Pipe Structure Research Articles

Simulation research on the protection performance of fall protection net at the end of truck escape ramp.

Although the fall protection net installed at the end of the truck escape ramp has a protective effect on trucks and drivers, but lacks sufficient theoretical basis and verification method. The primary objective of this paper was to design a fall protection net that meets the regulations and research its protection performance. The finite-element method was used to design the overall size, material, mesh length, mesh type, shape, and supporting structure of the fall protection net installed at the end of truck escape ramp, then dummy and truck models were used to impact the fall protection net to verify the rationality of the design. After the design completed, the truck model was used to impact the fall protection net twice to research the cumulative protection performance. A fall protection net with a width of 6000 mm, a span of 6000 mm, a depth of 5196 mm, a mesh length of 150 mm, a mesh type of diamond mesh, a shape of 60-degree V-shaped, a supporting structure of steel pipe supporting has a better effect on energy absorption and protection. Within the two consecutive impacts, the residual plastic deformation and stress of the fall protection net generated in the first impact severely affect the protection performance in the second impact. It is feasible to use the finite-element method to design and research the fall prevention net installed at the end of the truck escape ramp, and the fall protection net can indeed protect the trucks and drivers, and it should be inspected and maintained after impact to ensure the protective performance in subsequent use.

Analisis Konstruksi Pipa Pompa Suction 112-JB

The 101-JTC condenser tank has excess steam condensate due to the addition of admission steam from 101-JT. Therefore, it is necessary to design a piping system that connects 101-JTC condenser tank with the 112-JB pump to drain the condensed excess steam. The designed piping system will encounter a dynamic response caused by fluid flow fluctuation over the time. This dynamic response causes the pipe to experience stress. To find out the resulting voltage which will not cause damage or failure, it is necessary to estimate the safety factor in a piping system that has been given static and dynamic loading. This research uses the fluid structure interaction or FSI method with the help of ANSYS software as a simulation tool. The results of this study are, the flow in the pipe causes an impact load which makes the structure vibrate freely damped. The resulting dynamic response describes, the structure displacement amplitude decreases with increasing time. This indicates a stable vibration. Finally, when viewed from the value of stress against time, the fatigue that occurs in the pipe structure induce a stress below the stress limit on Goodman diagram. It can be estimated that the structure has no service life limit. The fatigue safety factor is 7.1.

Changes in soil temperature and water content under mobile soil steam disinfection

The soil steam injection method is one of the most effective disinfection methods, and the determination of the steam pipe structure parameters is very important. The steam capillary diameter (SCD) affects the steam flow field in each pipe, which in turn affects the steam changes in the soil flow range and soil temperature (ST). Larger SCD would make lower ST in clay loam, silt loam, and sandy clay loam. The effectiveness of an SCD of 10 mm was verified by a mobile disinfection test at walking speeds of 10 cm/min and 30 cm/min under soil water content (SWC) of 15% and 35%, respectively. The results showed that when the walking speed was 10 cm/min, the initial SWC was proportional to the ST. However, when the walking speed was 30 cm/min, the law was exactly the opposite; that is, the initial water content is inversely proportional to the ST. The research can provide a theoretical research foundation for increasing soil temperature for efficient soil steam disinfection. Keywords: soil steam disinfection, steam capillary diameter, steam capillary vent, soil temperature, soil water content DOI: 10.25165/j.ijabe.20211403.5026 Citation: Yang Z J, Wang X C, Ameen M. Changes in soil temperature and water content under mobile soil steam disinfection. Int J Agric & Biol Eng, 2021; 14(3): 140–147.

