Multiphase Flow in Circular and Triangular Pipes: Examining Flow Characteristics, Sand Erosion and Heat Transfer Via CFD and Experimental Work

Air-water two-phase flow in circular pipes has been studied by many investigators. However, investigations of multiphase flow in non-circular pipes are still very rare. Triangular pipes have found a number of applications, such as multiphase flow conditioning, erosion mitigation in elbows, compact heat exchanges, solar heat collectors, and electronic cooling systems. This work presents a survey of air-water and air-water-sand flow through circular and triangular pipes. The main objective of this investigation is to study the potential effects of triangular pipe geometry on flow patterns, slug frequency, sand erosion in elbows, and heat transfer in multiphase flow. Firstly, twenty-three experiments were performed for horizontal air-water flow. Detailed videos and slug frequency measurements were collected through circular and triangular clear pipes to identify flow patterns and create a database for these pipe configurations. The effect of corners of the triangular pipe on the liquid distribution was investigated using two different orientations of triangular pipe: apex upward and downward and results of triangular pipes were compared to round tubes. Secondly, ultrasonic wall thickness erosion measurements, paint removal studies, and CFD simulations were carried out to investigate the erosion patterns and magnitudes for liquid-sand and liquid-gas-sand flows in circular and triangular elbows with the same radius of curvature and cross-sectional area. Thirdly, heat transfer rates for liquid flows were also simulated for both circular and triangular pipe cross-sections. Although similar flow patterns are observed in circular and triangular pipe configurations, the orientation of the triangular pipes seems to have an effect on the liquid distribution and slug frequency. For higher liquid rates, slug frequencies are consistently lower in the triangular pipe as compared to the circular pipe. Similarly, the triangular elbow offers better flow behavior as compared to circular elbows when investigated numerically with similar flow rates for erosion patterns for both liquid-sand flow and liquid-gas-sand flows. Experimental and CFD results show that erosion in the circular elbow is about three times larger than in the triangular elbow. Paint studies results validated erosion patterns and their relations with particle impacts. Finally, heat transfer to/from triangular pipes is shown to be more efficient than in circular pipes, making them attractive for compact heat exchangers and heat collectors. This paper represents a novel experimental work and CFD simulations to examine the effects of pipe geometries on multiphase flow in pipes with several practical applications. The present results will help to determine the efficiency of utilizing triangular pipes as compared to circular pipes for several important applications and field operations such as reducing slug frequencies of multiphase flow in pipes, and reducing solid particle erosion of elbows, and also increasing the efficiency of heat exchangers.

Synergetic Design of Transparent Topcoats on ITO-Coated Plastic Substrate to Boost Surface Erosion Performance

Transparent conductive films (TCFs) have received much research attention in the area of aeronautical canopies. However, bad wear, corrosion resistance and weak erosion performance of TCFs dramatically limit their scalable application in the next-generation aeronautical and optoelectronic devices. To address these drawbacks, three types of optically transparent coatings, including acrylic, silicone and polyurethane (PU) coatings were developed and comparatively investigated ex situ in terms of Taber abrasion, nanoindentation and sand erosion tests to improve the wear-resistance and sand erosion abilities of ITO-coated PMMA substrates. To elucidate the sand erosion failure of the coatings, the nanoindentation technique was employed for quantitative assessment of the shape recovery abilities under probe indentation. Results show that the PU topcoats can greatly enhance the sand erosion properties, which were superior to those of acrylic and silicone topcoats. This result can be attributed to the good toughness and self-healing properties of PU topcoats. Additionally, high hardness and good Taber abrasion properties of the ITO films and silicone topcoats did not have an obvious or affirmatory effect on the sand erosion abilities, based on their brittleness and irreparable properties under sand erosion.

