Pipe Work Research Articles

A comparative study of different heat transfer enhancement mechanisms in a partially porous pipe

The effect of porous material position on the heat transfer inside a pipe working in a turbulent regime is studied here to obtain a detailed understanding of the heat transfer enchantment mechanisms in different porous substrate positions. To this end, an in-house Fortran code is developed to solve the governing equations using the finite volume method and SIMPLE algorithm. Turbulent flow in porous media is modeled using a modified version of k–ε model. The flow field and heat transfer inside the partially filled pipe are investigated for the two cases of central and boundary configurations. The porous and flow characteristics including Reynolds number, Darcy number, the conductivity ratios of solid to fluid and the thickness of inserted porous layer are varied and the heat transfer performance is studied in different cases. It is observed that two entirely different phenomena enhance the heat transfer in central and boundary configurations. While the channeling of fluid between the porous media and the pipe wall highly affects the heat transfer performance in the former, the thermal conductivity of porous media plays a highly critical role in the latter configuration. It is shown that, for the same filling ratio, inserting the porous layer at the core of the pipe is more effective than placing it at the wall. Investigating porous materials with different solid conductivities revealed that covering the pipe wall with a porous material is justified only for solid matrixes with high thermal conductivities.

설계변경으로 인한 기계설비 배관공사 적산작업의 효율화 방안

At construction sites, design changes occur frequently for various reasons. Design changes during construction need to be carried out with a fast-track method because it must be performed prior to construction. Among various design change works of construction, the item that requires the most work time is cost estimation. Among various fields, mechanical facility is the one with the highest number of items. In mechanical facility field, the piping work has the highest number of items. This work intends to present an efficient plan for cost estimation of piping work due to design changes. Prior research, domestic standards, and international standards were investigated. Cost estimation methods of mechanical piping work by existing drawing and BIM were compared and analyzed. When calculating the quantity by BIM, a lot of time is required for converting the existing 2D drawing to BIM. On the other hand, direct calculation method required relatively less time because there were many similar parts for pipe connection. There was a difference of about 8% in the price depending on whether the piping premium was applied and whether piping parts were included in the piping length.

Experimental and numerical investigation on destructive effect of gas pipeline buried in silty clay under surface explosion

Identifying the damage effects of buried multiple-operating-pressure gas pipelines subjected to various magnitude blasting load is a prerequisite for pipeline safety assessment. In this study, the dynamic response and damage effect are assessed by a combination of both field experiments and numerical simulation. It is indicated that the error between the numerical calculation and the field measured data is small and the reliability of the model is high. The dangerous section of the whole pipeline lies directly below the explosion source. The peak particle velocity (PPV) and the peak particle effective stress (PES) on the explosion-prone side of the section are the largest. Moreover, the PPV and PES increase with the increase of the working pressure of the pipeline. Results show that the empty pipe with no working pressure is the safest state among various pipe working state. There is a certain functional relationship among the explosive charge on the ground surface, working pressure, and PES of the pipeline.

Experimental study of thermoelectric cooler box using heat sink with u-shape heat pipe and methanol working fluid

Thermoelectric refrigeration system is considered environmentally friendly because it does not use refrigerants which have huge potential damaging the ozone layer. In this experimental work, u-shape heat pipe with heat sink was charged with methanol working fluid with different filling ratios to observe its effect on the thermoelectric performance. The cooler box has 240 mm x 180 mm x 130 mm of inner dimension. 37.3 watt DC power supply supplied constantly to the thermoelectric module to performed cooling action. The result shows that methanol with 45% and 55% filling ratios has the maximum COP about 0.03881 and 0.03885 respectively. This filling ratio also provides for a lower cabin temperature and temperature difference between the cold and hot thermoelectric sides.

Phosphate Dosing in Drinking Water Distribution Systems Promotes Changes in Biofilm Structure and Functional Genetic Diversity.

