Metal Tube Research Articles

Underwater electrical explosion of metallic wire and tube: A comparison study

With an initial energy storage of approximately 53.5 kJ, experiments on underwater electrical explosions of metallic wire and thin-wall tube were conducted. Two sets of controlled experiments were designed, and the wire and tube for each set were of the same length, cross-sectional area, and material. Load voltage, circuit current, and shock wave pressure were measured and analyzed, and electric power, energy deposition, and energy deposition rate were also calculated and investigated. Experimental results indicated that the underwater electrical tube explosion (UETE) always has higher and earlier local resistance peak, voltage peak, and electric power peak, as well as faster phase transition and ionization process than the underwater electrical wire explosion (UEWE). In addition, the energy deposition rate from the beginning of discharge or the decrease in current to the voltage peak is significantly increased when replacing a wire with a tube. For the shock-wave characteristics, the peak pressure, energy density, and impulse of the shock wave generated by UETE are greater than that generated by UEWE. The peak pressure at ∼33 cm increased from 21.1 to 24.5 MPa in the first set and from 18.1 to 21.7 MPa in the second when a tube was used instead of a wire. These experimental results help us understand the physical process of UETE and provide an alternative methodology for load design in industrial applications.

Co-Culture Device for in vitro High Throughput Analysis of Cancer-Associated Fibroblast and Cancer Cell Interactions

Introduction: Cancers in general, and specifically lung cancer, continue to have low patient survival rates when the patient is at an advanced stage when diagnosed. It appears that the local environment, especially fibroblasts and their signaling molecules, tends to induce metastasis, increase cancer cell resistance to treatment, and aid in tumor growth rates. Since 3-D models quickly become too complex and/or expensive and therefore rarely leave the lab they are developed in, it is interesting to develop a 2-D model that more closely mimics clustered tumor formation and bulk interaction with a surrounding fibroblast environment. Methods: In the present study, we utilize an off-the-shelf stereolithography 3-D printer, standard use well plates, magnets, and metallic tubes to create a customizable 2-D co-culture system capable of being analyzed quantitatively with staining and qualitatively with standard fluorescent/brightfield microscopy to determine cancer-fibroblast interactions while also being able to test chemotherapeutic drugs in a high-throughput manner with standard 96-well plates. Results: Comparisons from monoculture and co-culture growth rates show that the presence of fibroblasts allows for significantly increased growth rates for H460 cancer. Additionally, the viability of cancer cells can be quantified with simple cell staining methods, and morphology and cell-cell interactions can be observed and studied. Discussion: The high throughput model demonstrates that boundary condition changes can be observed between cancer cells and fibroblasts based upon the different chemotherapeutics that have been administered.

Numerical study of melting and solidification behavior of radial and linear cascaded metal foam latent heat storage shell and tube heat exchanger

Numerical study of melting and solidification behavior of radial and linear cascaded metal foam latent heat storage shell and tube heat exchanger

Effective Protective Coating of Pipe Metal with High-Strength Corrosion-Resistant Material Based on Low-Molecular Oligodiene

Statement of the problem. A significant number of PJSC «Gazprom» main gas pipelines were built thirty or more years ago. At that time ineffective insulating materials were used for protecting steel pipes, applied mainly in the conditions of the route, which led to their extremely unsatisfactory condition in the future. Thus, at present there is a need to develop effective protective coatings for steel pipelines using domestic materials and equipment. Results. As a result of a series of experiments the composition of the composite material of the insulating coating based on the rubber concrete (Kauton) optimized to the state of the rubber mastic of the usable consistency has been determined. By carrying out a series of search experiments, rational temperature-time regimes of rubber mastic heat treatment have been determined for the formation of an effective layer of protective coating on the surface of pipe metal isolating it from harmful influences. Experimental device for providing modes of structure formation of pipe metal insulating coating material has been designed. Vulcanization of the rubber-containing mastic on the surface of a steel tube is performed by induction heating of the tube metal maintaining the necessary temperature-time modes of structure formation of the protective coating material. The physical and mechanical characteristics of the insulating coating for steel pipes on the basis of rubber mastic have been determined experimentally. Conclusions. The results of the research allow us to draw a conclusion about expediency, efficiency and significance of application in various areas of industrial production of coatings based on synthetic rubber to protect steel pipes from various negative influences and aggressive environments.