An experimental investigation on mechanical performances of 3D printed lightweight ABS pipes with different cellular wall thickness

In recent years, cellular structures have attracted great deal of attention of many researchers due to their unique properties like exhibiting high strength at low density and great energy absorption. Also, the applications of cellular structures (or lattice structures) such as wing airfoil, tire, fiber and implant, are mainly used in aerospace, automotive, textile and biomedical industries respectively. In this investigation, the idea of using cellular structures in pipes made of acrylonitrile butadiene styrene (ABS) material was focused on and four different pipe types were designed as honeycomb structure model, straight rib pattern model, hybrid version of the first two models and fully solid model. Subsequently, these models were 3D printed by using FDM method and these lightweight pipes were subjected to compression tests in order to obtain stress-strain curves of these structures. Mechanical properties of lightweight pipes like elasticity modulus, specific modulus, compressive strength, specific compressive strength, absorbed energy and specific absorbed energy were calculated and compared to each other. Moreover, deformation modes were recorded during all compression tests and reported as well. The results showed that pipe models including lattice wall thickness could be preferred for the applications which don’t require too high compressive strength and their specific energy absorption values were notably capable to compete with fully solid pipe structures. In particular, rib shape lattice structure had the highest elongation while the fully solid one possessed worst ductility. Lastly, it is pointed out that 3D printing method provides a great opportunity to have a foresight about production of uncommon parts by prototyping.

Characterization and modelling of the mechanical behaviour of metal rings: Application to a brass bullet jacket

Tubular or pipe structures are commonly found in various engineering applications, such as offshore pipelines, parts in the nuclear and automotive industries. Standard mechanical testing methods like compression tests on cylindrical samples or tensile tests on dog-bone samples are often out of questions due to the geometry restraints. Carrying out standardized mechanical characterization on ring-shaped samples could thus be a solution. The goal of this paper is to successfully conduct mechanical characterization of copper alloy rings, which are extracted directly from the jackets of small calibre ammunition. Firstly, an experimental protocol has been established to investigate their mechanical behaviour in the quasi-static regime. The strain rate and temperature sensitivities have also been evaluated through the same experimental process. Furthermore, a Johnson-Cook constitutive material model has been identified using an inverse analysis of lateral compressive experiments. This identification is based upon the ABAQUS/Standard ® finite element software coupled with the optimization software LS-OPT®.As a result, a low anisotropic material behaviour is demonstrated. Finite element simulations using identified parameters are in accordance with the experimental measurements from compressive tests in axial direction.

Control of a Switched Mode Fuel Thermal Management System

A novel flexible fuel thermal management architecture with a switched mode control strategy is proposed that provides a framework for increasing the thermal endurance of aircraft that use fuel as a heat sink. Multiple flow topologies within this architecture can be realized by using two valves to provide a range of fuel recycling configurations. The flexible thermal management system uses multiple modes of operation to achieve the goal of extending thermal endurance by switching between modes to achieve the best available configuration given the current operating condition. Dynamic inversion-based controllers are developed for each mode and are used to regulate the temperature at the hottest point in the system to a desired value. A high-level supervisory controller switches among four separate feedback control laws and manages the available flow paths within a fixed structure of pipes, valves, and tanks. The flexible fuel thermal management architecture and controller are tested over a range of simulated operating conditions. Under these conditions, the supervisory controller chooses a path that stores returning hot fuel to avoid overheating of aircraft systems and releases the hot fuel when excessive heat loads are no longer present. The proposed architecture allows for a large operational envelope.

A Method to Design and Optimize Axial Flow Cyclones for Gas–Liquid Separation

Abstract This article provides a detailed design guide, optimization, and performance assessment for air–water separation of an axial flow cyclone. Axial flow cyclones (also known as swirl tube demisters, mist eliminators, or Austin–Write cyclones) have a range of applications in several different industries. This method of gas–liquid separation offers many benefits. Among these are high liquid separation efficiencies (near 99%) and an inline design that allows them to be more easily fitted into existing piping structures. Despite these benefits, there are several design parameters that have not been optimized for performance in wastewater purification applications. This research fills the gap in the literature by quantifying the effect of new design parameters on water collection efficiency, ηwater collection, and the air bypass efficiency, ηair bypass, defined as the ratio of the air mass flowrate exiting through the desired air outlet over the inlet air mass flowrate. A set of wide-ranging experiments were conducted to study the effects of gas–liquid flow rates, tube geometry, and relative injection angles to optimize the water collection and air bypass efficiencies. The water collection efficiency exceeded 99.8% when the liquid streamline came in direct contact with the water drainage exit. An empirical correlation was developed to predict the swirl pitch as a function of the above design parameters. Predictions from the correlation were within 10% of the experimental results. The correlation can be used to design highly efficient in-line gas–liquid separators.

