Pipe Expansion Research Articles

3D Finite Element Analysis on Mechanical Behavior of Completion Tubing String for Extra-Deep High Temperature Gas Well

3D Finite Element model was built for analysis of mechanical behavior of tubular system. Factors of wellbore trajectory deviation and frictional contact behavior between tube and casing are considered in the model. Loads of packer setting, hydraulic fracturing, and gas production are included. Numerical solutions of stress and displacement distribution along the tubing are presented. Principal results are: 1) Displacement distribution along the whole length of tubing. 2) Distribution of axial stress and von Mises stress along the whole length of tubing. 3) Distribution of displacement and stress along the tubing section below expansion pipe, as well as frictional contact stress and frictional force in this section.

Numerical analysis of swirling turbulent droplet-laden flow and heat transfer in a sudden pipe expansion

The effect of swirling intensity on the structure and heat transfer of a turbulent gas–droplet flow after a sudden pipe expansion has been numerically simulated. Air is used as the carrier phase, and water, ethanol, and acetone are used as the dispersed phase. The Eulerian approach is applied to simulate the dynamics and heat transfer in the dispersed phase. The gas phase is described by a system of Reynolds-averaged Navier-Stokes (RANS) equations, taking into account the effect of droplets on mean transport and turbulent characteristics in the carrier phase. Gas phase turbulence is predicted using the second-moment closure. A swirling droplet-laden flow is characterized by an increase in the number of small particles on the pipe axis due to their accumulation in the zone of flow recirculation and the action of the turbulent migration (turbophoresis) force. A rapid dispersion of fine droplets over the pipe cross-section is observed without swirling. With an increase in swirling intensity, a significant reduction in the length of the separation region occurs. The swirling of a two-phase flow with liquid droplets leads to an increase in the level of turbulence for all three types of liquid droplets investigated in this work due to their intensive evaporation. It is shown that the addition of droplets leads to a significant increase in heat transfer in comparison with a single-phase swirling flow. The greatest effect of flow swirling on heat transfer intensification in a two-phase gas-droplet flow is obtained for the droplets of ethanol and water and smallest effect is for the acetone droplets.

The Effect of separated Expansion Chamber Parameters on Exhaust Pressure Oscillations in Single Cylinder Motorcycle Engine

Abstract This paper investigates the effect of separated exhaust expansion chamber parameters on pressure oscillations in spark-ignited internal combustion (IC) gasoline engines. It is known that exhaust expansion chambers are becoming increasingly more popular among both – original equipment (OE) and aftermarket equipment (AE) exhaust system manufacturers for performance-oriented motorcycles equipped with mainly single cylinder engines, but the companies are reluctant to reveal any detailed principles of operation of the mentioned expansion chambers. The subject of this research is the type of expansion chamber (separate) as used on performance-oriented motorcycles, particularly its’ effect on exhaust pressure pulsations as different chamber volumes, locations and passage sizes are tested. Time-dependent computational fluid dynamics (CFD) analysis was carried out in Solidworks Flow Simulation environment on a simplified exhaust header pipe model imitating engine operation at full load and steady speed. Honda CRF450R motorcycle engine was used as the example and fully defined using a 1D engine performance calculator software to determine the combustion chamber pressure and exhaust valve lift at any given crankshaft position. Volume flow rate of exhaust gasses at the header pipe inlet was calculated based on engine parameters and operating speed. The average pressure values with respect to physical time were measured and graphed across the header pipe inlet cross-section. Eight different header pipe and exhaust expansion chamber combinations were modelled, tested, and results compared at low, medium and high engine speeds. It was found that the presence of exhaust expansion chamber tends to dampen the amplitude and decrease the frequency of pressure oscillations generated at the opening of the exhaust valve(s). Observations show that the addition of an expansion chamber as per design of performance-oriented motorcycles helps to decrease the negative effect of engine tuning while also dampening the positive effect.