Critical Review on Magnetically Impelled Arc Butt Welding: Challenges, Perspectives and Industrial Applications.

Magnetically Impelled Arc Butt (MIAB) welding is a cutting-edge joining method that replaces the conventional welding procedures such as resistance, friction, flash and butt welding. It is a solid-state process that uses a rotating arc to heat up the butt ends of tubes, being followed by a forging process that completes the joining of the workpieces The magnetic flux density and the current interact to develop the Lorentz force that impels the arc along the faying surfaces. This process is found to produce high tensile strength and defect-free welds in ferrous materials and for this reason, it is predominantly employed in automobile applications for joining metallic tubes. Also, this joining procedure can be applied in the fabrication of boilers, heat exchangers, furnace piping in petrochemical industry and other safety-critical high-pressure machinery parts. The MIAB method has several advantages such as a shorter welding cycle, lower input energy requirement and lower loss of material. Compared to other solid-state welding processes, the MIAB welding has an important advantage in terms of cost-efficient welds with better control and reliability. Moreover, there are researchers who have investigated the joining of non-ferrous dissimilar materials using this welding procedure. The studies have been focused on process parametric analysis that involves optimizing and forecasting the magnetic field and thermal profile distribution. This review article provides competitive insights into various design features, computational methods, tests and material characterization, technical issues and workarounds, as well as automation aspects related to the MIAB-welding process. This work will prove to be a quick reference for researchers, useful to identify the research gaps and conflicting ideas that can be further explored for advancements in joining the similar and dissimilar materials.

A multi-state fusion informer integrating transfer learning for metal tube bending early wrinkling prediction

Wrinkling is one of the most fatal defects of metal tube bending, which may seriously affect the forming quality and even lead to forming failure. Traditional wrinkling prediction methods fail to provide accurate results due to the complexity of multi-die coupling in the bending process and the neglect of time-varying effects. To this end, a novel early wrinkling prediction method is proposed in this paper, distinct from conventional methods, realizing to forecast future wrinkling trends during the bending process and laying the foundation for real-time wrinkling prediction. It leverages the wrinkling factor (WrF), calculated using the energy method, as temporal data during the bending process to indirectly predict future tube wrinkling trends. Since the wrinkling occurs at the beginning of the bending process, a multi-state informer-based early prediction of tube wrinkling is put forward utilizing the limited WrF collected at the start of the bending process. To meet the demand for high accuracy and efficiency of wrinkling early prediction in a dynamic process, the model pre-trained by the multi-state fusion wrinkling data from the fully bent tube is migrated to the target model through the transfer learning approach. A stainless-steel tube bending case is conducted as the verification experiment, which is simultaneously compared with the finite element analysis (FEA) result. The results show the superior prediction accuracy and higher efficiency of the proposed method mainly compared with the traditional Informer model, Transformer model, and Long Short-Term Memory (LSTM).

Forming characteristics of thin-walled tubes manufactured by free bending process-based nontangential rotation bending die

The free-bending process of a metal tube involves a geometric relationship between the eccentricity, the rotation angle of the bending die, the deformation zone length, and the bending radius. Ideally, during the forming process, the contact position between the bending die, and the outer bend of the tube remains tangent. However, due to factors such as the clearance of the bending die and material properties, the rotation angle can be adjusted within a specific range while still ensuring smooth tube formation. The tangential state is disrupted when the rotation angle changes, resulting in overbending or underbending. Thus, in this study, a new theoretical analysis of the free bending process, accounting for clearance, was developed to analyze the material flow and changes in the bending radius during the nontangential contact between the bending die and the tube. In addition, the reasons for achieving smooth tube bending even after adjusting the rotation angle were explained, and the deformation mechanism of the tube under the combined effects of additional tangential force from the bending die and axial propulsive force was analysed. Furthermore, the impact of the rotation angle on the bending radius and the displacement of the strain neutral layer (strain NL) was determined. Afterwards, finite element (FE) modeling and forming experiments were conducted to verify the proposed theoretical analysis under different deformation zone lengths and eccentricities conditions. Besides, the distribution of the inner and outer wall thicknesses of the tube under the nontangential rotation of the bending die was further analysed. The simulation and experimental results fit well with that obtained from theoretical analysis.

