Conical Copper Research Articles

Experimental investigation and visualization of steam condensation heat transfer on horizontal conical surfaces with microgrooves

ABSTRACT This paper presents a novel conical copper plate with microgrooves structure to enhance heat transfer by removing accumulated condensate in horizontal surface condensation. The experimental investigation focuses on the condensation occurring on horizontal conical plates under atmospheric pressure. Results show that the heat transfer performance of all conical grooved plates surpasses that of smooth plates. Increasing groove number enhances heat transfer coefficient while having negligible influence on pressure drop. In contrast, increasing top diameter leads to higher pressure drop values. The optimal surface heat transfer coefficient strengthening ratio reaches 1.58, providing valuable insights for future studies and practical engineering applications.

Preparation of a Bioinspired Conical Needle for Rapid Directional Water Transport and Efficient Fog Harvesting

Water shortages have become a serious issue that threatens the survival of humans, particularly in arid regions. Collecting fog from the air environment is an effective approach to obtaining freshwater resources. Herein, inspired by cactus spines, we fabricated a superhydrophilic conical copper needle by the combination of electrochemical etching and the SiO2 colloidal self-assembly method for water transportation and fog collection. It was found that a water film would be formed on the surface of the as-prepared copper needle once a water droplet was transported from the tip to the base, which acted as a lubricating film to reduce the frictional resistance between the following water droplets and the copper needle and promote the self-propelled movement of the droplets. As a result, the transport velocity and the longest transport distance of a single water droplet on the as-prepared copper needle were high up to 142 mm/s and 42 mm, respectively. Besides, the results reveal that the droplet transport distance decreased with the increase of apex angles, whereas it increased with the increase of droplet volume and tilt angles. Additionally, the as-prepared copper needle exhibited an outstanding water collection rate of ∼1700 mg/h for a single copper needle, which is five times that of the original copper needle. This work provides a facile and low-cost method to fabricate conical copper needles for water droplet manipulation and efficient fog collection, showing great application potential in the fields of microfluid, desalination, and freshwater collection.

Investigation of Cu metal nanoparticles with different morphologies to inhibit SARS-CoV-2 main protease and spike glycoprotein using Molecular Docking and Dynamics Simulation

Nowadays, considering the spread of the coronavirus as a global threat, scientific research on this virus through simulation has been increasing. In this study, effect of Cu nanocluster on prevention and control of disease transmission was examined using molecular docking and molecular dynamics simulation studies on the SARS-CoV-2 main protease and spike glycoprotein. The cytotoxicity of different shapes of copper NPs and resonance changes of their surface plasmons on inactivation of the coronavirus was examined in order to control replication of coronavirus through copper NPs, active site of protease and spike glycoprotein. The simulations results showed that interactions of SARS-CoV-2 main protease and spike glycoprotein target and cylindrical and conical copper NPs ligands were more efficient than spherical copper NPs.

A combined structural and wettability gradient surface for directional droplet transport and efficient fog collection

HypothesisThe droplet manipulation behavior is affected by chemical structural driving force (including the superposition of electric, magnetic, optical and thermal fields), which directly determine transportation velocity. A lot of research has focused on a single driving force that induces the directional transportation behavior, which affects its performance. ExperimentsA simple method for preparing wettability gradient conical copper needles (WGCCN) combining structural gradient and chemical gradient was formulated. The effect of droplet volume and tilt angles on droplet transport velocity was systematically studied. The process of droplet transport was revealed through theoretical model and mechanical analysis. Finally, the application of WGCCN and its array model in fog collection were explored. FindingsA continuous chemical gradient in the conical structure gradient induces the droplet directional transportation, and the transportation velocity depends on the droplet volume. In addition, under the cooperation effect of multiple driving force, the droplet can still be transported in a directional orientation even if it is tilted at a certain angle. The simple droplet manipulation behavior portends that the droplets directional transport behavior can be applied in microfluidic manipulation by cooperation of effective multiple driving force with satisfactory results.

