Tube Liner Research Articles

Buckle propagation in confined steel tubes

It is well known that tubular liners of stiff cavities such as grouted oil-well casing can be collapsed by external pressure. Collapse is initially local but can propagate at a relatively low pressure with catastrophic results. The paper presents a quantitative study of the lowest pressure at which confined collapse can propagate known as confined propagation pressure. Experiments and analysis are used to develop an improved expression relating this critical pressure to the material and geometric parameters of the liner tube. It is shown that these include the yield stress and post-yield characteristics of the material, and the tube D/ t. The new empirical relationship developed can provide engineering type estimates of the confined propagation pressure. The quasi-static initiation and propagation of confined collapse was also modeled using three-dimentional finite elements. The model accounts for the finite deformations and addresses the contact nonlinearities which govern the phenomenon. The material is modeled as a finitely deforming elastic–plastic solid. It is demonstrated that the model can predict the confined propagation pressure to a very significant degree of accuracy. It is thus a viable tool for obtaining accurate predictions of this critical pressure.

溶接用ワイヤの送給性に関する考察

Feedability of welding wire is controlled by sliding contacts between contact tube and wire surface. It is very important for the stable arc discharge that feeding speed of wire does not deviate from the constant speed derived from average welding current. Temperature of contact tube, current branch, voltage drop, and contact resistance of the sliding contact were measured during welding of Cu-coated and non-Cu-coated solid wires. The sliding contacts of Cu-coated solid wire have both states of solid and liquid depending on welding current. On the other hand, the sliding contacts of non-Cu-coated solid wire have a state of liquid without depending on welding current. Discontinuity of solidification at the sliding contacts causes feeding resistance of welding wire. Shearing strength of bridge solidified at sliding contact is about 4.5N, and this force is amplified in liner tube to about ten times. The amplified force is feeding resistance of welding wire. Deviation of wire speed is 43% to average wire speed assuming spring constant of welding wire to be 6600N/m.

Modeling of thermally sprayed coatings on light metal substrates: ? layer growth and residual stress formation

Automotive lightweight engineering is indispensable for fuel saving and reduction of emissions. The substitution of cast iron engine blocks by light metal components yields significant weight savings. Thereby, protective coatings, which can be applied by thermal spraying, are essential for cylinder liner surfaces to resist mechanical and tribological load during operation of the internal combustion engine. Aluminum alloys and ceramic coating materials show a principal mismatch in their thermophysical and mechanical properties. Due to the fast and dynamic heat and mass transfer processes during thermal spraying this leads to the formation of residual stresses in the layer composite. Hence, residual stress analysis and understanding their generation mechanisms are essential for the optimization of the manufacturing process and for the operational reliability of the component. Numerical finite element analysis (FEA) provides the facility to examine stress formation in real-time depending on temporary heat distribution in the component during the manufacturing process. A cylinder liner tube is modeled and an inside coating process with continuous material deposition is simulated. To analyze the influence of heat transfer manipulation during manufacturing, different simultaneous cooling techniques are adopted to the model. Finally, FEA results are verified (or supplemented) by measurements with the microhole drilling and milling method. Combined, this yields a deeper understanding of residual stress formation and a tool for an effective optimization of thermal spray processes.

Modeling of thermally sprayed coatings on light metal substrates: – layer growth and residual stress formation

Automotive lightweight engineering is indispensable for fuel saving and reduction of emissions. The substitution of cast iron engine blocks by light metal components yields significant weight savings. Thereby, protective coatings, which can be applied by thermal spraying, are essential for cylinder liner surfaces to resist mechanical and tribological load during operation of the internal combustion engine. Aluminum alloys and ceramic coating materials show a principal mismatch in their thermophysical and mechanical properties. Due to the fast and dynamic heat and mass transfer processes during thermal spraying this leads to the formation of residual stresses in the layer composite. Hence, residual stress analysis and understanding their generation mechanisms are essential for the optimization of the manufacturing process and for the operational reliability of the component. Numerical finite element analysis (FEA) provides the facility to examine stress formation in real-time depending on temporary heat distribution in the component during the manufacturing process. A cylinder liner tube is modeled and an inside coating process with continuous material deposition is simulated. To analyze the influence of heat transfer manipulation during manufacturing, different simultaneous cooling techniques are adopted to the model. Finally, FEA results are verified (or supplemented) by measurements with the microhole drilling and milling method. Combined, this yields a deeper understanding of residual stress formation and a tool for an effective optimization of thermal spray processes.