Monitoring the Dynamics of Formby Sand Dunes Using Airborne LiDAR DTMs

Coastal dunes play an important role in coastal erosion risk management, where they act as a dynamic natural sea defence line. Formby coast is part of the Sefton coast in the Northwest of England and is one of the largest and most rapidly evolving sand dune systems in the UK. Such dune systems require continuous comprehensive monitoring activity to understand their dynamics. In this research, we investigate the use of airborne LiDAR digital terrain model DTMs for monitoring the dynamics of the sand dunes at Formby between 1999 and 2020. We found that the rate of elevation change for the beach and the dune areas ranges from −0.78 to 0.02 m/year and −0.92 to 0.73 m/year, respectively. The beach and the frontal dunes have had significant sand erosion, while the inner dunes gained sand during the measurement period. Vegetated areas remained unchanged due to the impact of vegetation in stabilizing the movement of the dunes. Formby beach had a volume loss of about 907,000 m3 in the last 21 years, while the dunes had a volume increase of about 1,049,000 m3 over the same period. The total volume of the entire dune system, consisting of both the beach and dune areas, remained unchanged, which indicates that the growth of the inland dunes is fed by sand from the beach. All the volumetric changes occurred due to sand redistribution within the system, with erosion along the beach, and deposition and erosion in the dune areas.

Unlocking Production Potential through Sand Management What–If Analysis in Digital Fields

Sand production associated with oil and gas producers is one of the oldest problems in the industry and is typically in unconsolidated sandstone formations. The stresses caused by the fluids flowing into the wellbore are often sufficient to produce fine sand particles. Sand production may cause operational problems such as disposal of produced sand, sand erosion of downhole and surface equipment, and loss of primary containment (LOPC), which is the most important reason for controlling sand production. In actual field operation, a sand management program is usually implemented to manage sand challenges which limits to monitoring and basic analysis. The proposed sand management solution in this paper performs sensitivity analysis (known as what–if scenarios) using model–based sand erosion calculation to analyze different possible operating scenarios with the objective of preventing and minimizing sand issues. The solution also helps to minimize risks related to well, facilities and avoiding cost or production losses due to sand production. It recommends the operational settings to achieve maximum production rates while ensuring operating within safe erosion limits and without sand deposition risk.

Improved Prediction of Sand Erosion by Accurate Particle Shape Representation in CFD-DEM Modelling

Predicting accurate erosion rate due to sand particles in oil and gas production is important for maintaining safe and reliable operations while maximizing output efficiency. Computational Fluid Dynamic (CFD) is a powerful tool for erosion prediction as it provides detailed erosion pattern in complex geometry. In an effort to improve accuracy of erosion prediction, this paper proposes an algorithm to accurately represent particle shape in CFD erosion simulation through coupling with Discrete Element Method (DEM) for non-spherical shape particles. The fluid motions are predicted by CFD and the particle movements (including particle-particle and particle-wall collisions) and fluid-particle interaction are calculated using DEM. It is widely known that sand particles are of finite volume with a non-spherical shape, accurate representation of sand particles is important in CFD modelling for accurate prediction of erosion rate. Traditional CFD approach usages lagrangian tracking of sand particles through Discrete Phase Model (DPM), where a particle is assumed as a point mass for the calculation of trajectory and particle-wall interaction. Particle impact velocity and impact angle are important parameter in determining erosion. Assumption of point mass in DPM approach, will not capture particle-wall interaction accurately especially when particles are of non-spherical in shape. In additional, DPM approach ignores particle-particle interactions. This can adversary affect the accuracy of erosion predictions. Integrating non-spherical DEM collision algorithm with CFD erosion simulation, will overcome these limitations and improve erosion predictions. Benefits of this CFD-DEM erosion modelling was demonstrated for gas-solid flow in a 2" pipework which consists of out-of-plane elbows in series and blind-tees. Experimental dataset [1] for erosion pattern on each elbow was used to validate CFD predictions. Three different erosion CFD simulations were performed, traditional DPM based CFD simulation, CFD-DEM simulation for spherical shape particles and CFD-DEM simulation for non-spherical shape particles. CFD-DEM coupled simulations clearly show an improvement on erosion predictions compared to DPM based CFD simulation. Effect of non-spherical shape on rebound angle during particle-wall collision is captured accurately in CFD-DEM simulation. CFD-DEM simulation using non-spherical particle, was able to predict erosion pattern closer to experimental observations. This paper will demonstrate an increase in accuracy of sand erosion prediction by integrating DEM collision algorithm in CFD modelling. The prediction results of elbow erosion subject to a condition of dilute gas-particle flow are validated against experimental data. Improved prediction of erosion risk will increase the safety and reliability of oil & gas operations, while maximizing output efficiency.