Numerical investigation of effects on premixed hydrogen/air flame propagation in pipes with different contraction or expansion angles

Numerical simulations of premixed hydrogen-air flame propagation in a pipe with different contraction or expansion angles are carried out in this study. The effects on the flame propagation characteristics are investigated, including flame shape, the speed of flame front and overpressure. Results show that the flame propagation at different contraction angles experiences 6 flame stages: spherical flame stage, finger-shaped flame stage, stage of flame front touching the sidewalls, classic tulip flame stage, dissipation stage of tulip flame and its re-formation stage. The formation of tulip flame and the following stages are promoted by the contraction structure. Meanwhile, the development of the flow and pressure fields near the contraction are analyzed and it is found that the paraclinical effects induced by the contraction angle enhance the tulip re-formation. In the sudden expansion pipes, a triple flame stage appears in the pipes. The flame front remains relatively static for a period of time. However, the flame would continue to propagate when the expansion angle becomes larger and the flame propagation distance in the ducts increased obviously with the larger expansion angle. Baroclinic effect can inhibit the intensity of the vortex in the flow field, and hence weaken the forward transport of fuel. This inhibit effects decrease with the expansion angle becomes larger. The results of this study have implications concerning designs for pipe geometry of hydrogen and may help get better hydrogen transportation.

Heat transfer in turbulent nanofluids: Separation flow studies and development of novel correlations

Convective heat transfer plays a significant role in numerous industrial cooling and heating applications. This method of heat transfer can be passively improved by reconfiguring flow passage, fluid thermophysical properties, or boundary conditions. The broader scope of nanotechnology introduced several studies of thermal engineering and heat transfer. Nano-fluids are one of such technology which can be thought of engineered colloidal fluids with nano-sized particles. In the present study, turbulent forced convection heat transfer to nanofluids in an axisymmetric abrupt expansion heat exchanger was investigated experimentally. During heat transfer investigation, the functionalized multiwalled carbon nanotubes (MWCNT-COOH), polycarboxylate functionalized graphene nanoplatelets (F-GNP), SiO2 and ZnO water-based nanofluids were used. The convective heat transfer coefficient of fully developed turbulent flow of nanofluids flowing through an abrupt enlargement with the expansion ratio (ER) of 2 was experimentally determined at a constant wall heat flux of 12,128.56 W/m2. The experiments were conducted at the Re ranges of 4000–16,000. The observed Nusselt numbers were higher than in the case of fully developed pipe flow indicating the level of the turbulent transport is high even though the recirculating velocities were a few percentages of the bulk mean velocity. The effect of Reynolds number and nanofluid’s volume concentration on heat transfer and friction losses were studied, where all the results reveal that with the increase of weight concentration and Reynolds number, the local Nusselt number enhanced at the increment of axial ratios in all the cases showing greater heat transfer rates than those of the base fluids. Comparison between the examined four types of nanofluids, show that the carbon-based nanofluids have a greater effect on enhancing heat transfer (33.7% and 16.7% heat transfer performance improvement for F-GNP and MWCNT nanofluids respectively at 0.1 wt% concentration) at the downstream of the sudden expansion pipe. There is no reported work dealing with the prediction of the local Nusselt number at the distance equivalent to the axial ratio and flow through sudden expansion. So far, two excellent correlations for the Local Nusselt number are proposed with reasonably good accuracy. Furthermore, a new correlation is developed for the average Nusselt number.

Pressure recovery and acceleration length of gas-solid suspension in an abrupt expansion – An Eulerian-Eulerian approach

The present study based on the Eulerian-Eulerian frame work, reports the role of inter-particle and particle–wall collisions in conjunction with pertinent parameters in an abrupt expansion pipe. The parameters that were investigated are the pressure recovery and the acceleration length. The solid loading was considered between 2 and 10, within which the roles of collisions were found to be prominent. The collisions are identified as the sole mechanism responsible for the lateral dispersion of the relatively coarse particle (400–1000 µm) into the recirculation zone. An increase in the solid loading (from 2 to 10) and the Reynolds number increases the pressure recovery and the acceleration length. On the other side, the lighter (1020 kg/m3) and relatively small sized particles (400 µm) are also responsible for the same. With an increase in the area ratio up to a critical value ≈9.97 the pressure recovery increases and then reduces.

Влияние экспандирования труб на перераспределение остаточных напряжений после формовки

In the factory, pipes for trunk oil and oil product pipelines are obtained by molding and welding. To ensure a cylindrical shape and reduce technological residual stresses, expansion technology is used. Pipe expansion causes a significant change in the values of residual deformations and stresses. The article presents both the calculation results and graphs regarding stress and strain distribution during bending of the stock and their redistribution after expansion. Based on the calculation results, the final total values of residual stresses and residual deformations caused by bending and expansion were stated to be important components of the stress-strain state observed in pipelines being operated under cyclic loading, as well as those used in assessing how degradation affects the ductility of the pipe material. These factors were concluded as being reasonably taken into account when performing verification calculations regarding long-running pipelines if, based on their diagnostics and analysis, their state does not meet modern strength requirements.