Dissimilar welding of UNS S31803 and UNS S30400 tubes superiority and adverse in rotary friction welding

Solid-state welding provides a distinct state of the art to joining various metal tubes. In contrast to other types of welding, dissimilar joining by solid-state welding maintains the integrity of its joints. Dissimilar joints of UNS S31803 and UNS S30400 tubes were carried out using rotary friction welding process. Three combinations of tube joints fabricated were, ASS to ASS, DSS to DSS and ASS to DSS joint. The tensile tests showed dissimilar weld joint achieved the minimum strength of ASS similar joint. Fractography for similar and dissimilar tube joints showed a ductile pattern of fracture with dimples and voids in the dissimilar tube weld. Microstructure analysis showed that diffusion bond line for similar and dissimilar joints confirms the sound weld tube joints. Corrosion test showed that among three combinations, ASS to DSS dissimilar joint had lesser corrosion rate than ASS to ASS or DSS to DSS similar joints.

Optimizing air distribution in floor and wall burners of an industrial steam cracking firebox: a CFD study

A 3D computational fluid dynamics model for an industrial scale steam cracking firebox is combined with a 1D reactor model for the cracking process within the reactor coil. This framework is validated using industrial tunable diode laser absorption spectroscopy (TDLAS) measurements in a naphtha steam cracking furnace. Industrial O2, H2O, CO and temperature data show good agreement with simulation results at different locations within the firebox. The influence of varying the primary-to-secondary air flow distribution to the floor and wall burners separately is investigated using the validated framework. Altering the primary-to-secondary air flow distribution of the floor burners from 75/25 to 25/75 results in a 66% increase in furnace run length and a 35% decrease in NOx formation. This shift in air ratio ensures a lower rollover height of the flame and a large recirculation zone of the flue gas, spreading the radiative heat flux on the reactor coil more evenly. Altering the primary-to-secondary air flow distribution of the sidewall burners from 50/50 to 100/0 results in a 13% increase in run length and a 30% decrease in NOx formation. More primary air towards the sidewall burners is found to lead to more evenly spread out flames along the wall, resulting in flame interactions between the different burners and a combined flow towards the center of the firebox. These interactions result in a more uniform tube metal temperature profile along the different passes of the coil.

Numerical and experimental investigation of pressure-controlled joule-heat forge welding of steel tubes

Joining metallic tubes without melting is an enroute to impermeable and high-strength joints for lightweight and transport applications. Friction-based joining processes avoid melting and solidification defects, although the generated metallurgical bonding remains critical due to the uncontrolled differential interface heating and plastic deformation. Pressure-controlled joule-heat forge welding obtains a joint in a solid state with uniform plastic deformation of faying interfaces. A short-duration high-current pulse is discharged across the metallic tube assembly under the electrically conducting copper-steel plates. A high-pressure contact and thermal softening allow a radially outward metal plastic flow with the expulsion of oxide films. The joint evolution is further controlled with the pushing rate to a set distance. This study marks the novel effort to examine the thin-walled steel tubes joining with an integrated experimental and numerical approach. The computational analysis based on the finite element approach reveals the time instants of the interfacial contact pressure, thermal softening, and plastic flow behavior for the joint formation. The welded and upset-out region indicates uniform recrystallization of radially aligned grains with a consistent microhardness distribution. The actual welded geometry dimensions matched fairly well with the calculated dimensions.

Impedance Variation in a Coaxial Coil Encircling a Metal Tube Adapter.

The impedance change in an induction coil surrounding a metal tube adapter is investigated using the truncated region eigenfunction expansion (TREE) method. The conventional TREE method is inapplicable to this problem as a consequence of the numerical overflow of the eigenfunctions of the air-metal multi-subdomain regions. The difficulty is surmounted by a normalization procedure for the numerical eigenfunctions obtained from the 1D finite element method (FEM). An efficient algorithm is devised by the Clenshaw-Curtis quadrature rule for integrals involving the numerical eigenfunctions. The numerical results of the TREE and FEM simulation coincide very well in all cases, and the efficiency of the proposed method is also confirmed.