Strategies for scaling-up LaNi5-based hydrogen storage system with internal conical fins and cooling tubes

Scaling-up of a 5 kg LaNi5 reactor i.e. Reference Design (RD) with 88.9 mm outer diameter (OD) and 10 conical copper fins embedded with 6 cooling tubes to a 25 kg one is studied through simulations. RD takes 585 s for 90% saturation during hydrogen absorption at Ps = 15 bar and 5 LPM water supply (20 °C). Decreasing tank OD and increasing the number of fins result in the best performance. A scaled-up design with tank OD = 114.3 mm and 60 fins exhibits 57–58% reduction in saturation time (695 s), versus a proportionally-scaled-up design (dimensions of RD increase proportionally) with tank OD = 141.3 mm and 10 fins. Five units of RD connected in series reduce saturation time by ~60% (670 s). Series/parallel configurations can match the RD performance, reduce shutdown risk, offer flexibility in operation, configuration and ease of maintenance.

The Role of Mass Transfer in the Rate of Electropolishing of Conical Copper Cavities under Natural Convection

The Role of Mass Transfer in the Rate of Electropolishing of Conical Copper Cavities under Natural Convection

Optimal Design of a Fog Collector: Unidirectional Water Transport on a System Integrated by Conical Copper Needles with Gradient Wettability and Hydrophilic Slippery Rough Surfaces.

Inspired by a cactus spine and pitcher plant slippery surface, a strategy is proposed to design a superhydrophobic-hydrophilic conical copper needle (SHB-HL CCN) and hydrophilic slippery rough surface (SRS) integrative system. In this strategy, the SHB-HL CCN was inserted vertically on the hydrophilic SRS, and such a hydrophilic SRS + SHB-HL CCN system exhibited a high-efficiency cycle in droplet capture-coalescence (supply)-transport during the fog collection process. Even with a single SHB-HL CCN or hydrophilic SRS, the water collection rate is much higher than that of the usual materials (original copper needle, superhydrophobic substrate, hydrophobic SRS, etc.). It is demonstrated that a newly enhanced fog harvesting mechanism and higher fog collection rate can be realized due to the synergy between the Laplace pressure difference from the conical needle, wettability force of wettability difference in the conical copper needles, and released surface energy in droplet coalescence in addition to the attracting force from water bridges formed between needles and substrate. Compared with a single SHB-HL CCN and hydrophilic SRS, the water collection rate of the hydrophilic SRS + SHB-HL CCN system increased by approximately 328 and 152%, respectively. This fog collector provides direction to design water harvesting systems, which has important promotion significance for water collection application engineering in industry, aerospace, and other fields.

One‐Piece Stainless‐Steel 3D Printed Minichannel Evaporators using Flow Boiling Carbon Dioxide

AbstractNew concepts are required for high‐performance minichannel evaporators with low mass and reduced size involved in the cooling of cylindrical or conical surfaces. The development of one‐piece stainless‐steel evaporators using flow boiling CO2 for the cooling of conical copper test specimens heated by a foil heater element is presented. The specimens mimic a mobile cooling device used in high‐energy and particle physics. The stainless‐steel evaporators were manufactured with a state‐of‐the‐art 3D stainless‐steel printer via selective laser melting. The computer‐aided design and the construction of this new type of evaporators are described. A dedicated two‐phase accumulator controlled loop filled with liquid CO2 was developed, it allowed for operating four parallel connected evaporators. Cooling efficiency and manufacture reproducibility were experimentally investigated by applying different thermal loads and refrigerant mass flows.