Experimental Diagnosis of the Heat Pipe Solar Collector Malfunction. A Case Study

Work was carried out to diagnose irregularities in the operation of a vacuum-tube solar collector. Experimental investigations of the collector were carried out at the solar collector field test stand in the Laboratory of Solar Collectors at the Koszalin University of Technology. The scope of the work included the following: research on thermal efficiency characteristics, research on the temperature distribution on the solar collector manifold, and research on the geometric structure of the heat pipe and filling with the working medium. Based on the diagnostic tests carried out, the occurrence of incorrect sedimentation in the condenser on the neck of the heat pipe (44%) and an incorrect amount of working medium (66%) were found. The results show that the functioning of the heat pipe significantly depends on its geometric structure and the amount of working medium. Any irregularity at the production stage contributes to a reduction in the thermal efficiency of the solar collector. The results of the experimental research presented in this paper can be used in the diagnostic analyses of solar systems as well as in the organisation of the manufacturing processes of these systems.

Focused methane migration formed pipe structures in permeable sandstones: Insights from uncrewed aerial vehicle‐based digital outcrop analysis in Varna, Bulgaria

AbstractFocused fluid flow shapes the evolution of marine sedimentary basins by transferring fluids and pressure across geological formations. Vertical fluid conduits may form where localized overpressure breaches a cap rock (permeability barrier) and thereby transports overpressured fluids towards shallower reservoirs or the surface. Field outcrops of an Eocene fluid flow system at Pobiti Kamani and Beloslav Quarry (ca 15 km west of Varna, Bulgaria) reveal large carbonate‐cemented conduits, which formed in highly permeable, unconsolidated, marine sands of the northern Tethys Margin. An uncrewed aerial vehicle with an RGB sensor camera produces ortho‐rectified image mosaics, digital elevation models and point clouds of the two kilometre‐scale outcrop areas. Based on these data, geological field observations and petrological analysis of rock/core samples, fractures and vertical fluid conduits were mapped and analyzed with centimetre accuracy. The results show that both outcrops comprise several hundred carbonate‐cemented fluid conduits (pipes), oriented perpendicular to bedding, and at least seven bedding‐parallel calcite cemented interbeds which differ from the hosting sand formation only by their increased amount of cementation. The observations show that carbonate precipitation likely initiated around areas of focused fluid flow, where methane entered the formation from the underlying fractured subsurface. These first carbonates formed the outer walls of the pipes and continued to grow inward, leading to self‐sustaining and self‐reinforcing focused fluid flow. The results, supported by literature‐based carbon and oxygen isotope analyses of the carbonates, indicate that ambient seawater and advected fresh/brackish water were involved in the carbonate precipitation by microbial methane oxidation. Similar structures may also form in modern settings where focused fluid flow advects fluids into overlying sand‐dominated formations, which has wide implications for the understanding of how focusing of fluids works in sedimentary basins with broad consequences for the migration of water, oil and gas.

Research on the plume stability of air bubble curtains under low transverse flow velocity environment in dredging engineering

Air bubble curtain anti-fouling systems, which meet both the environmental standards of suspended solids diffusion and navigation requirements, have unique advantages in environmental dredging technology. Through the bubble plume formed by dense bubble hole jets, the bubble curtain blocks the material exchange between the designated area and other areas in the water to prevent the diffusion of suspended pollutants and protect the water environment. The protection efficiency of the bubble curtain is determined by the fusion of the bubble flow in the rising process and the stability of the plume under the action of a cross flow. The feasibility of a bubble curtain in field engineering is evaluated in this paper. Using two fluid models, the time-varying process of bubble fusion and migration in a bubble plume is analyzed. The dynamic behavior characteristics of the bubble plume are obtained, and the factors influencing the stability of the bubble plume are quantitatively described. The results show that the turbidity of the water body decreases in front of and behind the bubble curtain, which proves that the bubble curtain system is practical in dredging engineering. The number, size range and median value of bubbles in the flume are related to the ventilation pressure and pipe structure. There are three different phenomena in the half-width of the bubble plume at different heights. With the general linear model, it is concluded that the fusion height of the bubble plume is the most sensitive to the change in the bubble tube hole spacing and that the migration characteristics of the bubble plume are most significantly affected by the air flow at the bubble hole. The mechanical analysis of the plume stability shows that the Weber number is the most important parameter affecting the failure of the bubble curtain.