Experimental investigation of the thermal performance of pervious concrete integrated with phase change material for dry cooling applications

While dry cooling systems excel in water conservation compared to wet cooling systems, their performance at high ambient temperatures remains subpar. This study explores a novel latent heat storage module, acting as a water-free pre-cooler to lower temperature of ambient air into the dry cooling system. Four module designs were constructed, based on a pervious concrete and a custom-made inorganic phase change material, calcium chloride hexahydrate, with stable latent heat over 1,000 freeze–thaw thermal cycles. This marks the first-time integration of inorganic phase change material into pervious concrete through micro- and macro-encapsulation. A forced-air heat transfer apparatus was used to evaluate the modules’ thermal performance and heat transfer characteristics, revealing substantial thermal capacity increases of the modules- from 20.0 to 49.2 kWh/m3 charging and 20.3 to 43.6 kWh/m3 in discharging. The module with highest heat storage capacity investigated in this work is the pervious concrete module with micro-encapsulated phase change material and cast around a metal tube array filled with phase change material, which consistently reduces temperature of the airflow at 35 °C and 0.86 m/s by an average of 2 ℃ over three hours, showing potential as a pre-cooler in dry cooling applications.

Numerical Investigation of the Effect of the Wall Properties on Downward Mercury Flow and Temperature Fluctuations in a Vertical Heated Pipe under a Transverse Magnetic Field

The work is motivated by the need to study the effect of abnormal quasi-periodic high-amplitude temperature fluctuations in a liquid metal flow in pipes and channels, which arise under conditions close to those specific for liquid metal (PbLi alloy, etc.) hydrodynamics and heat transfer in blankets of tokamak fusion reactors. Such temperature fluctuations in the cooling channels of the fusion reactor blanket pose a threat to the strength of the channel walls. The influence of the physical properties of the channel walls and potential fouling of their inner surface on the generation of these fluctuations has not been studied as yet. Therefore, this problem has been numerically investigated for a MHD mixed convection of a liquid metal in a round tube for a downward flow of mercury with the one-side heating condition under a strong transverse magnetic field using conjugate problem statement by the LES (Large Eddy Simulation) method. Numerical simulation was performed for four cases: (i) the effect of thermophysical and electrophysical properties of the steel pipe wall is neglected, (ii) the effect of wall material properties is included, (iii) the effect of the moderate contact electrical resistance caused by a layer of fouling deposits or oxides on the inner surface of the pipe is accounted for, and (iv) the resistance of the thin fouling layer is assumed to be very high. The predictions for the cases (i) and (iv) are in good agreement with the experimental data and the results of the direct numerical simulation. They demonstrate the existence of quasi-periodic abnormal high-amplitude temperature fluctuations in the fluid with a frequency of approximately 0.14 Hz. With a relatively low electrical resistance of the fouling film (case iii), the frequency of high-amplitude temperature fluctuations was considerably lower (0.07 Hz). In the absence of electrical contact resistance on the inner surface of the steel pipe (case ii), high-amplitude velocity and temperature fluctuations were not revealed in the fluid. Thus, it was shown for the first time that the physical properties of a wall and the electrical resistance between the fluid and the electrically conducting wall were responsible for the development of abnormal temperature fluctuations in the liquid and the wall and control of their amplitude and frequency. The causes of the revealed effects are discussed.

Design and modular scale-up of shell and tube metal hydride hydrogen storage reactor utilizing multi-pass water flow

Shell-and-tube designs with multi-pass fluid flow are not used for metal hydride hydrogen storage reactors. Here, the absorption performances of reactors having shell outer diameter [OD]: 114.3, 141.3 and 168.3 mm with 36, 60 and 92 tubes arranged in 3, 4 and 5 circular arrays housing 25 kg LaNi5 at 20 bar hydrogen pressure, 10 LPM water entering at 30 °C are simulated. Considering the trade-off between tube volume and reaction duration, OD: 141.3 mm, 60 tubes offers a balanced performance with 90% absorption taking ∼320 s with four water passes (4-pass-scheme) vis-à-vis ∼380 s with one pass (1-pass-scheme). This design is scaled-up to house 100 kg LaNi5 with four modules in series and parallel configurations. When in series, reactors take 320, 425, 545, and 665 s for 90% absorption; in parallel, each reactor takes 625 s. At higher water flow rate (40 LPM) series and parallel configurations perform similarly.