Numerical Analysis of Elbow Erosion Mitigation Using Swirl Pipes in Gas-Particle Two-Phase Flows

In the oil and gas industry, sand particle erosion damage to elbows is a common problem. The ability to predict erosion patterns is of great importance for sizing lines, analyzing failures, and limiting production rates. Computational fluid dynamics (CFD) can be utilized to study the erosion behavior and mitigate the erosion problem for safety purposes and greater equipment longevity. In order to alleviate the adverse results of sand erosion in elbows, the current study investigated the potential of the geometrically induced swirl flow generated from flow passing through a four-lobed twisted pipe upstream of an elbow. To this end, first, the airflow in a standard elbow equipped with different swirl pipes was simulated using the SIMPLE method, then an Eulerian-Lagrangian approach was employed to track the particles, and finally, the erosion rate was computed. The simulation results indicated that the elbow’s maximum erosion rate with twisted pipes placed upstream of the elbow is lower than the one obtained for the standard pipe. In addition, as the twisted pipe position gets closer to the bend, the erosion rate further reduces. Thus, swirling flows provide a promising prospect as a mechanism to control the erosion rate in elbows.

Unlocking Potential Thru Sand Management Insights in Digital Fields

Sand production is creating sand erosion and deposition issues at multiples levels such as tubing, choke and pipeline, therefore causing multiples undesirable events such as unplanned production deferment, integrity and sand handling capacity issues in each field. Traditionally, each field has common practices to address sand issues. However, this creates non-standard procedures and prevents sharing best practices around all the assets. Managing sand production and related risks are keys where a multi-disciplined team (from subsurface to the surface) is required to ensure safe operations in more than 45 offshore fields. To efficiently manage such a challenge at scale, there was a need to develop a single common digital platform for all. The digital platform provides unified user experience and proactive actionable insights to all assets with characteristics such as; Scalable to all fields Solution architecture to allow fast implementation Same company-wide user interface/user experience platform To achieve this ambition, it was necessary to move away from traditional waterfall project development to agile approach, automating ingestion of data from multiple sources, integrating the in-house development tool as engine based on equations develop specifically for Malaysia fields. The solution was deployed to all fields during 2019. This had created additional benefits such as Transparency on the data: Anyone can access to any field Visible Metrics: All fields sharing the same metrics, also improving and developing adjustments according to each situation Regulatory Compliance: Helping to keep up to date with sand sampling There are already fields reporting examples of value realization in the form of Cost Avoidance and/or reduction in unplanned deferment due to improved Sand Management handling from the solution. It is expected that the value realization will increase by taking actions of protecting the field of any Loss of Primary Containment (LOPC), saving time of deciding as Process Cycle Efficiency (PCE). The solution can potentially be utilized for annual field forecasting for work program and budget cycle.

Specifications and types of seawall structures needed to protect beaches from sand erosion and storm disasters

When someone decides to buy a house or any other estate near the shoreline, they do not think that in future nature will impact the value of their asset significantly. Further to the risks of hurricanes or any other natural hazards (such as tsunami), waves are gradually shifting the coastlines by displacing soil from a location to various areas. In recent decades, coasts have been affected by a significant deterioration due to weather conditions, waves, and coastal soil erosion. Hence, it needs precise environmental consideration, and preserves coasts for leisure, specifying reasons that promoted effective technologies from immersed structures to coastal nourishing. Therefore, by constructing sea-walls should prevent shoreline environments, especially the mechanism of sedimentation, long-shore transfer of sand, altering the coasts to the significant proportion which results from weathering and sea waves sever. In this paper, an overview submitted to the kinds of seawalls and specifications needed to sustain the seawalls. There explained the positive and negative effects of seawalls on coastal area, and the required factors to enhance seawalls stabilization against overturning and sliding failure. Also, the developed types of seawall structures have been identified that, in addition to the more practical vertical model, the stepped, rubble-mound, and curves have also been designed. It is recommended to coastal structure designer and engineers, in the pre-construction stage should precisely be studied on the coast situation and weathering conditions in the area, that is essential to make sustainable decisions and designs for construction of these structures.