General analytical solution for vibrations of pipes with arbitrary discontinuities and generalized boundary condition on Pasternak foundation

Discontinuities of the shear force, bending moment, slope, and deflection can be caused by span supports, valves, and cracks etc. For arbitrary discontinuities appearing in the oil-conveying pipe resting on Pasternak foundation, the general analytical solution for vibrations of this structure is presented in this paper. To deal with discontinuity terms, generalized functions are employed to express the model displacement of the entire pipe as a single function. This function is then solved by Laplace transform. Continuity conditions at discontinuity points are also given. In addition, the generalized boundary condition (BC), which can be degenerated to many classical BCs, is considered. Numerical section testifies the feasibility and the validity of present solutions, and discusses the effects of some physical parameters on natural frequencies. It is shown that the closer the cracks are to the nearest nodes of mode shapes, the less effects they have on the corresponding natural frequencies; locations of support springs change effects of cracks on natural frequencies by affecting positions of structural nodes; foundation parameters have different effects on natural frequencies. The present method can be applied in maintaining safety and integrity of structures of pipes.

Unified Approach to the Motion Design for a Snake Robot Negotiating Complicated Pipe Structures.

A unified method for designing the motion of a snake robot negotiating complicated pipe structures is presented. Such robots moving inside pipes must deal with various “obstacles,” such as junctions, bends, diameter changes, shears, and blockages. To surmount these obstacles, we propose a method that enables the robot to adapt to multiple pipe structures in a unified way. This method also applies to motion that is necessary to pass between the inside and the outside of a pipe. We designed the target form of the snake robot using two helices connected by an arbitrary shape. This method can be applied to various obstacles by designing a part of the target form specifically for given obstacles. The robot negotiates obstacles under shift control by employing a rolling motion. Considering the slip between the robot and the pipe, the model expands the method to cover cases where two helices have different properties. We demonstrated the effectiveness of the proposed method in various experiments.

Effect of Preliminary Deformation of Continuously Cast Billets by Radial-Shear Rolling on the Structure and Properties of Hot-Rolled Chromium-Containing Steel Pipes

The paper analyzes the effect of preliminary deformation of continuously cast billets (CCB) made of chromium-containing grades of steel by radial-shear rolling (RDR) on the structure and properties of seamless pipes. A bar stock measuring 105 mm in diameter was obtained using an RDR mill at large feed angles (β = 21°). A comparative analysis of the microstructure of the initial CCB and hotrolled bars has shown that radial-shear rolling enables intensive refinement of the structure of continuously cast billets, and ensures a high-quality (70 to 90%) work-up of the cast structure at reduction ratios of 2.0 to 2.2. A pipe-rolling mill (PRM) installed at the Pervoural’sk New Pipe Plant JSC (PNPP JSC) was used to obtain seamless pipes from the deformed bars, and the mechanical properties of such pipes were studied. It was found that the pipes obtained from the experimental billets are fully compliant with the ISO 11960:2004 requirements for strength group J55 (σt > 517 MPa; σ0.2 > 379 MPa; δ > 16%). In addition, the level of plastic properties of the experimental pipes (based on present elongation δ5, %) exceeds the ISO 11960:2004 requirements by 1.6–1.8 times. To achieve a comparable level of properties using the existing technology, an additional heat treatment (HT) is required, which points to the potential advantages of using RDR pre-deformed billets to obtain seamless pipes with the required properties.

Finite Element Simulation of Distressed Prestressed Concrete Cylinder Pipes Embedded in Soils

Durability problems often occur to the prestressed concrete cylinder pipe embedded in aggressive soil environment. The residual performance assessment of damaged pipes is the basis of the maintenance strategy. This study proposes a soil-pipe interaction framework to simulate the limit states of the pipe with path-dependent modelling of each part of the pipe structure, surrounding soil and the contact state between them. Based on the analytical results, the limit states of the pipe can be ranked. Further sensitive analyses showed significance of the nonlinear soil-pipe interactions and the exact deformation is recognized as the aim of the future study.

