Rapid depletion of energy resources has immensely affected the transportation sector, where the cargo transportation prices are rising considerably each year. Efforts have been made to develop newer modes of cargo transportation worldwide that are both economical and efficient for a long time. One such mode is the use of energy contained within fluids that flows in the pipelines for transportation of bulk solids. After appropriate modifications to these pipelines, bulk solids can be transported from one location to another very effectively. Solid material can be stored in cylindrical containers (commonly known as capsules), which can then be transported, either singly or in a train through the pipeline. Both the local flow characteristics and global performance parameters associated with such pipelines need careful investigation for economical and efficient system design. Published literature is severely limited in establishing the effects local flow features on system characteristics of Hydraulic Capsule Pipelines (HCPs). The present study focuses on using a well validated Computational Fluid Dynamics (CFD) tool to numerically simulate the solid-liquid mixture flow in HCPs, installed both onshore and offshore , along-with the pipe bends. Local static pressure fields have been discussed in detail for a wide range of geometrical and flow related parameters associated with the capsules and the pipelines. Numerical predictions have been used to develop novel semi-empirical prediction models for pressure drop in HCPs, which have then been embedded into a pipeline optimisation methodology that is based on Least-Cost Principle. This novel optimisation methodology that has been developed for HCPs is both robust and user-friendly.

10 Multistage severe service control valves are extensively used in various energy systems, such 11 as oil & gas, nuclear etc. The primary purpose of such valves is to control the amount of fluid 12 flow passing through them under extreme pressure changes. As opposed to the conventional 13 valves (butterfly, gate etc.), control valves are often installed in energy systems with 14 geometrically complex trims, comprising of various geometrical features, formed by a 15 complex arrangement of cylindrical arrays. The pressure within the trim varies in controlled 16 steps and hence, cavitation resistance can be embedded in the trim through improved design 17 process for the trim for severe service applications in energy systems. The flow 18 characteristics within a control valve are quite complex, owing to complex geometrical 19 features inherent in such designs, which makes it extremely difficult to isolate and quantify 20 contribution of these features on the flow characteristics. One of the most important design 21 parameters of such trims is the flow coefficient (also known as flow capacity) of the trim 22 which depends on the geometrical features of the trim. The design of valves for particular 23 performance envelop within the energy systems depends on effects of complex trim 24 geometrical features on performance characteristics; hence, the focus of recent research is on 25 quantifying the hydrodynamic behaviour of severe service control valves, including the trims. 26 This includes the estimation of the local flow capacity contributions of the geometrical 27 features of the trim through detailed numerical investigations. In this work, a tool has been 28 developed that can be used to predict the local contribution of geometrical features on the 29 flow coefficient of the trim. It is expected that this work will result in better performance of 30 the energy systems where these valves are used. 31 32 Capacity, Energy Systems 34 35 1.0 Introduction 36 Valves are an integral part of any piping network and are used in a variety of industries for 37 various process control applications. The design of valves is a specialist area and the 38 performance of valves is integral to the performance of the energy systems. The severe 39 service control vales typically have very complex flow paths and it is necessary to have 40 understanding of flow characteristics through the complex pathways to eliminate undesirable 41 effects such as vibrations, noise and cavitation in energy systems. The designs of such valves 42 are carried out with the help of well-known standards but many times undesirable local flow 43 effects cannot be eliminated through such designs. The standards are continuously updated to 44 incorporate state of the art knowledge into the design process through extensive experimental 45 and numerical research work carried out all over the world. Newer designs are continuously 46 * Corresponding Author Tel.: +44 1484 472323 1 only partially applicable. In such cases a thorough fluid dynamic analysis is necessary to 2...

The scarcity of fossil fuels is affecting the efficiency of established modes of cargo transport within the transportation industry. Efforts have been made to develop innovative modes of transport that can be adopted for economic and environmental friendly operating systems. Solid material, for instance, can be packed in rectangular containers (commonly known as capsules), which can then be transported in different concentrations very effectively using the fluid energy in pipelines. For economical and efficient design of such systems, both the local flow characteristics and the global performance parameters need to be carefully investigated. Published literature is severely limited in establishing the effects of local flow features on system characteristics of Hydraulic Capsule Pipelines (HCPs). The present study focuses on using a well validated Computational Fluid Dynamics (CFD) tool to numerically simulate the solid-liquid mixture flow in both on-shore and off-shore HCPs applications including bends. Discrete Phase Modelling (DPM) has been employed to calculate the velocity of the rectangular capsules. Numerical predictions have been used to develop novel semi-empirical prediction models for pressure drop in HCPs, which have then been embedded into a robust and user-friendly pipeline optimisation methodology based on Least-Cost Principle.