Comparison of shear bond strength and residual adhesive remnants on the enamel surface after debonding of three different orthodontic molar tubes : Ascanning electron microscope study.

The aim for this research was to evaluate and compare the impact, bond strength, and residual adhesive on the enamel surface after debonding of different orthodontic molar tubes. The tested materials were metal, composite, and newly introduced ceramic orthodontic molar tubes. In all, 66first molar teeth were randomly divided into three groups. Metal, glass-fiber composite and ceramic orthodontic molar tubes were bonded and shear bond strength (SBS) tests were performed. The adhesive remnant index (ARI) scores after debonding were recorded and the enamel surfaces were investigated using scanning electron microscopy (SEM) after the adhesives were cleaned. The mean SBS values of the metal and ceramic tube groups were significantly higher than that of the glass-fiber composite tube group. The highest SBS values were recorded for the ceramic tube group (11.09 ± 2.51 MPa). Failure typically occurred at the adhesive-enamel interface in the ceramic group, whereas the majority of the samples in the glass-fiber composite group showed failure at the adhesive-tube base interface according to ARI and SEM investigations. ARI1 and ARI2 scores were commonly observed for the metal tube group. All the molar tubes tested had generated clinically acceptable SBS values; however, the values for glass-fiber composite molar tubes were significantly lower than those for the ceramic and metal molar tubes. If the debonding procedure is performed carefully, the ceramic molar tubes may be an enamel-safe product for patients seeking fully esthetic orthodontic treatment.

Proposal of a new mechanism of ammonia on the coking inhibition of n-decane under supercritical conditions

The coking problem of hydrocarbon fuel pyrolysis is the key factor affecting the application of active cooling technology for high-speed aircraft. The purpose of this work is to investigate the coking inhibition performance and coking mechanism of using ammonia as an additive during the thermal cracking. In this study, the pyrolysis and coking characteristics of supercritical n-decane were experimentally studied using an electrically heated tube. ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer), GC–MS (Gas Chromatograph Mass Spectrometer), SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectroscopy), TPO (Temperature Programmed Oxidation), and Raman spectroscopy are applied to characterize the anti-coking performance of the additives. The results show that the additive hardly affects the cracking of the fuel under high-temperature conditions, but the coke mass deposited on the inner surface of the tube is significantly reduced, and the coking inhibition rate can reach 80% at 750 °C. The addition of additives reduced the graphitization degree and oxidative activity of the coke. The maximum oxidation temperature of the coke obtained at 750 °C was reduced by 145 °C, and the ID/IG value of the Raman spectroscopy peak-fitting was 3.29. The new mechanism of the effect of additives on the formation of coking precursors and the deposition of coke on the surface of the tube wall is proposed. Ammonia can react with Ni of the inner metal tube and radicals generated by fuel cracking to form a carbonized film, achieving the effect of inhibiting metal catalytic coking. Meanwhile, the amino radicals generated by ammonia dehydrogenation can regulate the coking reaction path by forming a stable p-π conjugate structure with unsaturated radicals. Therefore, the research will contribute to a deeper comprehension of the coking inhibition mechanism and the development of more effective coking inhibitors, providing new technical support for active cooling technologies.

Bubble behaviour and critical heat flux investigations on electrodeposited metallic tubes during pool boiling

There is colossal research scope in achieving greater functionality and durability in microelectronic devices as conventional air cooling systems cannot handle these devices' cooling requirements which may be due to their low heat transfer performance. In such instances, phase change heat transfer mechanisms are appropriate for heat extraction since they utilise both sensible and latent heat. The ability to remove huge amount of heat at low wall superheats and the lack of moving parts make pool boiling appealing. This experimental study emphasises the analysis of bubble behaviour and critical heat flux (CHF) on electrodeposited tubes developed via in-house built set-up. Copper has been deposited over SS 304 tubes of a length of 100 mm and diameter of 2.5–4.5 mm. Their surface morphologies have been investigated using various characterization techniques such as SEM, EDS, AFM, and XRD. The surface roughness measurement confirms that electrodeposition increases the roughness of the tube. The contact angle analysis confirms that the coated surfaces are hydrophobic in nature. The CHF visualization is carried out under uniform heat flux conditions. It is observed that with an increase in diameter, the magnitude of CHF reduces irrespective of the coated and uncoated surface. The hydrophobic surface exhibits a lesser CHF magnitude than the uncoated surface. The reduction in CHF magnitude is within a range of 4.27%–8.93%. At lower heat flux magnitude, the bubble nucleation is rigorous in coated tubes, making it efficient for phase change heat transfer applications.