An improved prediction model for corner stall in axial compressors with dihedral effect

Corner stall predictions are important and difficult in axial compressors. However, all of the prediction models have proved to be ineffective for advanced compressor blades, which tend to use the combined sweep and dihedral. As for the prediction parameter DL, although it effectively modeled the effects of the adverse pressure gradient and secondary flow, it failed to predict the corner stall of curved blades because the model failed to consider the intersection of the boundary layer at the corner region. In this paper, the shape factor gradient Ψ of the boundary layer at the corner region was investigated by numerically studying specially shaped expansion pipes under different adverse pressure gradients. The improved prediction parameter DJ was presented based on the model of Ψ and the circumferential pressure gradient ξ. A comparison of the critical range of the prediction parameters DL and DJ was investigated using the NACA65 cascade database, which was established by a numerical method. Then, the stall criterion was validated according to the experimental results of various test facilities with different blade geometries and experimental conditions. The results show that the improved prediction parameter is able to predict the corner separation/stall flows and is in good agreement with the experimental results for axial compressors with three-dimensional designed blades.

Integrating blue-green and grey infrastructure through an adaptation pathways approach to surface water flooding.

A range of solutions to future flood risk are available ranging from blue-green infrastructure (BGI) as commonly incorporated in sustainable drainage systems (SuDS) to traditional grey infrastructure (e.g. pipe networks, storage tanks, flood walls). Each offers a different profile with respect to costs, flexibility of implementation and the ability to deliver a range of wider benefits beyond their flood protection function. An important question that must be addressed when considering these approaches is what is the most suitable mix of grey and blue-green solutions to urban flooding at any location and at any future time? This paper uses an adaptation pathways approach to compare a range of alternative options to deal with current and expected future flood risk in part of a London borough. Solutions considered separately and in combination include grey pipe expansion, bioretention cells, permeable pavements and storage ponds. A methodological framework combines a range of existing tools to develop, assess and characterize each pathway, including a storm water management model (SWMM), a SuDs opportunity selection tool, an adaptation pathway generator and the CIRIA B£ST tool for monetizing multiple benefits. Climate change is represented by the UK Water Industry Research method for establishing future rainfall intensities for sewer and BGI design. The results showed that by extending the way in which adaptation pathways are compared and evaluated through the wider consideration of multiple benefits there is a trade-off between deferring interventions until they are needed for flood risk mitigation and delivering the multiple benefits associated with interventions so that performance thresholds do not need to be met before introducing new options. The relative contribution of each option's capital and operation and maintenance costs has implications on when the option is implemented as well as the rate of implementation. The monetization of the multiple benefits associated with each pathway shows that their economic co-evaluation alongside infrastructure costs can change the preference for one pathway over another. This article is part of the theme issue 'Urban flood resilience'.

Finite Element Analysis of Tube End Forming and Process Design

Compared with forging and extrusion processes, tube end forming includes various forming methods, such as pipe expansion, bending, bulging, folding, shrinking and profile processing. Therefore, research and development of pipe processing and forming are of great importance in the industry. In this study, the authors used the finite element analysis software DEFORM to analyze the end deformation behavior of the single pass forming. The deformation behavior of the pipe end, load curve and formability are discussed. The single-pass forming die design enables the pipe ends to be formed into two different shapes. By reducing the processing procedures with the geometric design of the dies, the processing advantages of single pass forming are achieved.

Effect of Heat Treatment on the Characterizations of Functionally Graded Al/Al2Cu Fabricated by Horizontal Centrifugal Casting

In the present paper, in situ centrifugal casting as an advanced material processing method is proposed to fabricate Al–26 wt% Cu–7wt% Si FG pipe with the density of 3.5 g/cm3 and with the wear resistance of 1.85064 × 10−16 m3/mN. The casting mould is preheated to approximately 200 °C to avoid chilling effects, segregation, porosity and compensation of the shrinkage of the alloy during the casting. Variations of the Al2Cu-based content are investigated by the field emission scanning electron microscopy (FESEM) in conjunction with image analyser software (MATLAB code). The microstructure results show that the Al2Cu content smoothly decreases from the outer layer containing 44.4 vol% to inner layer containing 37.8 vol% due to the difference in density of constituent phases and elements. The graded properties such as Vickers hardness, coefficient of thermal expansion and mechanical properties of the present FG pipe are measured to show the significant dependence of the microstructure. It shows that Vickers hardness value gradually decreases from the outer with 331.3 HV to the inner with 141.0 HV. Furthermore, the heat treatment of the samples is conducted in boiling water (100 °C) for 4.5 h to promote the formations of new Al2Cu particles into the α-Al phase and consequently improve the hardness and CTE of the FG pipe.

