CFD applications in offshore engineering

A Scalable Infrastructure for Online Performance Analysis on CFD Application

In this review, the application of computational fluid dynamics (CFD) simulations in analyzing thermal processes within food technology is explored. The focus is on understanding heat transfer, fluid flow, and temperature distribution during various food processing methods, such as baking, frying, pasteurization, and cooling. Detailed insights that are often challenging to obtain through experimental methods alone are provided by CFD simulations, allowing for the optimization of process parameters to enhance product quality and safety. It is demonstrated that CFD can effectively model complex thermal phenomena, providing valuable data on temperature gradients and flow patterns. These simulations assist in the designing of more efficient processing equipment, improving energy consumption, and ensuring uniform heat treatment, which is crucial for maintaining the nutritional and sensory attributes of food products. Furthermore, the integration of CFD in the food industry leads to significant advancements in product development, reducing the time and cost associated with experimental trials. Future research should focus on refining these models for greater accuracy and exploring their application in emerging food processing technologies.

Computational fluid dynamics (CFD) techniques have become an important tool for investigating and predicting flow behavior in many industrial and engineering processes. In the last two decades, CFD has been used for the study, design, and improvement of irrigation equipment. Numerical simulations can be used to predict fluid flow, heat transfer, and chemical reactions within complex systems. The objective of this review is to provide an overview of the uses of CFD in irrigation engineering applications. The paper is organized into two main sections: fundamentals of CFD and irrigation engineering applications. The first section presents the main methods used in numerical simulations, basic equations to predict fluid flow parameters, meshing concerns, and convergence criteria. In the second section, we present applications related to friction and local head losses in pipes, liquid and solid-liquid flow simulation in drippers, chemical scaling, filters, sprinklers, direct-acting pressure-regulating valves, and Venturi injectors. The briefly described applications indicated that CFD modeling can be an accurate, quick, and feasible method for the investigation of flow parameters in irrigation pipes, fittings, emitters, and accessories. The CFD simulations can be useful for designing new products as well as for improving and optimizing existing products. Computational fluid dynamics uses in irrigation engineering must be encouraged, particularly for innovation purposes resulting from the cooperation between academia and irrigation companies.

Establishing accurate hydrodynamic models for underwater vehicles requires extensive motion and force data. However, acquiring such data through full-scale sea trials involves complex platforms, sensors, and control technologies, presenting significant constraints and substantial costs. Therefore, identifying reliable alternative approaches, such as Computational Fluid Dynamics (CFD) simulations, is essential for efficiently obtaining the requisite modeling data. This study employs CFD techniques to conduct simulations, specifically utilizing the overset mesh method to address the multi-degree-of-freedom motion of the vehicle. Concurrently, Circulating Water Channel (CWC) experiments were performed to obtain comparative data. The simulation results demonstrate strong agreement with the experimental measurements, validating the accuracy and reliability of CFD simulations in predicting the hydrodynamic characteristics of underwater vehicles. The findings indicate that the adopted CFD simulation methodology can provide a credible data foundation for hydrodynamic modeling of underwater vehicles, effectively overcoming the numerous limitations associated with sea trials.