Water utilities treat drinking water by adding phosphate to prevent metal dissolution from water pipe work systems and particularly lead poisoning. Phosphate can be a limiting nutrient for microbial biofilms in DWDS, yet its effects on these microbial consortia are not well understood. This research presents results from phosphate dosing experiments using a real scale chlorinated DWDS, comparing standard phosphate concentrations of United Kingdom drinking water (1 mgP/L) with a double dose (2 mgP/L) commonly used in plumbosolvency treatment. Biofilm development during phosphate treatment experiments was monitored using a holistic approach by combining metagenomics analysis, flow cytometry and SEM characterisation. The increase of phosphate levels in drinking water, reduced biofilm cell numbers and promoted the presence of poorly distributed biofilms on inner pipe surfaces. Metagenomics analysis using genetic markers (16S rRNA and ITS2) showed that phosphate influenced biofilm community structure, particularly fungal composition. Whole metagenome sequencing showed that phosphate enrichment favoured the presence of sequencing reads associated to ATPases, ion transporters and DNA-interacting proteins, whilst reads associated to nitrogen metabolism were predominant in control samples. This research brings new knowledge regarding the influence of phosphate treatment on the composition and structure of biofilms within DWDS, and the implications that this might have for the management of these systems.

Influence of the geometrical parameters and particle concentration levels of hybrid nanofluid on the thermal performance of axial grooved heat pipe

In the present study, a numerical model is developed to maximize the thermal performance of axial grooved heat pipe (AGHP) working on CeO2 + MWCNT / water based hybrid nanofluid (HNF). The effects of a wide range of volume concentration (0.25%−1.50%) at different operating temperatures (55 ℃−75 ℃) are analyzed to maximize the thermal performance of AGHP. The current numerical work aims at finding the heat transport capacity, Qmax, and total thermal resistance, Rtotal, of AGHP with acceptable accuracy by validating it with the past experimental studies. It has been observed that the highest Qmax is achieved at 1.25% of the volume concentration of HNF for each operating temperature. The novel HNF based AGHP shows an enhancement of 61.27% in the heat transport capacity and a reduction of 30% in the total thermal resistance compared to the water-based AGHP. The study is further extended by incorporating the effects of geometrical parameters on AGHP’s thermal performance. Three geometrical parameters are considered in this study, namely groove height (hg), number of axial grooves (N), and their inclination angle (α). A total of 128 combinations of N, hg, and α have been analyzed to optimize Qmax and Rtotal. The maximum thermal performance of AGHP is achieved at N = 28, hg = 1.3 mm, and α = 76°, where the Qmax = 78.5 W and Rtotal = 0.054 °C/W.

Multiphase flow and heat transfer characteristics of an extra-long gravity-assisted heat pipe: An experimental study

The exploitation of deep geothermal energy has created a great demand for super-long distance heat transportation technology. As one of the most highly-efficient heat transfer devices, the super-long gravity-assisted heat pipe is promising to achieve this heat transportation. The performance of the super-long heat pipe is related to the multiphase flow status inside, the details of which are yet unknown. In this paper, a systematic experimental study on the multiphase flow regimes and the performance of an extra-long heat pipe was conducted. The experimental heat pipe is 40 m in length, 7 mm in diameter, which mimics the major geometric characteristic of the super-long heat pipes that can be practically used for geothermal heat extraction. Thermal performance and surface temperature of the extra-long heat pipe using water, ethanol or acetone as working fluid were measured and analyzed. Particular focus was placed on correlating the heat transfer performance of the heat pipe with the multiphase flow regime inside it. It was found that the extra-long heat pipe works in the following four different flow regimes successively with the increase in inflow heat: (1) nucleating pool boiling regime; (2) geyser boiling regime; (3) evaporating film boiling regime; and (4) overheated boiling regime. The thermal performances of extra-long heat pipe are significantly affected by the flow regimes, while the transition between these flow regimes is influenced by the properties of working fluid, the fluid fill height, and the heat load. It is found that the heat pipe working in the evaporation film boiling regime shows the best thermal performance and the heat pipe using water as working fluid is more suitable for relatively high heat load use. The reachable maximum axial heat fluxes for the water, ethanol, and acetone heat pipes are found to be about 6.5 × 106, 2.21 × 106, 2.08 × 106 W·m−2, respectively. These characteristics of heat transfer and multiphase flow provide very useful hints for the design and development of super-long geothermal heat pipes.