Modeling and numerical simulation of a 5 kg LaNi5-based hydrogen storage reactor with internal conical fins

Hydrogen absorption by ~5 kg LaNi5 in a metal hydride reactor is simulated. A cylindrical reactor (OD 88.9 mm, Sch- 40s, SS 316) with internal conical copper fins and cooling tubes (1/4”, SS 316) carrying water at 1 m s−1 and 293 K (inlet) is considered. Designs with 10, 13 and 19 equi-spaced fins and 2, 4 and 6 cooling tubes are explored. Hydrogen (15 atm) is supplied through a coaxial metal filter (OD 12 mm, SS 316). Conical fins offer enhanced heat transfer through higher surface area and funnelling effect for efficient loading of metal hydride powder. 19 fins + 6 tubes design requires 290 and 375 s for 80% and 90% hydrogen saturation level, respectively. The fins near the water inlet regions are more effective as the water temperature is lower in these regions. Trade-off exists between times taken for saturation and the mass of metal hydride.

Incipient spallation of high purity copper under non-one-dimensional strain shock waves

A new spallation experimental method by using conical target is proposed. Based on the analysis of wave propagation, the basic principle of spallation experiment of conical target is discussed. Then incipient spallation of high purity (HP) copper under non-one-dimensional strain shock wave is studied experimentally by using a gas gun setup. The damage distribution characteristics and micro-mechanism of conical HP copper target are analyzed. The intrinsic relationship between the characteristics of free surface velocity profiles and damage evolution is explored. The results indicate that 1) continuous damage zones including different damage states appear in the conical HP copper target with initial spallation from the bottom of cone to the top of cone along the direction parallel to the cone surface, which is attributed to the spatial evolution of the amplitude and duration time of tensile stress in the conical target; 2) quantitative statistical analysis of damage inside conical HP copper target reveals that the nucleation and early growth of micro-voids are random, while the coalescence of micro-voids has significant localization characteristics; 3) the normal free surface particle velocity profiles with typical pull-back spallation signals at different locations of conical HP copper target are measured by multi-channel photon Doppler velocimetry. Comparing with the damage distribution characteristics, it is revealed that the spallation strength based on pull-back velocity is independent of damage, and is the critical nucleation stress of micro-voids. But the slope and amplitude of pull-back rebound velocity depend on damage evolution process, which relates to the change of damage evolution rate and stress relaxation caused by damage degree respectively.

Enhanced Oil Spill Clean-Up Using Immersed Thermally Conductive Objects

A method for rapid burning of hazardous oil spills on water is investigated with the ultimate goal of designing a burner for faster clean-up of hazardous spills in offshore and other remote environments. A thermally conductive object, which comprises of a 0.25 cm thick copper porous mesh, with or without conical copper coils, is used. The influence of this object on the burning rate of an Alaska North Slope crude oil slick (1 cm thick) on saline water is studied. For the mesh-alone case, heat from flame is transferred to the mesh, which rapidly gets heated up and transmits the heat to the oil slick. This heat transfer is much higher than that in the baseline case. In the case with conical coils, which are engulfed in the flame, the heated up coils transfer the heat to the copper mesh more effectively. Thus, the object enhances the mass burning rate. Experimental results reveal that the copper mesh reaches a temperature higher than the boiling point of the oil, such that onset of nucleate boiling is possible. The mesh-coil system is able to burn thin slick of oil resting on water achieving an efficiency of ~ 400% above baseline. A simple integral model is also proposed to predict the temperature profiles in mesh, oil, and water layers. The predicted temperature profiles show good agreement with the experimental results. A parametric study using the integral model is also reported. The model can be used as a guideline to optimize the mesh porosity and thickness for different hazardous spill scenarios.

Fog collection on a conical copper wire: effect of fog flow velocity and surface morphology

The conical copper wires (CCWs) were subjected to alkali assistant oxidation or electrochemical deposition to form superhydrophilic wettability of ∼4° with needle-like or leaf-like morphology, respectively. The superhydrophobic CCWs with water contact angles of ∼156° were further constructed by modification with 1-dodecanethiol. The CCWs were used to study the effect of fog flow velocity and surface morphology on fog collection. With the fog flow velocity increased, the dominant factor for fog collection changed from fog capture to droplet motion. The surfaces with needle-like morphology displayed better fog capture ability while the surfaces with leaf-like morphology were more prone to driving droplet motion.

