Cylindrical Liner Research Articles

Compression behavior of large-scaled cylindrical GFRP chimney liner segments

As a pivotal anti-corrosion structure in the wet flue gas desulfurization system, the huge filament-wound GFRP (glass fiber-reinforced polymer) tube is often employed as the chimney liner. However, the study on its mechanical properties is rare. Three large-scale stiffened cylindrical GFRP chimney liner segments were tested under the axial compression, including an integrated filament-wound chimney liner specimen with two ring stiffeners, a specimen with two ring stiffeners cut into two segments and joined by a hand-wound technique, and a specimen with an outside ring bracket. The failure modes, load-displacement relationships, variation of strains during the loading process, were acquired by test. The effects of ring stiffeners on the mechanical behavior, service reliability of the joint between the two segments of the chimney liner, and the reliability of the ring bracket were examined. Comparisons between theoretically calculated stiffness and experimentally measured stiffness were discussed. Finally, finite element analysis was performed to examine the failure modes and axial load-displacement behavior of the investigated chimney liners. Different ranges of diameter to thickness ratios and load eccentricity values were selected to examine their effects on the mechanical behavior of chimney liners. Finally, suggestions on the design of chimney liner structure were given.

Magneto-Rayleigh–Taylor Instability Driven by a Rotating Magnetic Field: Cylindrical Liner Configuration

We propose using a directional time-varying (rotating) driving magnetic field to suppress magneto-Rayleigh-Taylor (MRT) instability in dynamic Z-pinches. A rotational drive magnetic field is equivalent to two magnetic-field components, {\Theta} and Z, that alternate in time, referred to as an alternate Theta-Z-pinch configuration. We consider the finitely thick cylindrical liner configuration in this paper. We numerically integrate the perturbation equation to stagnation time based on the optimal background unperturbed trajectories. We assess the cumulative growth of the dominant mode selected by some mechanism at the beginning of an implosion. The maximum e-folding number at stagnation of the dominant mode of an optimized alternate Theta-Z-pinch is significantly lower than that of the standard Theta- or Z-pinch. The directional rotation of the magnetic field contributes to suppress the instabilities, independent of the finite thickness. The finite thickness effect plays a role only when the orientation of the magnetic field varies in time whereas it does not appear in the standard Theta- or Z-pinch. The rotating frequency of the magnetic field and the thickness of liner are both having a monotonic effect on suppression. Their synergistic effect can enhance the suppression on MRT instability. Because the MRT instability can be well suppressed in this way, the alternate Theta-Z-pinch configuration has potential applications in liner inertial fusion. This work is supported by the NSFC (Grant Nos. 11405167, 51407171, 11571293, 11605188, and 11605189) and the Foundation of the China Academy of Engineering Physics (No. 2015B0201023).

Mechanical behavior of cylindrical GFRP chimney liners subjected to axial tension

The large diameter filament-wound glass fiber reinforced polymer (GFRP) tube as the chimney liner is a pivotal anti-corrosion structure in the wet flue gas desulfurization system. Fourteen GFRP specimens with a larger size (3000 mm × 1100 mm × 5.6 mm) and twenty GFRP specimens with a smaller size (350 mm × 25 mm × 5.6 mm) have been investigated by tensile tests. All specimens were cut from two GFRP chimney liner specimens, which were fabricated with the scaled-down ratio of 3:1 (practical to experimental) according to the standard guide for design of GFRP chimney liners for coal-fired units. Among the fourteen larger specimens, seven specimens were cut into two segments and then jointed by the hand-wound technique at the middle height of the specimens, while the other seven larger specimens and twenty smaller specimens were integrated. All specimens were subjected to axial tension at four different temperatures, including the ambient temperature (approximately 30 °C), 60 °C, 90 °C, and 120 °C. Based on the tests, the failure modes and tensile load-displacement relationships were determined. The temperature-dependency and size-dependency of the tensile strength, tensile strain, and elastic modulus were analyzed. Moreover, the comparisons between integrated and jointed specimens were examined. Finally, a modeling method for the tensile mechanical properties of composites under elevated temperatures was proposed for GFRP chimney liner design.

Acoustic damping: Analytical prediction with experimental validation of mixed porosity liners and analytical investigation of conical liners

Acoustic liners are widely used as passive damping devices to suppress acoustically driven combustion instabilities in jet engines. In this paper, analytical models for conical cavity-liner duct and liners with mixed porosity are developed by a control volume approach that account for acoustic coupling with the present mean flows. The developed analytical model has been generalised to any combination of liner and cavity section. Furthermore, the damping performance of liners of uniform and mixed porosity is investigated experimentally. In order to investigate the liner damping behavior experimentally, the two load method with convective wave numbers has been used. The performance of the mixed porosity cylindrical and conical liners is compared with that of a uniform porosity cylindrical liner. The troughs of absorption curves are observed to get shifted with the changing cone angles. The effects of changing cavity cone angles for the fixed liner cone angle and vice versa on the absorption have been also analyzed.