Carbonized porous wood as an effective scaffold for loading flower-like CoS, NiS nanofibers with Co, Ni nanoparticles served as electrode material for high-performance supercapacitors

A novel hybrid composed of carbonization lignin-free wood as an effective scaffold for loading CoS, NiS nanofibers with Co, Ni flower-like structure attached Co, Ni nanoparticles is fabricated as electrode material for high-performance supercapacitor. For the resultant, the natural porous pipe structure of wood provides a large number of electrolyte ions channels for the hybrid. The flower-like NiS, CoS distributed along the carbonized wood pipe gather together to form NiS nanofibers. These NiS and CoS nanofibers interweave with each other to form some new pores, which is helpful for the transport of electrolyte ions. As a result, the synergistic effect of these components endows the wood-based hybrid with good supercapacitive performance: high gravity (volumetric) energy densities of 46 Wh kg−1 (66 Wh L-1) are obtained, meanwhile sustaining high gravity (volumetric) power densities of 68 kW kg−1 (50 kW L-1).

Study of refrigerant mal-distribution and optimization in distributor for air conditioner

The distribution of two-phase refrigerant has a crucial influence on the efficiency of heat exchanger. Only when the two-phase refrigerant is evenly distributed to each path can the heat exchanger be utilized efficiently. The study aims at exploring the causes of the mal-distribution of refrigerant and designing an optimized structure to mitigate the phase separation and improve the refrigerant distribution. Moreover, the rules of each factor on the distribution are studied. In this paper, Taguchi method is proposed to obtain the importance of each factor on the distribution. The results show that the distance between the elbow and entrance of the distributor, the turning angle and turning radius of the elbow have significant effects on distribution. Finally, the optimized structure of the inlet pipes is proposed. Compared with the traditional structure, the optimized structure has a significant effect on improving the phase separation and the pressure drop is relatively stable. Besides, the optimized structure has low cost and simple production and processing, which provides a new idea for improving refrigerant distribution.

Numerical analysis of the effect of solid rod on the flow field and separation performance of thick-walled overflow pipe hydrocyclone

Hydrocyclone is one of the common equipment for solid-liquid separation. Although the hydrocyclone has a simple structure, it has many shortcomings. Among them, short-circuit flow and air core are two important factors that affect the separation performance. Many researchers have tried to weaken the short-circuit flow by changing the structure of the overflow pipe and the trajectory of the particles. This is certainly a feasible method to reduce the short-circuit flow. Is it possible to reduce the short-circuit flow by increasing the movement distance of the short-circuit flow and re-entering the short-circuit flow into the separation area without changing the structure of the overflow pipe? The answer is yes. In this paper, a thick-walled overflow pipe structure was proposed to increase the distance of the short-circuit flow into the bottom end of the overflow pipe.In the proposed structure, the particles in the short-circuit flow can be brought back into the separation area through the circulating flow at the bottom of the overflow pipe. During the working process, the hydrocyclone produces a unique phenomenon-air core. Although the air core does not participate in particle separation, it consumes energy and compresses the separation area. In order to further improve the separation performance of the thick-walled overflow pipe hydrocyclone, a central solid rod was traversed throughout the hydrocyclone to weaken the air core. In addition, FLUENT was used to numerically analyze the thick-walled overflow pipe hydrocyclone with an inserted solid rod in the center. Moreover, we investigated the effect of the solid rod with different diameters on the separation performance of the hydrocyclone. The numerical simulation was verified by comparing the simulation data with the classic data. The results showed that the pressure distribution of the thick-walled overflow pipe hydrocyclonewas more reasonable. The inserted solid rod significantly improved, the pressure distribution. Compared with the conventional hydrocyclone, the short-circuit flow rate of the thick-walled overflow pipe hydrocyclone was reduced by 8.09%. The cutting size of the particles can be adjusted by changing the diameter of the solid rod. When the diameter of the solid rod was 5–6 mm, the cutting size was in the range of 11.6–12.2 μm. When the diameter of the solid rod exceeded 6 mm, the cutting size gradually increased. The appropriate diameter of the solid rod can improve the separation accuracy of thick-walled overflow pipe hydrocyclone, resulting in thinner and higher quality products.