Phase selection and solidification path transition of Ti–48Al–xNb alloys with different cooling rates

Ti–48Al–xNb alloys were solidified by containerless electromagnetic levitation with quenching system of the conical copper mold. The influence of cooling rates on phase selection of Ti–48Al–xNb alloys was investigated. In near-equilibrium solidification condition, the dendrite β phase is observed as the leading phase. No other metastable phase (e.g., α phase) is observed. In contrast, in rapid solidification condition, the metastable α phase is observed in as-quenched Ti–48Al–2Nb alloy. Furthermore, the metastable α phase is replaced by the primary β phase with Nb addition increasing. For Ti–48Al–(x = 4, 6, 8)Nb alloys, increasing cooling rate results in a solidification path transition. The peritectic reaction (L + β → α) is therefore significantly suppressed. The relationships between primary dendrite arm spacing (λ1) and cooling rate (τ) can be described.

The effect of concrete damage on the penetration depth by the tandem projectiles

Tandem projectile is one approach of the development of anti-structure concrete projectile, which is made of the forward shape charge and the follow-through projectile. In this paper, in order to study the performance of anti-structure tandem projectiles, experimental and numerical analyses of the penetration process were performed for forward shape charge with conical copper liner hitting into the concrete targets. Having a well agreement, numerical and empirical results indicate that a forward shape charge with a conical copper liner will make appropriate tunnel diameter through the concrete targets. Following the validation of the applied numerical method, numerical simulations were conducted for the penetration of the follow-through projectile, by three different concrete targets: undamaged concrete, pre-drilled concrete, and damaged pre-drilled concrete. The parametric results show that the damaged pre-drilled concrete affects the penetration depth and residual velocity of the follow-through projectile significantly.

High-Efficiency Fog Collector: Water Unidirectional Transport on Heterogeneous Rough Conical Wires.

An artificial periodic roughness-gradient conical copper wire (PCCW) can be fabricated by inspiration from cactus spines and wet spider silks. PCCW can harvest fog on periodic points of the conical surface from air and transports the drops for a long distance without external force, which is attributed to dynamic as-released energy generated from drop deformation in drop coalescence, in addition to both gradients of geometric curve (inducing Laplace pressure) and periodic roughness (inducing surface energy difference). It is found that the ability of fog collection can be related to various tilt-angle wires, thus a fog collector with an array system of PCCWs is further designed to achieve a continuous process of efficient water collection. As a result, the effect of water collection on PCCWs is better than previous results. These findings are significant to develop and design materials with water collection and water transport for promising application in fogwater systems to ease the water crisis.

Effects of applied potential and the initial gap between electrodes on localized electrochemical deposition of micrometer copper columns.

Micrometer copper columns were fabricated via a technology named localized electrochemical deposition (LECD). This paper studies the effects of applied potential and the initial gap between electrodes on the LECD process. The surface and cross sectional morphologies, as well as the average deposition rate were investigated to evaluate the quality of the deposited copper columns. Results demonstrated that the copper columns tended to be cylinder-shape with few voids inside at lower potential (<2.4 V). Whereas,the copper columns tended to be dendriform-shape with lots of voids inside at larger potential (>2.8 V). The average deposition rate increased with the raise of potential. In addition, the copper columns tended to be cylinder-shape with the initial gap between electrodes to be 10 μm or below. However, the copper columns tended to be cone-shape when the initial gap between electrodes became larger (35 μm or above). The number of voids inside the copper column and the average deposition rate both decreased with the increase of the initial gap. Moreover, the process of LECD under varied electric field has also been simulated using COMSOL software, and the formation of cylindrical and conical copper columns was further explained based on the electric field distribution at the cathode.