Cross-sectional performance prediction of metal tubes bending with tangential variable boosting based on parameters-weight-adaptive CNN

Metal bending tubes have been widely used in various fields owing to their excellent performance; however, bending defects significantly affect their quality. This study proposes a tangential variable boosting (TVB) scheme to reduce the severity of multiple defects generated during the rotary draw bending (RDB). The boosting pressure die is divided into several parts. Different process parameters were applied to the divided semi-parts based on the tangential stress distribution trend. To explore the effects of the TVB, a cross-sectional defect prediction method is proposed based on a parameter-weight-adaptive convolutional neural network (PWA-CNN). To validate the proposed prediction method, a dataset for training the prediction model was constructed using a series of numerical simulations of aluminum-alloy tubes. The prediction results of the PWA-CNN were then compared with those of the other CNNs and different weight assignment methods. The comparison results show that the PWA-CNN exhibits the best performance in predicting the tube cross-sectional distortion. Finally, the effects of the TVB on the forming quality of the bending tubes were obtained. A reasonable TVB is beneficial for reducing the wall-thinning and contour distortion ratios of the tubes and has a negligible effect on the short-axis variation rate.

Bo-LSTM based cross-sectional profile sequence progressive prediction method for metal tube rotate draw bending

Predicting the cross-sectional profile of the whole bending segment for metal tube bending is essential to achieve high-precision bending, yet still remains challenging. The existing prediction methods mainly base on theoretical derivation under certain assumptions and approximations, which do not fully characterize the whole bending segment profile neither do they fully utilize the information in the bending process. In this study, a Bo-LSTM-based progressive prediction method for the cross-sectional profile sequence is proposed, which comprehensively utilizes the profile information during the bending process and achieves an accurate prediction of the cross-sectional profile of the whole bending segment in the subsequent bending process. Firstly, the method of describing the cross-sectional profile in polar radial vector and the cross-sections of the bending segment in discrete sequences are proposed, which cover the information of cross-sectional distortion and wall thickness variation (viz. cross-sectional defects) for the whole bending segment. Secondly, an LSTM network is constructed integrating Bayesian-optimization-based hyper-parameters selection approach to progressively predict the tube cross-sectional profile sequence. Finally, the proposed methods are verified on simulated datasets as well as experimental data, and the accuracy is compared with networks of different structures. The results show that Bo-LSTM has better prediction accuracy. Meanwhile, the progressive prediction pattern has better robustness compared to chain prediction pattern.

Mechanism of oxide film removal and analysis of diffusion behavior of interfacial elements during magnetic pulse-assisted semi-solid brazing

The magnetic pulse-assisted semi-solid brazing (MPASSB) for Cu/Al tubes is proposed, in order to effectively remove oxide film to ensure the metallurgical bonding of Cu/Al brazing and joint performance. By designing a field shaper with a specific taper angle, the axial distribution of the electromagnetic force, tube deformation, and filler metal shear rheology are controlled to obtain the interface joining characteristics under different mechanical conditions. The relationship between the deformation behavior of the tube and filler metal with the interface element diffusion and metallurgical bonding is analyzed through the forming process simulation and interface microscopic characterization. In addition, the mechanical mechanism of oxide film removal is discussed as well. The results show that metallurgical bonding and element diffusion depend on the comprehensive effect of the interface compressive stress and the shear rheology of the filler metal. The larger the compressive stress, the better the oxide film removal. The stress at the bottom Cu/filler metal interface is the weakest, with an oxide layer thickness of 11.5 µm. The higher the shear rheological rate, the less the element diffusion depth. The filler metal flow rate at the bottom Cu/filler metal interface is the slowest, with a maximum depth of element diffusion of 13.5 µm. On the premise of ensuring the effective removal of the oxide film, the shear rheological rate (compressive stress) should not be too high.