Design of an Experimental Device for Simulation of Pipeline Expansion

This article describes the design of an experimental device for simulating pipe expansion. The device consisted of various variants of compensating elements and types of piping materials. Based on this, a 3D model was developed, together with numerical design calculations of compensators. Subsequently, a more complex analysis was performed by using the CAE Pipe calculation program, which performed calculations of dilatations, forces at fixed points and stresses in the pipeline.

An experimental and numerical investigation of CO2 corrosion in a rapid expansion pipe geometry

A combined experimental and numerical methodology for accurately translating Rotating Cylinder Electrode (RCE) CO2 corrosion data to complex pipe flow geometries is presented. Computational Fluid Dynamics (CFD) simulations are used to determine the local variation in mass-transfer coefficient throughout a rapid expansion (as an example geometry). An empirical correlation between mass-transfer coefficient and corrosion rate derived from RCE experiments is then integrated into the CFD model to predict the variation in corrosion rate throughout the fitting. Electrochemical and mass loss corrosion experiments using carbon steel coupons integrated into a 3D printed rapid expansion within a flow loop validate the approach.

Effect of Heat Treatment on the Properties of AlCu26Si8

ABSTRACTIn this paper, in situ centrifugal casting was proposed to fabricate Al-26 wt.% Cu-7.8 wt.% Si FG pipe with the density of 3.5 g/cm3 and also the wear resistance of 0.0241g/mm2. The casting mould is preheated to approximately 200°C to avoid chilling effects, segregation, porosity and compensation of the shrinkage of the alloy during the casting. The microstructure results show that the Al2Cu content smoothly decreases from the outer layer to inner layer. Vickers hardness, coefficient of thermal expansion (CTE) and mechanical properties of the present FG pipe are measured to show the significant dependence of the microstructure. Furthermore, the heat treatment of the samples are conducted in boiling water (100°C) for 4.5 h to promote the formations of new Al2Cu particles into the α–Al phase and consequently improve the hardness and CTE of the FG pipe.

Cost reduction of solar thermal plants by advanced thermal-hydraulic design methods

Software programs for thermodynamic systems modelling and simulation, e.g. Polysun®, are well established and widely used. By comparison, there are few tools available for the dimensioning of pipe networks, pumps and expansion vessels. Furthermore, it has not been possible to prove operational safety numerically. This gap is closed by the software tools HYDRA and THD which are introduced in this article. HYDRA is used to design the pipe network of large thermal solar plants. THD allows the dimensioning of solar plants up to approximately 100 m2 collector area, including proof of venting capabilities and proof of stagnation safety.

Effect of Axial Compression and Wet Collapse Loads on Torsional Response of Flexible Pipe

Flexible pipes connect the two critical systems of the floating production platform and underwater production, which play an important role in the transportation of oil and gas as well as water injection. However, flexible pipes are often subjected to multiple loads that threaten their stability in the service process. In this study, a model of a flexible pipe containing practical cross section in all layers is established to study the effects of axial compression and wet collapse loads on clockwise and anticlockwise torsional responses. The results of calculation show that the axial compression and radial expansion of the flexible pipe are caused by the axial compression load, which reduces clockwise torsional stiffness. The wet collapse load induces the bending deformation of the flexible pipes in clockwise and anticlockwise torsion, where the bending deformation of clockwise torsion is significantly affected by the change in the Young’s modulus of the tensile armor layers. This study shows that clockwise torsional stiffness is small and exhibits a trend of axial compression. Clockwise torsion has poor stability in combination with axial compression and wet collapse loads, respectively. Therefore, to prevent instability in flexible pipes, clockwise torsion load, or which coupled with axial compression and wet collapse load, should be avoided.