New high-performance cryofocalizer injector for in-tube solid-phase microextraction and headspace capillary gas chromatographic applications

The construction of a high-efficiency but cheap injector for volatile and very volatile compounds is shown. The device focuses the compounds in a fused-silica (FS) transfer capillary with the aid of liquid nitrogen. A 6.2 mm O.D. glass tube liner (ca. 25 cm ×1.5 mm I.D.) is inserted in the heated (∼200 °C) injector of the gas chromatograph in place of the standard glass liner, and extends further externally through a liquid nitrogen container made with styrofoam-like material. Inside this glass tube, the FS transfer line passing through the oven door is connected like a pre-column to the analytical high-resolution GC column. It can move fast between the heated and the cooled zone (↔, ΔL=13 cm), and when this movement starts, cryofocused analytes are injected “at once” resulting in symmetrical and sharp injection bands with “zero” carryover. The performance of this device is demonstrated by its application to in-tube solid-phase microextraction and to spice volatiles analysis.

Design and experiment of hot gas duct for the HTR-10

A horizontal coaxial double-tube hot gas duct is a key component connecting the reactor pressure vessel and the steam generator pressure vessel for the 10 MW High Temperature Gas-cooled Reactor—Test Module. Hot helium gas from the core outlet flows into the steam generator through the liner tube, while helium gas after being cooled returns to the core through a passage formed between the inner tube and the duct pressure vessel. Thermal insulation material is packed into the space between the liner tube and the inner tube to resist heat transfer from the hot helium to the cold helium. The thermal compensation structure is designed in order to avoid large thermal stress because of different thermal expansions of the duct parts under various conditions. According to the design principal of the hot gas duct, the detailed structure design and strength evaluation for it has been done. A full-scale duct test section was then made according to the design parameters, and its thermal performance experiment was carried out in a helium test loop. With helium gas at pressure of about 3.0 MPa and a temperature over 900 °C, the continuous operation time for the duct test section lasted 98 h. At a helium gas temperature over 700 °C, the cumulative operation time for the duct test section reached 350 h. The duct test section also experienced 20 pressure cycles in the pressure range of 0.1–3.4 MPa, 18 temperature cycles in the temperature range of 100–950 °C. Thermal test results show an effective thermal conductivity of the hot gas duct thermal insulation is 0.47 W m −1 °C −1 under normal operation condition. In addition, a hot gas duct depressurization test was carried out; the test result showed that the pressure variation occurred on the liner tube was not more than 0.2 MPa for an assumed maximum gas release rate.

日本近海の長尺ピストンコアに見いだされたスープ状擾乱層

Soupy disturbances appeared in the long piston cores taken from the Oki Ridge, off Shiretoko, off Kashima and off Kochi during IMAGES Vil-WEPAMA Leg 2 (May-June 2001). The soupy disturbance layers were cold when the core was recovered, and they expelled the mixture of gas, water and mud through drilled holes of the core liner tube. This suggests the dissociation of gas hydrates in the core onboard. Because the presence of soupy disturbance does not prove the existence of gas hydrate by itself, we need to obtain additional evidences in a future long piston coring study.

Mass spectrometry study during the vapor deposition of poly-para-xylylene thin films

A differentially pumped quadrupole mass spectrometer was used to analyze the vapor species present in the deposition chamber during the vapor deposition of poly-para-xylylene (parylene) thin films. The partial pressure in the deposition chamber of volatile contamination originating in the dimer source, di-para-xylylene, was determined. The solvents xylene and acetone, as well as water, were determined to be the main contaminants. Fragmentation patterns of the monomer and dimer were gathered and the composition of the main peaks in each pattern was determined. The largest peak was 104 atomic units (amu) in the monomer pattern and 103 amu in the dimer pattern. The quantitative conversion of dimer to monomer was studied as a function of the pyrolysis furnace temperature from 345 to 665 °C for pyrolysis tube liners of quartz, copper, and nickel. It was found that conversion begins at around 385 °C, and by 565 °C 100% of the dimer flowing through the pyrolysis zone is converted (or cracked) into the monomer.