Perforate-Wash-Cement (P/W/C) is a well plugging technique extensively used by ConocoPhillips in the Greater Ekofisk Area over the last ten years. In Jet-type P/W/C, Tubing Conveyed Perforating (TCP) guns perforate casing in the target interval before the zone is washed and a cross-sectional cement plug is installed using a specialized Bottom Hole Assembly (BHA). The goal is to maximize the cement plug quality through optimizing the BHA and operational process parameters within constraints imposed by the operating conditions. This paper describes application of Computational Fluid Dynamics (CFD) to achieve this objective. CFD is well suited for modeling wash and cement processes including the associated non-Newtonian fluids. A CFD model of these processes employs unsteady multiphase Reynolds Averaged Navier Stokes (RANS) based Volume of Fluid (VOF) approach with a Shear Stress Transport (SST) K-omega turbulence model. BHA translation and rotation are simulated using moving deforming-layering mesh with interface approach. Physical properties of non-Newtonian fluids selected are based on in-situ conditions and derived via lab tests. CFD-specific considerations such as domain size, turbulence model, mesh type and size, and computational timestep are discussed in this paper. The magnitude and duration of the jet-induced "pressure pulse" in the annular space between the formation wall and the casing are a key to efficient displacement during the wash and cementing processes. Displacement efficiency, in terms of the percentage of mud or cement in a control volume as a function of time, depends on perforation size and density, nozzle size/number, flow rate, fluid properties, as the ROP/BHA pulling speed and tool RPM. Key findings from a parametric study to optimize these parameters are presented. To validate CFD nozzle flow predictions and to rule out potential for false results due to cavitation, laboratory tests were performed under pressurized conditions. A comparison of results from CFD simulations using traditional versus optimized parameters are presented, demonstrating significant efficiency improvement achieved. The study initially focused on North Sea application. Encouraged by substantial improvement in process efficiency through parametric optimization, the technique was extended to UK operations and is planned for the Bayu-Undan field. Cementing simulation results for Bayu-Undan specific well configurations are presented, showing how CFD modeling helped reveal less than ideal cementing efficiency. Ultimately, this work provides significant time savings and quality improvement for P&A projects while maintaining a high safety standard.

The computational fluid dynamics (CFD) grid application platform provides a grid environment for CFD applications using high performance computing. It adopts service oriented architecture (SOA), is based on IBM's Service Domain, extends and customizes it for CFD applications in several modules, such as service requesting, job scheduling, job management, failure recovery, etc. By defining general CFD application interfaces such as data format, the platform integrates different CFD applications, including mesh generation, domain decomposition and resolvers, to follow the workflow customized by end-users to finish a complete CFD job. Furthermore, CFD application development specifications and packages are provided to facilitate migrating most sequential and parallel CFD applications to the platform. Currently, a prototype system is available online to the public for testing.

This paper presents an application of Computational Fluid Dynamics (CFD) technique for designing of protective fences for shelter from snow and winds commonly used on offshore rigs and other facilities in cold regions. The CFD simulation of real situations provided detailed information about the flow characteristics behind the fence and the effective shelter zone. Such flow details are usually very expensive, time consuming and difficult to obtain by physical experiments. The numerical simulations found that the shape of pores and surface shear stress has significant impact on the reattachment length and the size of effective fence zone. The effective shelter distance can be increased by avoiding sharp angular corners in the porous pores and reducing surface shear stress. The 3D modelling and CFD simulation provide detailed aerodynamics flow characteristics and stress distributions that allow evaluating a number of designs cost effectively. The technique can be integrated with small-scale intelligent manufacturing system (SIMS) for flexible design and manufacturing of fences.

The application of computational fluid dynamics(CFD) in the food industry such as drying, thermal sterilization, mixing, refrigeration and humidification of cold storage was reviewed. The results from previous studies have shown that CFD was a powerful numerical tool that is applied to model fluid flow situations and aid in the optimal design of engineering equipment and food process. With the development of computer technology, it is conceivable that CFD will continue to provide more explanations for physical modeling of fluid flow and process system design for the food industry.

Preconditioned Krylov subspace methods for solving nonsymmetric matrices from CFD applications

<div class="htmlview paragraph">Development of Caterpillar Fuel Systems' MEUI-B injector has involved application of Computational Fluid Dynamics (CFD) in order to improve performance of the high pressure spill valve. Initial performance bench testing with concept stage experimental injectors indicated that the chamber pressure was decaying at an unacceptably slow rate, and the valve demonstrated erratic behavior at some operating conditions. The slow pressure decay and inconsistent spill valve motion were believed to be caused by flow forces generated during the low lift portion of the spill valve opening event. This theory was pursued by utilizing CFD to design two valves for testing in the next phase of the injector development cycle: A baseline geometry, similar to the original concept injector valve, and a new design incorporating localized seat geometry changes for inducing flow force assisted valve opening. Bench test performance data clearly shows that the modified design significantly improves the spill valve opening event and subsequent chamber pressure decay rate. This paper documents the CFD analysis which led to the development of the new MEUI-B high pressure spill valve design.</div>