Direct numerical simulations of laminar and transitional flows in diverging pipes

PurposeFluid flows in pipes whose cross-sectional area are increasing in the stream-wise direction are prone to separation of the recirculation region. This paper aims to investigate such fluid flow in expansion pipe systems using direct numerical simulations. The flow in circular diverging pipes with different diverging half angles, namely, 45, 26, 14, 7.2 and 4.7 degrees, are considered. The flow is fed by a fully developed laminar parabolic velocity profile at its inlet and is connected to a long straight circular pipe at its downstream to characterise recirculation zone and skin friction coefficient in the laminar regime. The flow is considered linearly stable for Reynolds numbers sufficiently below natural transition. A perturbation is added to the inlet fully developed laminar velocity profile to test the flow response to finite amplitude disturbances and to characterise sub-critical transition.Design/methodology/approachDirect numerical simulations of the Navier–Stokes equations have been solved using a spectral element method.FindingsIt is found that the onset of disordered motion and the dynamics of the localised turbulence patch are controlled by the Reynolds number, the perturbation amplitude and the half angle of the pipe.Originality/valueThe authors clarify different stages of flow behaviour under the finite amplitude perturbations and shed more light to flow physics such as existence of Kelvin–Helmholtz instabilities as well as mechanism of turbulent puff shedding in diverging pipe flows.

Experimental and Numerical Study of the Flow and Heat Transfer in a Bubbly Turbulent Flow in a Pipe with Sudden Expansion

The flow patterns and heat transfer of a downstream bubbly flow in a sudden pipe expansion are experimentally and numerically studied. Measurements of the bubble size were performed using shadow photography. Fluid phase velocities were measured using a PIV system. The numerical model was employed the Eulerian approach. The set of RANS equations was used for modelling two-phase bubbly flows. The turbulence of the carrier liquid phase was predicted using the Reynolds stress model. The peak of axial and radial fluctuations of the carrier fluid (liquid) velocity in the bubbly flow is observed in the shear layer. The addition of air bubbles resulted in a significant increase in the heat transfer rate (up to 300%). The main enhancement in heat transfer is observed after the point of flow reattachment.

Effect of evaporating droplets on flow structure and heat transfer in an axisymmetrical separated turbulent flow

The results of a numerical investigation of the effect of droplets’ thermophysical properties on the flow structure, turbulence, and heat transfer in a two-phase mist flow in a sudden pipe expansion are presented. Predictions are carried out for droplets of water, ethanol, and acetone for initial droplet diameters varying in the range d1 = 1–100 μm. The RANS approach is used to simulate a gaseous phase, and the motion and heat transfer of a dispersed phase are computed using the two-fluid Eulerian model. Gas phase turbulence is predicted using the model of Reynolds stress transport modified for the case of particle presence. It is shown that the addition of droplets leads to a significant increase in heat transfer (up to 50% at ML1 = 0.05) in comparison with a single-phase separated flow. Heat transfer enhancement with the use of ethanol droplets is slightly higher than the corresponding value for water droplets (by approximately 10–20%). The length of the region of intensified heat transfer is maximal for water droplets, while it is minimal for acetone droplets. The effect of heat transfer intensification and suppression of carrier gas phase turbulence is minimal for the acetone droplets.

Research of heavy wall X65MOS submarine pipeline steel key process strategy

In recent years, there has been development of several significant pipeline projects for the transmission of oil and gas from deep water environments. The production of gas transmission pipelines for application demands heavy wall, high strength, good lower temperature fracture toughness, low yield ratio and good corrosion resistance. To overcome the difficulties of producing excellent performance in heavy wall X65MOS pipe Shougang Steel Research in cooperation with the Shougang Steel Qinhuangdao China (Shouqin) 4.3m heavy wide plate mill research was conducted.This paper describes the background, composition design, key process strategy to produce excellent performance in heavy wall X65MOS plate. The importance of recrystallized rolling process, the tensile property change during pipe making and the corrosion resistance change by “pre-stretching + bend” deformation simulate pipe making in the lab will be discussed. The results showed the per pass reductions during recrystallized rough rolling should be increased in a steady fashion, with special emphasis on the reduction of the final two roughing pass prior to the intermediate hold (transfer thickness for finishing) should be more than 20%. The tensile properties change rule and the reasonable pipe expansion process should be determine during pipe making. The crack length ratio(CLR) internal control criteria of the plate should be less than 6%, it helps to ensure the HIC performance of the pipe can meet the technical specification(CLR≤15%).