The Impacts of Nanoparticle Concentration and Surfactant Type on Thermal Performance of A Thermosyphon Heat Pipe Working With Bauxite Nanofluid

ABSTRACT Heat pipes are one of the most preferred equipment because they have a variety of superior specifications. In this paper, the improvement of heat transfer properties of a thermosyphon heat pipe that was filled with bauxite nanofluid was experimentally investigated for different nanoparticle concentrations (1%, 2%, and 4%) and surfactant types (Triton X-100 and Sodium Dodecyl Benzene Sulfonate). Bauxite nanoparticles at different concentrations were utilized for the preparation of nanofluid suspensions. Different kinds of surfactants were also doped into the prepared nanofluid suspensions to show off how a surfactant affects the thermophysical properties of the nanofluid. The experiments were done under several heating powers and various mass flow rates of the cooling water circulating on the evaporator section. Temperature distributions both upon the evaporator and the condenser sections were recorded via 8 different K type thermocouples. Cooling water inlet and exit temperatures were also recorded and utilized for theoretical calculations. For doing an experimental comparison, thermal efficiency and resistance of the thermosyphon heat pipe were determined both for distilled water and prepared nanofluid suspensions. Moreover, contact angle-wettability analysis was carried out to determine how nanoparticles affect the surface tension. The encountered problems during the tests were addressed and discussed. The obtained experimental data illustrated that the thermosyphon heat pipe efficiency was increased by up to 20.9% with the usage of a 2% (mass) concentration of bauxite nanofluid and an anionic surfactant. The maximum enhancement in heat pipe’s thermal resistance was found as 24.3%, through bauxite nanofluid usage.

Experimental investigation and analytical prediction of a multi-channel flat heat pipe thermal performance

Recently, multi-channel flat heat pipes have been developed to improve the heat recovery from flat surfaces, such as solar panels and batteries. In this paper, the thermal performance of a multi-channel flat heat pipe is experimentally investigated and analytically predicted. The multi-channel heat pipe studied transmits heat from silicone flat heaters to a water flow circulating inside a cooling manifold. The manifold heat sink is a flat aluminium surface comprising channels in which water recovers thermal energy by forced convection. The impact of the water flow rate on the working temperature of the heat pipe is investigated. To predict the performance and working temperature of the multi-channel flat heat pipe, a theoretical model has been developed. The thermal model considers the two-phase heat transfer in a multi-channel heat pipe geometry. It is shown that the heat pipe working temperature decreases with the water flow rate as a result of a reduced forced convection resistance of the manifold. Finally, the analytical multi-channel flat heat pipe model developed is compared with experimental data. It is shown that the thermal model, considering both cooling manifold and the multi-channel heat pipe geometry, is able to predict the heat pipe working temperature evolution within 7%.

Analisis Kekuatan Flange Valve Akibat Pengaruh Bolt Torque pada Kondisi Pressure dan Temperature Berbeda dengan Metode Finite Element Analysis

Sistem penyambungan pipa yang terhubung dengan valve (katup) menggunakan sambungan flange. Hal ini bertujuan untuk memudahkan memasang atau melepaskan sambungan pada saat diperlukan. Sistem penyambungan ini meliputi sambungan pipa ke fitting, valve, equipment, atau bagian lainnya yang merupakan bagian terpisah dalam sistem pemipaan. Analisis kekuatan flange pada ball valve 4 inch ANSI 300 bertujuan untuk mengetahui dan memastikan bahwa flange memiliki kekuatan dan aman pada saat lepas pasang akibat pengaruh Bolt Torque. Selain itu, untuk memastikan sambungan tidak bocor pada saat dilalui fluida. Kombinasi utama antara tekanan internal, aksial dan pembebanan termal perlu dipertimbangkan. Analisis kekuatan flange menggunakan metode Finite Element Analysis (FEA) dengan bantuan software Solid works. Analisis kekuatan flange menggunakan metode “Flange as weakest part philosophy” yaitu full rating yang dipakai bila nilai pressure-temperature tertentu pada ASME B16.5 yang diambil untuk Tekanan Kerja Maksimum yang diijinkan atau Maximum Allowable Working Pressure (MAWP) pada sistem perpipaan. Dari hasil analisis FEA, diperoleh bahwa flange pada ball valve 4 inch ANSI 300 memenuhi syarat sesuai dengan MAWP pada temperatur dan tekanan berbeda. Nilai safety factor juga menunjukkan bahwa flange aman pada saat proses kerja pemipaan.