A Three-dimensional Study Of The Heat And Mass Transfer WithinThe Irradiation Space Of The HIFAR Fuel Element

A three-dimensional mathematical model for the HIFAR fuel element is described. The thermal-hydraulics behaviour within the irradiation space in the fuel element has been investigated. Effective cooling of the target cans could be obtained from the current operational settings. Complex flow structures were observed in the liner and support tube nose cones area. Large temperature gradients were found across the UO] pellets and MgO powder. The predicted central temperature in the UO] pellets was 2550 K. Maximum surface temperatures on the outer wall of the target cans were found to be 370 K for the first can and 380 K for the second can respectively. These values were comparable with experimental measurements and within the normal operating limits.

Analytic and numerical analysis of the longitudinal coupling impedance of a rectangular slot in a thin coaxial liner

Beam pipes of high-energy superconducting colliders require a shielding tube (liner) with pumping slots to screen cold chamber walls from synchrotron radiation. Pumping slots in the liner walls are required to keep high vacuum inside the beam pipe and provide for a long beam lifetime. As previously discussed [Fedotov and Gluckstern, Phys. Rev. E 54, 1930 (1996)], for a long narrow slot whose length may be comparable with the wavelength, the usual static approximation for the polarizability and susceptibility that enter into the impedance is a poor one. Therefore, finding semianalytic expressions for the impedance of a rectangular slot in a broad frequency range is highly desirable. We develop a general analysis based on a variational formulation, which includes both the realistic coaxial structure of the beam-pipe and the effect of finite wavelength, in order to calculate the coupling impedance of a rectangular slot in a liner wall of zero thickness. We then present a numerical study of the frequency dependence of the coupling impedance of a transverse rectangular slot. Numerical results for a small square hole are presented for frequencies above and below cutoff, and compared with the results of other calculations.

Effects of the solid-solid interface on the thermal behavior of deuterium in zircaloy cladding tubes

Using nuclear reaction analysis (NRA), experimental studies on diffusion and absorption of hydrogen isotopes in zircaloy were conducted. These thermal behaviors would be influenced by solid-solid interfaces such as zirconium-zircaloy in liner tubes of nuclear fuel elements and impurity-zircaloy on the cladding surfaces. A specimen of Zr-liner Zircaloy-2 cladding was thermally charged with deuterium gas and slowly cooled in the gas. NRA showed that deuterium highly accumulated in the side of zirconium near the interface, and the deuterium concentration in Zircaloy-2 became lower. This indicated that the deuterium redistribution occurred due to the deuterium migration toward the Zr-liner during slow cooling. This redistribution may be explained by a slight difference of temperature dependence of the terminal solubility of deuterium between zirconium and Zircaloy-2. The observed profile of deuterium may suggest the distribution of tritium in stored spent fuel claddings. Another experiment was to observe the deuterium concentration in Zircaloy-4 tubes, of which impurity elements were present on the surface. Before sample specimens were charged with deuterium gas, nickel or iron was deposited in vacuum, mechanically rubbed, or implanted to them. It was found that effects of the impurity-zircaloy interface much depended on the way of impurity charging.

Photon desorption measurements of copper and copper plated beam tubes for the SSCL 20 TeV proton collider

Relativistic protons circulating in the SSCL 20 TeV collider emit synchrotron radiation (1016 photons/m/s, Ecrit=284 eV). This radiation will photodesorb gases from the walls of the beam tube. The 4.2 K superconducting magnet bore tubes will act as very long distributed pumps. Build up of cryosorbed gases could severely limit collider operation and may require a bore tube liner to hide cryosorbed molecules from the photon flux and to increase the H2 pumping capacity. To predict collider vacuum performance, photon stimulated desorption experiments have been running at the National Synchrotron Light Source (NSLS) at BNL and on the VEPP2M storage ring at BINP, Novosibirsk, Russia. At the U10B beamline of the VUV ring at NSLS, beam tube samples were exposed to over 1023 photons/m with Ecrit=486 eV and incident angle=12 mrad. Unbaked copper and copper plated stainless steel have been tested. In addition, results have been obtained with a 1100 G dipole magnetic field and with a 350 °C vacuum bake. Results are presented and compared with other measurements at the NSLS and at other laboratories.

Restraint of Whirl Vibration in the Draft Tube by Air Admission and by Fins.

This paper presents experimental studies for two techniques by which restrain whirl vibration in a draft tube which occurs under partial load operation of Francis-type water turbines. One is to admit air into the draft tube and the other is to attach fins on the upper draft tube liner. Tests are performed using a model turbine of 176(m-kW) in specific speed and 355. 6mm in discharge diameter. The results are that the air admission always effectively restrains the amplitude of the pressure fluctuation for the high-frequency components, while for the low-frequency components it restrains the pressure amplitude only in the low cavitation number range. Also, in the a high cavitation number range, it unexpectedly magnifies the pressure amplitude, and fins restrain the low-frequency pressure amplitude throughout the whole cavitation number range.