Cavitation effect in two-dimensional ultrasonic rolling process

The ultrasonic cavitation effect can improve the machining quality. In order to study the formation process of cavitation in two-dimensional ultrasonic rolling process (TDUR) and its influence on processing, a simulation and experimental study of cavitation in TDUR was conducted to further improve the processing quality. The pressure distribution model and the cavitation model of the two-phase mixed flow around the roller in TDUR were constructed by combining the ideal bubble dynamics theory. And the cavitation intensity was evaluated by the vapor volume fraction (VVF). The formation process of cavitation effect in the flow field was analyzed by finite element analysis, and the effects of different inlet pressures and different pipe structures on the cavitation were studied. TDUR experiments were carried out to study the changes of surface roughness and residual stress of the workpiece under the effect of ultrasonic cavitation, and the positive effect of cavitation effect was verified. The simulation results show that the cavitation effect mainly occurs in the left half of the roller and the rolling area, and the cavitation in the left half of the roller changes from transient cavitation to steady-state cavitation as the inlet pressure increases. Different inlet pressures in the rolling region always show periodic transient cavitation, with obvious cavitation bubbles generation, expansion and collapse processes. The lower the inlet pressures in the straight and inverted trumpet pipe, the stronger the transient cavitation effect. The experimental results show that the cavitation effect can further improve the surface strengthening quality of the workpiece. Under the same process parameters, the surface roughness of the workpiece can be reduced by up to 47.7% and the residual compressive stress of the surface can be increased by up to 10.2%. Therefore, the cavitation effect can be applied in ultrasonic rolling process to further improve the surface strengthening quality, and the straight pipe at atmospheric inlet pressure is preferred in TDUR.

Fuzzy-Based Multi-Objective Design Optimization of Buried Pipelines

This paper proposes fuzzy-based multi-objective design optimization approach for the optimal analysis of buried pipe based on the expected value of a fuzzy output variable when the membership function is computed. The design of pipe structures is usually associated with uncertainties. Therefore, the principle of fuzzy set and a multi-objective optimization algorithm is applied to account for the variabilities associated with the uncertain parameters to ensure an acceptable performance against the impact of uncertainties. Different methods such as deterministic and non-deterministic methods have been proposed to model the effect of uncertainties and analyse the performance of engineering structure in the literature. Herein, a fuzzy-based uncertainty modelling approach that employs the optimal performance of a hybrid GA-GAM for the analysis of a buried pipeline is proposed. The purpose of the strategy is to optimise the design variable while considering the adverse effect of the uncertain fuzzy variables and variability of the structural performance. The uncertain fuzzy variable is used in the analysis to take into account the subjective nature of the corrosion process, while the entropy of a fuzzy variable used as a global measure of variable dispersion is employed to measure the variability and sensitivity of the structural response. The outcome of the fuzzy-based multi-objective design optimization provides a set of optimal solution for the analysis of fuzzy structure. Finally, the applicability and characteristic of this method are demonstrated using a numerical example, and the outcome denotes acceptable analytical tools for design engineers and can be applied to analyse other engineering structures.

Biomimetic design of fibrous composite structures

The paper is devoted to the analysis of the use of Nature’s methods in the design of composite structures, in particular, with the use of optimal curvilinear paths for laying fibers. In the first part models of different structural levels in macro-, mini-, micro-mechanics of composites are noted. The second part includes analysis of the optimal elastic-strength properties of wood and composites for crack stopping by weak interfaces. The third part is devoted to methods for modeling curvilinear fibers trajectories “flowing around the holes”. In the fourth part the technologies for manufacturing joints are analyzed in which holes are formed using curved fiber trajectories. The fifth part describes the “bio-inspired” principles for the optimal design of composite pipe structures which are similar to multilink bamboo stems. In the sixth part examples of the effective use of fiber composites in elastic elements are considered. The seventh part is devoted to the intensively developing additive technologies of three-dimensional printing of parts made from fiber composites with laying the fibers along the calculated trajectories. The role of composite technologies in creating structures in open space is analyzed.