The output of a shock wave on the inner surface of a cylindrical liner

The results of the experimental investigations of the dynamics of the axisymmetric compression of a metallic liner are presented in this work. The studies were carried out using a high-speed camera with nanosecond resolution. It is shown that the detonation wave formed by the multipoint initiation method has a complex three-dimensional cellular structure, where first-order node lines and second-order nodes are present. The hydrodynamic instabilities formed upon the exit of the shock wave onto the inner surface of a metallic liner do not smooth out as they contract, but increase.

Microparticles and plasma stream registration during cylinder compression of a metal liner

In this paper, the authors show the possible way of registration of the microparticles and plasma jets escaping from the inner surface of metal cylindrical liner when the detonation wave reaches it. The liner is allocated within experimental setup and is compressed by detonation products. Jets have been registered by Langmuir gauge which connection circuit was developed by the authors. The authors also developed a technique a method for detecting the signal under study. Average particle (about 4 km/s) and plasma (about 7 km/s) jet velocity is estimated by using the developed technique for copper liner compressed by detonation products. The results of this experiment correlate with those for plane setup.

Thermal Stress Analysis of Residual Stress in a Cylindrical Aluminum Casting with Cast-in GCI Liner, Taking Recovery Behavior Effect into Account

Most aluminum cylinder blocks produced using high-pressure or low-pressure die-casting processes require gray cast iron liners (GCI liners) to compensate for their insufficient wear resistance and heat resistance of the Al-Si-Cu alloys. However, the cast-in liners cause excessive residual stress at the cylinder bore region. The resultant residual stress induces distortion of the cylinder liner. These inconveniences hinder development of more efficient engines. Therefore, an accurate thermal stress analysis technique has been sought to predict the residual stress and distortion of the cylinder liner. For accurate thermal stress analysis, we have already developed an elastoplastic-creep constitutive equation for which the inelastic strain developed at high temperatures does not contribute to strain hardening that occurs at low temperatures by duplicating the recovery behavior. Our earlier investigation using this equation has already revealed that incorporation of the recovery in the alloy constitutive equation is effective for improving the prediction accuracy of the thermal stress developed during casting. However, this conclusion was obtained only for a simple shape casting with a uniaxial thermal stress state. Effects of the developed constitutive equation have not been discussed for a casting closer to an actual cylinder block. For this study, a cylindrical aluminum casting with GCI (ISO 300) insert was produced. Then, the circumferential strain of the GCI liner was measured in-situ during casting. Measurements were taken of the residual stresses of the cylindrical aluminum casting and GCI liner, and of the liner deformation at a room temperature. The experimentally obtained results supported a discussion of the predictive accuracies of the elastoplastic-creep constitutive equation and the classical elastoplastic constitutive equation. A comparison revealed that the elastoplastic-creep constitutive equation for the aluminum casting has better predictive accuracy than the classical elastoplastic equation for residual stress, liner deformation, and the circumferential strain of a GCI liner during casting. Investigation of the simulated strain components of the cylindrical aluminum casting during casting indicated incorporation of the recovery in the alloy constitutive equation as a main factor improving the predictive accuracy.

Evolution of sausage and helical modes in magnetized thin-foil cylindrical liners driven by a Z-pinch

In this paper, we present experimental results on axially magnetized (Bz = 0.5 – 2.0 T), thin-foil (400 nm-thick) cylindrical liner-plasmas driven with ∼600 kA by the Michigan Accelerator for Inductive Z-Pinch Experiments, which is a linear transformer driver at the University of Michigan. We show that: (1) the applied axial magnetic field, irrespective of its direction (e.g., parallel or anti-parallel to the flow of current), reduces the instability amplitude for pure magnetohydrodynamic (MHD) modes [defined as modes devoid of the acceleration-driven magneto-Rayleigh-Taylor (MRT) instability]; (2) axially magnetized, imploding liners (where MHD modes couple to MRT) generate m = 1 or m = 2 helical modes that persist from the implosion to the subsequent explosion stage; (3) the merging of instability structures is a mechanism that enables the appearance of an exponential instability growth rate for a longer than expected time-period; and (4) an inverse cascade in both the axial and azimuthal wavenumbers, k and m, may be responsible for the final m = 2 helical structure observed in our experiments. These experiments are particularly relevant to the magnetized liner inertial fusion program pursued at Sandia National Laboratories, where helical instabilities have been observed.