Analysis of Bimetallic Pipe for Sour Service

Summary This paper presents the results of laboratory investigations conducted to better our definition of the serviceability of bimetallic pipe manufactured by the thermohydraulic (tight-fit) method for Mobile Bay service. Both Alloy 625/API X-65 and Alloy 825/API X-65 tight-fit pipe (TFP) were evaluated under conditions of (1) standard corrosion test environments to evaluate the metallurgical conditions of the corrosion-resistant-alloy (CRA) liner tubes, (2) long-term, full-scale TFP exposure under a simulated Mobile Bay production environment containing high levels of H2S and CO2, and (3) hydrogen-permeation experiments designed to examine potential effects of CRA liner collapse from hydrogen produced by corrosion on the ID and/or cathodic protection on the OD. Results indicate that bimetallic TFP exhibited an acceptable metallurgical condition of the CRA liner materials. Under the simulated Mobile Bay production environment, TFP exhibited good resistance to general corrosion, stress-corrosion cracking (SCC), and liner collapse. Hydrogen-permeation tests indicate that very conservative estimates of service-life liner collapse from interfacial hydrogen pressure range from 150 to more than 800 years, depending on conditions. For all practical purposes, liner collapse from hydrogen is not a limiting factor for TFP flowline applications.

MOVPE of In(GaAs)P/InGaAs MQW structures

Abstract We report on MOVPE growth of In(GaAs)P/InGaAs multi-quantum-well (MQW) structures. The growth was carried out at a reactor pressure of 20 hPa in an horizontal lamp heated cold wall reactor with rectangular inner liner tube using as group III elements TMIn and TMGa and as group V elements 100% AsH3 and PH3. Wedge transmission electron microscopy (WTEM), photoluminescence (PL) measurements at 2K and 300 K, and X-ray double crystal diffractometry (DCD) were used for characterization. WTEM technique demonstrates monolayer interfaces and an excellent periodicity of the structures. This is in addition proven by DCD measurements with satellite peaks up to the 8th order. Separate confinement MQW (SCMQW) laser structures with InGaAsP barriers were grown and fabricated to Broad Area (BA) lasers. As a best value we measured threshold current densities of 800 A/cm2. A graded refractive index separate confinement heterostructure (GRINSCH) MQW laser structure with 7 InGaAsP grading layers was also grown and showed very homogeneous laser results with a 20% increased quantum efficiency as compared to SCMQW structures.

Implosion Strength of Liner Tube on Double Wall Pipe

Implosion Strength of Liner Tube on Double Wall Pipe

Corrosion Behavior of Zirconia-Coated Hastelloy X in a High-Temperature Helium Environment

Abstract The corrosion behavior of Hastelloy X coated with (NiCrAl)/(ZrO2-CaC2) was examined, after serving as the liner tube of helium engineering demonstration loop (HENDEL) hot gas duct. The Has...

Tensile and impact properties changes of HASTELLOY X after exposure in high-temperature helium environment

Experimental results are presented on the changes in mechanical properties of HASTELLOY X* after being used in the liner tube of HENDEL hot gas duct under high temperature helium gas for about 6000 hours. In both room and elevated-temperature tensile tests, 0.2 pct proof stress and total elongation were significantly decreased after exposure in high temperature helium. Room-temperature impact toughness of the exposed specimens exhibited a much lower absorbed energy (about 5.0 × 106 J/m2) than that of unexposed specimens (about 1.5 × 106 J/m2). The fracture modes of tensile test specimens were more closely correlated with the test temperature than with the long-time exposure; however, long-time exposure is more affected by the tensile strength of HASTELLOY X than the test temperature. Moreover, “downstream effect” for the carbide precipitation reaction occurred in the liner tube of the HENDEL hot gas duct.

Low contractile and laminated chromium gun tube coatings from a pumped-flow plating system

SummaryTwo gun tube liners, one plated with low contractile chromium and the other laminated with alternate layers of high and low contractile coating produced in a pumped flow rig, are examined after firing tests. Crack propagation in the substrate is clearly related to the thickness of the heat affected zone, and there are some indications that lamination interfaces may inhibit crack propagation in the coating and coating recrystallisation.

Chromium as a gun tube liner

Chromium as a gun tube liner