Investigating the effect of pressure on a vertical two‐phase upward flow with a high viscosity liquid

AbstractThis article presents void fraction and pressure gradient data for sulfur hexafluoride (SF6) with gas densities of 28 and 45 kg/m3 and oil (with viscosity 35 times that for water) in a 127 mm diameter pipe. The superficial velocities of gas ranged from 0.1 to 3 m/s and those for liquid from 0.1 to 1 m/s, respectively. Measurements of void fraction data were recorded using a capacitance wire mesh sensor (WMS) system, which permits the 3D visualization of the flow patterns. All the data were obtained with a data acquisition frequency of 1,000 Hz. A differential pressure transducer was used to measure the pressure drops along the length of the pipe. The WMS provide time and cross‐sectionally resolved data on void fraction and from an analysis of its output, flow patterns were identified using the characteristic signatures of probability density function (PDF) plot of time series of void fraction. The PDF plots showed the single peak shapes associated with bubbly and churn flows but not the twin‐peaked shape usually seen in slug flows. This confirms previous work in larger diameter pipes but with less viscous liquids. For the bubble and churn flows investigated, the pressure gradient was observed to decrease with an increase in gas superficial velocity. Nevertheless, there was an insignificant observed effect of pressure on void fraction below certain transitional flow rates, the effect however became significant beyond these values. In the present work, wisps appear to be smaller, which might be due to the different fluid properties of the working fluids employed. In addition, wisps are easily revealed as long as there is a transition between churn and annular flows regardless of the pressure. Experimental data on void fraction and pressure gradient are compared against existing data. Reasonably good agreements were observed from the results of the comparison.

Flow Induced Vibration (FIV) Research of Oil and Gas Process Piping System

Piping systems in crude oil production facilities tend to handle high pressure and high velocity flowing fluid at certain flow rate limit resulted in generation of turbulence flow. This turbulence can generate high levels of broad band kinetic energy which can propagate through the system. Even though the energy is distributed across a wide frequency range, most of the excitation is concentrated at low frequency (typically below 100 Hz); the lower the frequency, the higher the level of excitation from turbulence. This leads to excitation of the low frequency vibration modes of the pipe work, in many cases causing visible motion of the pipe and, in some cases, the pipe supports, and this phenomenon is called Flow induced vibration (FIV) and if excessive can result in fatigue failure. This objective of the paper is to identify potential sources of FIV on piping by predicting the Likelihood of failure (LOF) and advising on the necessity for system modifications to minimize or eliminate any FIV induced piping or line failure from Flow Induced Turbulence. These are done by conducting a FIV assessment for piping systems in oil production facilities which are potentially affected by vibration due to both process conditions and mechanically induced pipework vibration. Another scope of this paper is to apply the recommendation action required in order to reduce the likelihood of failure by changing pipe diameter and/or wall thickness by looking at the fluid structure interaction (FSI). By changing the outer diameter and the wall thickness of the pipe, the formation of the excitation in flow regime and the presence of the critical flow disturbance will decrease. These changes are able to reduce the formation of FIV thus increasing the lifespan of the piping system

Risk level Assessment of the Desalter and Preflash Column of a Nigerian Crude Distillation Unit

