded joints is commonly attributed to the cleanliness of the substrate and the pre-treatment of the surfaces to be bonded. In this study, the Matrix Assisted Pulsed Laser Evaporation (MAPLE) deposition technique was used for surface modification of aluminum (Al) plates by the deposition of poly(propylene glycol) bis(2-aminopropyl ether) (PPG-NH2) of different number average molecular weights (Mn) of 400 g mol-1, 2000 g mol-1, and 4000 g mol-1, respectively. Fourier-transformed infrared spectroscopy (FT-IR) analysis indicated the characteristic peaks for the deposited layers of PPG-NH2 of different molecular weights in all cases while scanning electron microscopy (SEM) revealed continuous layers on the surface of Al plates. In order to demonstrate alterations in the wettability of Al substrates, a crucial aspect in surface treatment and adhesive bonding, measurements of contact angles, surface free energies (SFE), and adhesion work (W a) were conducted. The tensile strength measurements were performed using the lap-joint test after applying the commercial silyl-based polymer adhesive Bison Max Repair Extreme Adhesive®. It was evidenced that at higher values of the SFE and W a, the tensile strength was almost 3 times higher for PPG-NH2 with Mn = 4000 g mol-1 compared with the untreated Al sample. This study provides valuable insights into the successful application of the MAPLE technique as a pre-treatment method for reinforcing adhesive bonding of Al plates, which can lead to improved mechanical performance in various industrial applications.

Effects of area density of a hinged inertial cover on H2/CH4/air deflagrations in a vented chamber

Explosion venting is the most commonly used technique to reduce the hazard from accidental deflagration of combustible gases. Since less attention is paid to the influence of inertial vent on vented H2/CH4/air deflagration, the effects of area density (Ws) of a hinged inertial cover on the pressure profile and flame behavior during H2/CH4/air deflagration, with hydrogen volume fraction in fuel (χH2) being 0.5 and 0.8, were investigated by covering the vent using aluminum plates with various thicknesses. The results show that the interval between ignition and the moment the flame just travels through the vent (tout) is almost independent of Ws, but the opening angle of the panel at the time of tout is closely related to Ws. For a given χH2, the opening angle at the time of tout decreases with an increase in Ws. For a certain Ws, the opening angle of the panel is smaller for χH2 = 0.8 in comparison with the tests at χH2 = 0.5. In the test with higher Ws, the external fireball becomes more flattened. In tests at χH2 = 0.5, p3 induced by acoustic oscillations dominates the internal overpressure, but p2 resulting from the external explosion becomes the dominant pressure peak at χH2 = 0.8. The maximum reduced overpressure (pred) and maximum external overpressure (pext) are almost independent of Ws at χH2 = 0.5. However, in tests at χH2 = 0.8, pred and pext increase sharply with an increase in Ws from 0 kg/m2 to 2.7 kg/m2, but there is relatively little variation in pred and pext as Ws continues to increase from 2.7 kg/m2 to 24.3 kg/m2. Except for the test with Ws = 0 kg/m2, for a specific Ws, pred and pext at χH2 = 0.8 are always greater than those at χH2 = 0.5.

Thickness-dependent micro-fracture behaviors of pre-cracked aluminum plates by crystal plasticity finite element method and damage criteria

Despite the fact that fracture behaviors of pre-cracked metal plates were investigated by the crystal plasticity finite element method (CPFEM), the thickness effect on their micro-fracture behaviors is still not clear because of the different out-of-plane constraints. Here, mechanical properties and micro-fracture patterns of pre-cracked aluminum plates with different thicknesses are obtained by experiments, as well as by CPFEM combining with two damage criteria. First, finite element models are constructed based on grain morphologies of specimens achieved by electron back scattered diffraction experiments. Next, some key parameters required in CPFEM and two damage criteria are determined by fitting experimental stress–strain relationships. In particular, the factors affecting accuracy of FE predictions are clarified by CPFEM. Finally, thickness-dependent micro-fracture mechanisms of two different damage criteria in pre-cracked aluminum plates with various thicknesses and crack lengths are revealed by comparison with the experimental results and CPFEM. This investigation should be of great help for understanding thickness-dependent micro-fracture mechanisms of metal and other material plates.

Comparison between Mechanical Properties and Joint Performance of AA 2024-T351 Aluminum Alloy Welded by Friction Stir Welding, Metal Inert Gas and Tungsten Inert Gas Processes.

The aim of this work is to study joining Al 2024-T3 alloy plates with different welding procedures. Aluminum alloy AA 2024-T351 is especially used in the aerospace industry. Aluminum plates are welded by the TIG and MIG fusion welding process, as well as by the solid-state welding process, friction stir welding (FSW), which has recently become very important in aluminum and alloy welding. For welding AA2024-T35 with MIG and TIG fusion processes, the filler material ER 4043-AlSi5 was chosen because of reduced cracking. Different methods were used to evaluate the quality of the produced joints, including macro- and microstructure evaluation, in addition to hardness and tensile tests. The ultimate tensile strength (UTS) of the FSW sample was found to be 80% higher than that of MIG and TIG samples. The average hardness value of the weld zone of metal for the MIG- and TIG-produced AA2024-T3511 butt joints showed a significant decrease compared to the hardness of the base metal AA2024-T351 by 50%, while for FSW joints, in the nugget zone, the hardness is about 10% lower relative to the base metal AA2024-T3511.