For safety-critical industrial applications, severe-service valves are often used, and the conditions during operations can be either single phase or multiphase. The design requirements for valves handling multiphase flows can be very different to the single-phase flow and depend on the flow regime within valves. The variation in flow conditions during the operation of such valves can have a significant effect on performance, particularly in oil and gas applications where multiphase behaviour can rapidly change within the valve causing unwanted flow conditions. Current practices in designing and sizing such valves are based solely on global phase properties such as pressure drop of the bulk fluid across the valve and overall phase ratio. These do not take into account local flow conditions, as with multiphase fluids, the flow behaviour across the valve becomes more complex. In this work, wellvalidated computational fluid dynamics (CFD) tools were used to locally and globally quantify the performance characteristics of a severe service valve handling multiphase gas and liquid flow. Such flows are frequently encountered in process equipment found in vital energy industries e.g. process and oil & gas. The CFD model was globally validated with benchmark experiments. Two valve opening positions of 60% and 100% were considered each with 5, 10, and 15% inlet air volume fractions to simulate real life conditions. The results show that while the non-uniformity in pressure field is along expected lines, there is severe non-uniformity in the local air, water and void fraction distributions within the valve trim. To quantify the phase non-uniformities observed, an equation for the distribution parameter was defined and used to calculate its value in each localised quarter within the trim. Phase velocity and void fraction data extracted from the CFD results were also used to obtain relationships for the local void fraction distribution and flow coefficient. The detailed investigation that has been carried out allows for local flow characteristics to be determined and embedded in sizing methodology for severe-service control valve systems with multiphase gas and liquid flow.

Abstract.A capsule pipeline transports material or cargo in capsules propelled by fluid flowing through a pipeline. The cargo may either be contained in capsules (such as wheat enclosed inside sealed cylindrical containers), or may itself be the capsules (such as coal compressed into the shape of a cylinder or sphere). As the concept of capsule transportation is relatively new, the capsule pipelines need to be designed optimally for commercial viability. An optimal design of such a pipeline would have minimum pressure drop due to the presence of the solid medium in the pipeline, which corresponds to minimum head loss and hence minimum pumping power required to drive the capsules and the transporting fluid. The total cost for the manufacturing and maintenance of such pipelines is yet another important variable that needs to be considered for the widespread commercial acceptance of capsule transporting pipelines. To address this, the optimisation technique presented here is based on the least-cost principle. Pressure drop relationships have been incorporated to calculate the pumping requirements for the system. The maintenance and manufacturing costs have been computed separately to analyse their effects on the optimisation process. A design example has been included to show the usage of the model presented. The results indicate that for a specific throughput, there exists an optimum diameter of the pipeline for which the total cost for the piping system is at its minimum.

Control valves are an integral part of a number of energy systems, such as those used in chemical and nuclear industries. These valves are used to regulate the amount of fluid flow passing through these systems. A key component of a control valve is its trim, which in case of a multi-stage continuous-resistance trim consists of a staggered arrangement of columns.Flow passing through the channels formed between adjacent columns (also called as flow paths), loses a significant amount of its energy and regulates the pressure field. As the geometrical features of these flow paths dictate the flow capacity of the trim, systematic investigations have been carried out to analyse the complex flow behaviour within these flow paths. Well-verified computational fluid dynamics based solver has been used to investigate the effects of the geometrical features of flow paths on the flow capacity of the trim, at various valve opening positions. It has been noticed that reducing the size of flow paths increases the flow capacity of the trim, however, at a critical flow path size, the inherent opening characteristics of a trim have been observed to alter. In order to recover the original opening behaviour of the trim, careful manipulation of the flow paths is required, which has been successfully achieved in the present investigation.

Control valves that are used in severe service applications have trim cages that are geometrically quite complex. Most of these trims are manufactured using traditional manufacturing methods which are expensive and time-consuming. In order to reduce manufacturing costs and shorten the product development cycles, Additive Manufacturing (AM) methods have been gaining popularity over the traditional manufacturing methods. Selective Laser Melting (SLM) is one of the most popular AM techniques. In this paper, the effect of the conventional Electron Discharge Machining (EDM) method and the SLM method on the performance characteristics of a complex multi-stage disc stack trim is investigated. Experimental tests conducted on the SLM trim showed that the flow capacity reduced in comparison to the EDM manufactured trim. Surface profile measurements indicated that the surface roughness of the SLM trim was significantly higher than the EDM trim. In order to evaluate the effect of surface roughness on performance in detail, well validated numerical simulations were conducted to compare the local performance of the valve trims manufactured by the two methods. The simulation results showed that the wall shear stress increases by 1.9 times on the trim manufactured by the SLM method due to the increased roughness.

Due to depleting fossil fuels and a rapid increase in the fuel prices globally, the search for alternative energy sources is becoming more and more significant. One of such energy source is the wind energy which can be harnessed with the use of wind turbines. The fundamental principle of wind turbines is to convert the wind energy into first mechanical and then into electrical form. The relatively simple operation of such turbines has stirred the researchers to come up with innovative designs for global acceptance and to make these turbines commercially viable. Furthermore, the maintenance of wind turbines has long been a topic of interest. Condition based monitoring of wind turbines is essential to maintain continuous operation of wind turbines. The present work focuses on the difference in the outputs of a vertical axis wind turbine (VAWT) under different operational conditions. A Computational Fluid Dynamics (CFD) technique has been used for various blade configurations of a VAWT. The results indicate that there is significant degradation in the performance output of wind turbines as the number of blades broken or missing from the VAWT increases. The study predicts the faults in the blades of VAWTs by monitoring its output.