A study of operability and assessment of the safety level of a crude distillation unit in a Nigerian refinery has been carried out. In a crude distillation unit of a refinery, the desalter and preflash column, as well as their associated pipe works and pumps, are considered to have high-risk factors that can present operability problems and possibly hazardous conditions. Applying the HAZOP methodology, a total of 25 guide words were suitably applied on 4 nodes to study the possible deviations that may occur. The 89 causes of these deviations identified in the study could be classified under human errors and equipment malfunctioning. From the nature of the 46 consequences identified, the plant is likely to experience more of operability problems and less of deadly hazardous scenes. Suitable recommendations that will improve the operability and safety levels of the plant were however presented in the study and presented in tables. If the 61 recommendations given in this study can be incorporated into the design with the few safeguards already present in the original design of the plant, the operability problems of the plant will be greatly minimized and safety level will improve drastically.

Assessment of Offshore Piping Composite Repair Technology for Life Extension Program Case in Pertamina Hulu Energy West Madura Offshore

The pipe work repair method such as clamps and pipe connector as the use of metallic repair component have been used for maintenance and repair application in oil and gas industry and cover the most common types of defect to pressurize system like internal and external corrosion and also cover situations where the damage is severe. On the other hand with a process safety precausion and production concern, in oil and gas facility the use of metallic repair is very challenging and most of the time will come as last option scenario. Composite repair which are now increasing in application to pipe repair situations may come as a solution. This paper provides assessment of offshore piping composite repair for life extension program of pressure system in West Madura Offshore. Assessment come to a conclusion that the composite repair at field PHE WMO which operate on envelop of 700 psi and temperature range of 20°C-80°C are still in good condition and retain the integrity of the asset, from where then the repair is considered to extent its lifetime.

Computational Fluid Dynamics (CFD) Simulation of Sand Particle Erosion in Turbulent Gas Fluid Flow in Vertical-Horizontal Elbow

Erosion of sand particles is one of the serious problems in the oil and gas production industry. There is strong evidence that most wells now produce increased sand as the major oil and gas production declines. This is a widespread problem as it can affect the rate of production as we age the asset. Accurate erosion prediction, especially elbow, can be used to improve pipe work design, inspection area, operating limit and others. In this study, we used CFD modeling in ANSYS Student Version 19.0 application to predict erosion in turbulent gas flow with the variation of sand particle size and fluid velocity. The results obtained were erosion profile and erosion rate in pipe elbow compared with the experimental results. Simulation results show that CFD able to predict erosion rates well for 300 μm particle size with error 14.75% compare 150 μm particle size with error 271.5%. Formed erosion profile in the form of 'V' scar on the vertical - horizontal pipe elbow.

Vacuum vessel Upper Port design assessment of the European DEMO

The present work focuses on the design assessment of the DEMO Upper Port. The size of the upper port is defined by the available space in between the toroidal field coils and the required space to integrate a thermal shield between the vacuum vessel (VV) port and the coils. Since the large breeding blanket (BB) segments will require periodic replacement via the upper vertical ports the space inside the upper port needs to be maximized. For this reason the optimization and verification of the upper port design is a critical aspect in the development of DEMO project. The work here presented investigates the possibility to have an upper port with single walled sidewalls to increase the space available inside the port for the integration of pipe work and to allow the handling of the BB segments. The work carried out evaluates the feasibility of the design solution from the structural and thermal point of view verifying the upper port structure against nuclear heating, in-vessel pressure, and electromagnetic loads due to a toroidal field coil fast discharge and plasma disruptions according to nuclear codes.

Evaluation of stress relaxation cracking susceptibility in Alloy 617 for advanced USC boilers

In this study, the stress relaxation cracking susceptibility of Alloy 617, which is a candidate material for advanced ultra-supercritical (A-USC) power plant pipe work, was evaluated. In order to evaluate the effect of aging and grain size on stress relaxation cracking susceptibility, materials aged at 700 °C and coarse grain materials heat treated at 1200 °C for 1 h, 1225 °C for 2 h, 1250 °C for 3 h were tested in addition to as-solution-annealed materials. A three-point bending test with notch placed at the center of each specimen was used for the examination. The test results showed that only the aged material suffered stress relaxation cracking. The time-to-crack tends to be shortened when initial strain in the test is increased. This suggests that higher residual stress in the weldment would increase the risk of stress relaxation cracking. It was proposed that the larger magnitude of creep strain occurs via stress relaxation during the three-point bending test due to higher yield strength caused by γ' phase strengthening, and low ductility due to grain boundary carbides in aged materials promoted stress relaxation cracking. The critical conditions to cause crack could be estimated from the stress relaxation cracking boundary in the map of the relationship between the initial strain and the creep strain during the three-point bending test.