Computational fluid dynamics

Most of us are not familiar with the concept that an internal combustion (IC) engine is working on a four-stroke six-event principle. The six events are suction, compression, combustion, expansion, blow-down and exhaust. However, the expansion and blow-down happen in the power stroke and they can be clubbed together. Therefore, we can say that an engine, whether diesel or gasoline, is working on four-stroke five-event principle. The purpose of this chapter is to make the reader to familiarize with the complexities involved in the working of a four-stroke engine. The five events which are completed in four strokes are: suction, compression, combustion, expansion and exhaust. Application of computational fluid dynamics (CFD) principles for each process mentioned above is a challenging job. The difficulty in understanding the working of an IC engine is due to the fact that we cannot see what is happening inside the cylinder piston arrangement. All that is described in textbooks is based on our knowledge gained over a period of time by conducting experiments. There is no doubt in saying that “seeing is believing”. As it is next to impossible to have a complete experimental flow visualization, nowadays CFD comes in handy to have theoretical flow visualization. Well-developed software is available for the simulation in 3D geometries. In this chapter, we explain step-by-step the details required for the CFD simulation of various processes in an IC engine. Extensive results obtained over a period of 20 years of research by the application of CFD in analysing the flow in engines are comprehensively presented and discussed. CFD can be very well applied for analysing any particular process. It can also be used for the modification of the existing engine design or can also be employed for a new design of an engine. It is hoped that readers may be benefitted in understanding the application of CFD for fluid flow analysis and engine design by reading this chapter. Therefore, the main aim of this chapter is to make the reader appreciate how exactly CFD can be applied for design of an engine. As it is application oriented, we are not going deep into the equations, modelling, etc. A number of case studies are presented and discussed.

In the industrial application of Computational Fluid Dynamics (CFD), the quality of simulations and the level of reliability of the results have emerged as major issues of concern. This paper describes a recent initiative of ERCOFTAC (European Research Community on Flow Turbulence and Combustion), involving European code developers, code vendors, academics and industrial users, to set up a practical set of standard guidelines to improve the quality of CFD simulations and to help in the assessment of the trustworthiness of the CFD results. The initiative led to the publication of the first edition of the ERCOFTAC Best Practice Guidelines (BPG) in January 2000. The BPG provide generic advice on how to perform quality CFD calculations. Some examples of typical guidelines from the BPG are provided in this paper.

The effects of task-ambient (TA) air-conditioning systems on the air-conditioning loads in a subway station and the thermal comfort of passengers were studied using computational fluid dynamics (CFD) and pedestrian-behavior simulations. The pedestrian-behavior model was applied to a standard subway station. Task areas were set up to match with crowdedness as predicted by the pedestrian-behavior simulations. Subsequently, a variety of TA air-conditioning systems were designed to selectively control the microclimate of the task areas. Their effects on the thermal environment in the station in winter were predicted by CFD. The results were compared with those of a conventional air-conditioning system and evaluated in relation to the thermal comfort of subway users and the air-conditioning loads. The comparison showed that TA air-conditioning systems improved thermal comfort and decreased air-conditioning loads.

For more efficient design of a horizontal-flow baffled-channel powdered activated carbon (PAC) contactor (hBPC), which might be used to cope with taste and odor problems at conventional water treatment plants, computational fluid dynamics (CFD) using FLOW-3D was applied. In order to verify the performance of the CFD simulations, the experimental results of tracer tests from a pilot-scale hBPC were compared to those from the simulation. Results from the CFD simulation were very similar to those of the tracer tests. Velocity distributions showed that there were stagnant regions on the back side of the baffles. These stagnant regions would be expected to decrease the overall adsorption efficiency of the PAC particles. The size of the stagnant regions and retention times in the simulated hBPC increased as the length to width (L/W) ratio increased and the bend width decreased. The L/W ratio, bend width, and the number of baffles for optimal design of the hBPC were successfully generated by the simulation. When designing a full-scale hBPC, the designer should consider the L/W ratio, number of baffles, and bend width in order to maximize the hBPC performance.