The electro-thermal stability of tantalum relative to aluminum and titanium in cylindrical liner ablation experiments at 550 kA

Presented are the results from the liner ablation experiments conducted at 550 kA on the Michigan Accelerator for Inductive Z-Pinch Experiments. These experiments were performed to evaluate a hypothesis that the electrothermal instability (ETI) is responsible for the seeding of magnetohydrodynamic instabilities and that the cumulative growth of ETI is primarily dependent on the material-specific ratio of critical temperature to melting temperature. This ratio is lower in refractory metals (e.g., tantalum) than in non-refractory metals (e.g., aluminum or titanium). The experimental observations presented herein reveal that the plasma-vacuum interface is remarkably stable in tantalum liner ablations. This stability is particularly evident when contrasted with the observations from aluminum and titanium experiments. These results are important to various programs in pulsed-power-driven plasma physics that depend on liner implosion stability. Examples include the magnetized liner inertial fusion (MagLIF) program and the cylindrical dynamic material properties program at Sandia National Laboratories, where liner experiments are conducted on the 27-MA Z facility.

Сравнение различных математических и численных моделей движения цилиндрического лайнера и их проверка

Сравнение различных математических и численных моделей движения цилиндрического лайнера и их проверка

Elastic buckling of thin-walled polyhedral pipe liners encased in a circular pipe under uniform external pressure

In this study, a thin-walled polyhedral polymer pipe liner is proposed for the internal rehabilitation of a deteriorated/cracked underground circular metal pipe. The pipe liner is externally confined and subjected to the hydrostatic pressure of water seeped through the cracked pipe. The critical buckling pressure of the pipe liner is derived analytically based on the principle of minimum potential energy and compared with that of a cylindrical pipe liner. A finite element model of the pipe liner is established and analyzed to understand pressure-deformation equilibrium paths and the stability of post-buckling behavior. The analytical buckling pressure is in excellent agreement with the numerical results. The buckling pressure of a polyhedral liner increases with the increase of thickness-to-radius ratio and the decrease of the number of sides in polygon base shape. In comparison with the cylindrical liner, the polyhedral liner can increase buckling pressure up to 10 times but result in a less stable post-buckling behavior.

Technique for insulated and non-insulated metal liner X-pinch radiography on a 1 MA pulsed power machine

Broadband, high resolution X-pinch radiography has been demonstrated as a method to view the instability induced small scale structure that develops in near solid density regions of both insulated and non-insulated cylindrical metallic liners. In experiments carried out on a 1-1.2 MA 100-200 ns rise time pulsed power generator, μm scale features were imaged in initially 16 μm thick Al foil cylindrical liners. Better resolution and contrast were obtained using an X-ray sensitive film than with image plate detectors because of the properties of the X-pinch X-ray source. We also discuss configuration variations that were made to the simple cylindrical liner geometry that appeared to maintain validity of the small-scale structure measurements while improving measurement quality.

Selection of Structural Dimensions of Twin Liners of a Mud Pump Cylinder and Calculation of Strength of Coupling with Assured Tightness

The possibility of extending the service life of the cylindrical liners of U8-6MA mud pumps is considered. It is suggested that cylindrical liners that have, to some extent, become worn out should be bored out and twin liners fabricated. The diametrical dimensions of the twin liners are given and the resulting forces that arise in the course of the shaft’s travel are calculated. Alternative rebore options under which the condition Tf < Psh holds are given.

Simulations of the Interaction of High-Velocity Condensed-Matter Liners With Walls

This paper presents an overview of publications on numerical simulations of one of the major 2-D effects observed in magnetically driven implosion of cylindrical condensed-matter liners: their interaction with glide planes. We consider liners accelerated to 8-20 km/s by currents of 30-100 MA delivered by disk explosive magnetic flux compression generators with azimuthal magnetic fields of 1-6 MG (magnetic pressures of 0.04-1.4 Mbar): experimental liners HEL-1, ALT-1, 2, and liners HEL-2, ALT-3 proposed for high energy density physics research.

Mass ablation and magnetic flux losses through a magnetized plasma-liner wall interface

The understanding of energy and magnetic flux losses in a magnetized plasma medium confined by a cold wall is of great interest in the success of magnetized liner inertial fusion (MagLIF). In a MagLIF scheme, the fuel is magnetized and subsonically compressed by a cylindrical liner. Magnetic flux conservation is degraded by the presence of gradient-driven transport processes such as thermoelectric effects (Nernst) and magnetic field diffusion. In previous publications [Velikovich et al., Phys. Plasmas 22, 042702 (2015)], the evolution of a hot magnetized plasma in contact with a cold solid wall (liner) was studied using the classical collisional Braginskii's plasma transport equations in one dimension. The Nernst term degraded the magnetic flux conservation, while both thermal energy and magnetic flux losses were reduced with the electron Hall parameter ωeτe with a power-law asymptotic scaling (ωeτe)−1/2. In the analysis made in the present paper, we consider a similar situation, but with the liner being treated differently. Instead of a cold solid wall acting as a heat sink, we model the liner as a cold dense plasma with low thermal conduction (that could represent the cryogenic fuel layer added on the inner surface of the liner in a high-gain MagLIF configuration). Mass ablation comes into play, which adds notably differences to the previous analysis. The direction of the plasma motion is inverted, but the Nernst term still convects the magnetic field towards the liner. Magnetization suppresses the Nernst velocity and improves the magnetic flux conservation. Thermal energy in the hot plasma is lost in heating the ablated material. When the electron Hall parameter is large, mass ablation scales as (ωeτe)−3/10, while both the energy and magnetic flux losses are reduced with a power-law asymptotic scaling (ωeτe)−7/10.