Theoretical analysis of the oscillating circular piston positive displacement flowmeter: II numerical solution of equations of motion and comparison with experimental data

In the first part of this paper, Morton et al. [1], we identified the forces and equations required to model the motion of the oscillating piston flowmeter. In this paper we discuss the method of solution, and the computational procedure for modelling the dynamic behaviour of the meter. We have, then, compared the model results with experimental data for variation in: angular velocity, vertical movement and pressure losses. We consider the agreement for variation in the following parameters: flow rate, piston mass, surface coating, lubrication holes, slots in piston skirt, length of up- and downstream pipe work, fluid viscosity and fluid density. We also compare the theory with data from two other sizes of meter. The predictions from the model are generally very accurate, although there is still potential to refine the model and increase further our understanding of the forces which contribute to the motion.

Integrating a Procurement Management Process into Critical Chain Project Management (CCPM): A Case-Study on Oil and Gas Projects, the Piping Process

Engineering, Procurement, and Construction (EPC) of oil and gas megaprojects often experience cost overruns due to substantial schedule delays. One of the greatest causes of these overruns is the mismanagement of the project schedule, with the piping works (prefabrication and installation) occupying a majority of that schedule. As such, an effective methodology for scheduling, planning, and controlling of piping activities is essential for project success. To meet this need, this study used the Critical Chain Project Management (CCPM) to develop a piping construction delay prevention methodology, incorporating material procurement processes for EPC megaprojects. Recent studies indicate that the traditional scheduling method used on oil and gas mega projects has critical limitations regarding resource scarcity, calculation of activity duration, and dealing with uncertainties. To overcome these limitations, the Theory of Constraints-based CCPM was proposed and implemented to provide schedule buffers management. Nonexistent in literature, and of critical importance, is this paper’s focus on the resource buffer, representing material uncertainty and management. Furthermore, this paper presents a step-by-step process and flow chart for project, construction, and material managers to effectively manage a resource buffer through the CCPM process. This study extends the knowledge of traditional resource buffers in CCPM to improve material and procurement management, thus avoiding the shortage of piping materials and minimizing delays. The resultant process was validated by both deterministic and probabilistic schedule analysis through two case studies of a crude pump unit and propylene compressor installation at a Middle Eastern Refinery Plant Installation. The results show that the CCPM method effectively handles uncertainty, reducing the duration of piping works construction by about a 35% when compared to the traditional method. Furthermore, the results show that, in not considering material uncertainty (resource buffers), projects schedules have the potential for approximately a 5% schedule growth with the accompanying delay charges. The findings have far-reaching applications for both oil and gas and other sectors. This CCPM case-study exemplifies that the material management method represents an opportunity for industry to administrate pipeline installation projects more effectively, eliminate project duration extension, develop schedule-based risk mitigation measures pre-construction, and enable project teams to efficiently manage limited human and material resources.

STATIC MIXERS IN FLUSHING FLUID CIRCULATION SYSTEMS OF DRILLING RIGS

The work of three static mixer designs in flushing fluid circulation systems of drilling rigs was studied taking into account the basic parameters of drilling mud. Modelling was carried out, and parametric slurry fields were obtained in the pipe work area, that is in a static mixer installation site and in the area of pipeline behind it. The following models were obtained: velocity fields, vorticity fields, turbulence intensity fields, scale turbulence fields along the travel path. Graphs of the parameters changes regarding the tube axis were plotted. The comparative analysis of patterns and curves was carried out. The rational design of static mixer for obtaining of optimum mud mixing technology features is grounded.