Bio-Inspired Multistructured Conical Copper Wires for Highly Efficient Liquid Manipulation

Animal hairs are typical structured conical fibers ubiquitous in natural system that enable the manipulation of low viscosity liquid in a well-controlled manner, which serves as the fundamental structure in Chinese brush for ink delivery in a controllable manner. Here, drawing inspiration from these structure, we developed a dynamic electrochemical method that enables fabricating the anisotropic multiscale structured conical copper wire (SCCW) with controllable conicity and surface morphology. The as-prepared SCCW exhibits a unique ability for manipulating liquid with significantly high efficiency, and over 428 times greater than its own volume of liquid could be therefore operated. We propose that the boundary condition of the dynamic liquid balance behavior on conical fibers, namely, steady holding of liquid droplet at the tip region of the SCCW, makes it an excellent fibrous medium to manipulate liquid. Moreover, we demonstrate that the titling angle of the SCCW can also affect its efficiency of liquid manipulation by virtue of its mechanical rigidity, which is hardly realized by flexible natural hairs. We envision that the bio-inspired SCCW could give inspiration in designing materials and devices to manipulate liquid in a more controllable way and with high efficiency.

Numerical analysis of fluid structure interaction in water jet incremental sheet forming process using coupled Eulerian–Lagrangian approach

A coupled Eulerian–Lagrangian approach was used to simulate the whole deformation process of a water jet incremental sheet metal forming of a conical part by three dimensional finite element method. The Eulerian elements were used to model the water jet whereas the sheet and tools were simulated by the Lagrangian elements. The geometry of the work piece, thickness distribution,and surface pressure distribution, volume fraction of water in the Eulerian elements and the vectors of the water jet flow were studied by the finite element method. In addition, the relationship between bulging height, pump pressure and inclination angle of a deformed conical copper part by water jet incremental forming was approximated by an analytical method proposed by other researchers with a plane strain formulation and momentum theory of hydrodynamics. To verify the accuracy of the calculated results, the experiment of a water jet incremental sheet metal forming of an annealed copper sheet was carried out. It was shown that the numerical and also analytical results are generally in good agreement with experimental ones. In addition, It was found that the most of the thinning occurs in the former stage of water jet incremental forming and near the first path of the defined water jet trajectory, furthermore surface pressure is higher in the stagnation point whereas it is smaller than water pressure before injection from the nozzle of water jet.

An Application of Explosive Metal Forming in Military Field: The Relationship Between Shaped Charge Jet Formation and Thickness Variation Along Liner Length of Conical Copper Liner

Shaped charges are very convenient in the formation of very intensive local forces required for penetration and demolition of high strength targets, important in military area. It is generally used to penetrate armored vehicles such as tanks and to demolish concrete fortifications, fuel vessels and bridge constructions, in mining and geophysics, e.g., petroleum research for hard rock penetration and cutting, also in welding and demolition works in industry. In this study, effects of wall thickness variation of the conical copper (CU-OFHC) liner in model group T1 and T2 are investigated. Wall thickness variation is taken into account from the center of the apex to the circular base edge in model group T1 and from the circular base edge to the center of apex in model group T2. In this sense, the relation between the variable thickness, and the geometry and pressure of the jet is investigated. Obtained results are evaluated to determine the stand-off distance between the shaped charge and target which is most important in jet performance. Thickness variation along the liner length changes the liner wall cross-sectional area and increases the liner total mass at both the model groups. Hence, the similar behavior is expected in the two model groups. Hence, the results do not show such a similar behavior between the two model groups. Consequently, It can be said that the dominant parameter is geometrical change, not increase in total mass. This also means that the mass distribution in the liner is determinative parameter in jet formation.

Bioinspired Conical Copper Wire with Gradient Wettability for Continuous and Efficient Fog Collection

Inspired by the efficient fog collection on cactus spines, conical copper wires with gradient wettability are fabricated through gradient electrochemical corrosion and subsequent gradient chemical modification. These dual-gradient copper wires' fog-collection ability is demonstrated to be higher than that of conical copper wires with pure hydrophobic surfaces or pure hydrophilic surfaces, and the underlying mechanism is also analyzed.