Sharpening of the front of the current through a cylindrical foil liner

Results are presented from experiments on the electromagnetic implosion of aluminum foil liners at the MIG generator with a current rise time of ≈80 ns. Plasma with a density of 1017 cm–3 was preliminarily injected into the liner region by using a set of radial plasma guns. The Lorentz force J × B causes plasma acceleration in the radial direction. Since the magnetic field pressure is inversely proportional to the radius squared, the plasma displacement is maximum near the liner surface. As a result, plasma motion becomes two-dimensional, a gap appears between the plasma and the liner, and the generator current is switched over to the liner. The plasma velocity at the liner surface is close to the local Alfven velocity, while the time during which the current is switched over to the liner is nearly equal to the ratio of the liner length to the Alfven velocity. The proposed scheme allows one to decrease the rise time of the current through the liner to several nano-seconds and, as a result, to reduce the initial liner radius and improve the stability of liner implosion.

Study the Effect of Rotational Speed and Pouring Temperature on the Wear Resistance and Hardness of Alloy (A380) Reinforced with Different Volume Fraction of Alumina Particles

In this study a cylindrical liner was produced by horizontal centrifugal casting process. The liner was composed from aluminum alloy (A380) matrix reinforced with alumina particles (Al2O3) with grain size of (63−125)μ and volume percent of 10,15 and 20%. The die was rotated at different speeds and its temperature was remained constant at (350)ºC.In this present study it was concluded that any increase in temperature difference between pouring and die temperature will reduce the surface defects. This study reveals that increasing the rotational speed refines the grain size but cause the alumina particles to be concentrated at the outer surface. Finally it was found that the addition of alumina particles increases both hardness and wear resistance of the alloy.

Modeling for compression of field-reversed configurations by an imploding liner

This article proposes a one-dimensional physical model to investigate the compression of reversed-field configurations (FRCs) by an imploding cylindrical liner. In this model, axial contraction of FRCs is included and parallel thermal conduction is considered as well as the radial, approximately in the open field line region of FRCs. Comparison with Spencer's analytic model of FRCs adiabatic compression shows similar results. Modeling results also indicate that classical transport model is preferred in the magnetized target fusion regime and axial contraction plays an important role in the dynamics of compression of FRCs using an imploding liner.

Helical plasma striations in liners in the presence of an external axial magnetic field

Awe et al. found on the 20 MA Z machine [Acta Phys. Pol. A 115, 956 (2009)] that applying an externally generated axial magnetic field to an imploding liner leads to a helical pattern in the liner when viewed with soft x-ray radiography ([Phys. Rev. Lett. 111, 235005 (2013)] and [Phys. Plasmas 21, 056303 (2014)]). Here, we show that this phenomenon is also observed in extreme ultraviolet self-emission images of 10 mm long cylindrical metal liners having varying diameters and varying wall thicknesses on a 1 MA, 100–200 ns pulsed power generator. The magnetic field in these experiments is created using either twisted return current wires positioned close to the liner, generating a time-varying Bz, or a Helmholtz coil, generating a steady-state Bz.

A new analytical model for vibration of a cylindrical shell and cardboard liner with focus on interfacial distributed damping

This paper proposes a new analytical model for a thin cylindrical shell that utilizes a homogeneous cardboard liner to increase modal damping. Such cardboard liners are frequently used as noise and vibration control devices for cylindrical shell-like structures in automotive drive shafts. However, most prior studies on such lined structures have only investigated the associated damping mechanisms in an empirical manner. Only finite element models and experimental methods have been previously used for characterization, whereas no analytical studies have addressed sliding friction interaction at the shell–liner interface. The proposed theory, as an extension of a prior experimental study, uses the Rayleigh–Ritz method and incorporates material structural damping along with frequency-dependent viscous and Coulomb interfacial damping formulations for the shell–liner interaction. Experimental validation of the proposed model, using a thin cylindrical shell with three different cardboard liner thicknesses, is provided to validate the new model, and to characterize the damping parameters. Finally, the model is used to investigate the effect of the liner and the damping parameters on the modal attenuation of the shell vibration, in particular for the higher-order coupled shell modes.