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There is an urgent need to switch to a low-carbon economy, mostly using renewable energy generation sources, such as wind energy. Due to the intermittent generation nature of these generation methods, there is a need for an energy storage device to level any potential mismatch in generation/demand. The overall areas of interest in this thesis were, firstly what method or approach could be used to compare different electrochemical cell options for a wind-diesel, off grid generation system. Secondly, what are the future challenges with electrochemical cells and what knowledge creation could be carried out to help with this. The first goal of this work was considering the criteria of the selection of a suitable energy storage device. As per the industrial focused requirements of the Engineering Doctorate (EngD), a 'business case' using a commercial renewable energy system software (HOMER) was carried out to compare and contrast different commercial electrochemical cells, in the context of the sponsors wind turbine. It was found that the available commercial Lithium-ion cells were advantageous in terms of the levelised cost of energy output, due to superior performance characteristics. Sodium Ion Batteries (SIB's) offer a potential cheaper, safer and more sustainable alternative to the current dominate technology in the energy storage market, the lithium-Ion batteries (LIB's). Furthermore, the development of all solid-state batteries, in which the currently utilised liquid electrolytes are substituted for solid electrolyte materials, could lead to safer battery systems. Designing suitable solid electrolytes remains a huge scientific challenge, to achieve the desirable electrochemical stability, ion conduction and negligible electronic conduction. The sodium ion conducting Na3Zr2Si2PO12 solid electrolyte, is a promising solid electrolyte material, and is a prolifically studied material in scientific journal publications. A facile solid-state synthesis method was selected, with a novel concept of utilising nano-scale precursor particles to achieve high density, high purity, high conductivity Na3Zr2Si2PO12 pellets. The investigation was carried out with a direct comparison of nano-scale precursors to macro-scale precursors to have a direct comparison of the effect this has on material microstructure and electrochemical performance. The analysis included the use of scanning electron microscope (SEM) images, Brunauer-Emmett-Teller (BET) surface area and porosity measurements, to measure the material characteristics of the pre-sintered powders. For analysis of the synthesised Na3Zr2Si2PO12 pellets, X-ray diffraction (XRD) profiles and Rietveld refinement was used to characterise the phase formation composition and impurity species and content. SEM was used to characterise the crystal microstructure and grain/grain boundary details. Archimedes density testing was used to test the densification of the sintered pellets. To determine the ionic conductivity of the pellets electrochemical impedance spectroscopy (EIS) was used. To test the reliability of the developed sodium ion conducting electrolyte in an electrochemical cell, electrochemical studies were then carried out. Firstly, the interfacial resistances and efficacy to strip/plate sodium metal of the developed Na3Zr2Si2PO12 material was assessed. This was assessed by galvanostatically cycling a Na-metal/ Na3Zr2Si2PO12/Na-metal symmetrical cell. Then the interfacial resistance of the Na-metal/ Na3Zr2Si2PO12 interaction was assessed using an EIS measurement. The developed material pellets showed a promising performance, achieving a competitive ionic conductivity of 1.13 × 10-3 S.cm-1 for nano precursors using the highest sintering duration of 40 hours (at 1230°C). The next step was to develop a solid-state sodium ion cell, this was done with the use of a novel concept of using a reduced graphene oxide (rGO), organic cathode material in a solid-state cell. The use of a carbonaceous cathode material may provide advantages in terms of a 'green' material, when compared to traditional cathode materials. In the study a solid-state cell using a rGO cathode material, a sodium metal anode material and a Na3Zr2Si2PO12 solid electrolyte was developed. The performance of this cell was directly compared to an identical cell, except the use of a more conventional liquid electrolyte (1M NaClO4 in EC: PC). The solid state cell showed very promising results.

One of the main goals of this project was to cultivate an understanding of fluidic nozzle geometries and characteristic flow. Through this knowledge, three new fluidic nozzle concepts were developed to be used as components in several windscreen washer systems for an automotive part supplier, Kautex Textron CVS Ltd. Accurate and conclusive visualisation of flow through fluidic nozzles was vital in understanding how they can be best utilised for different applications. Over the past century, the specific needs of automotive cleaning systems have greatly developed with new technological discoveries, these advances allow the driver further knowledge of their surroundings. These specialised systems each require a different type of maintenance and cleaning system depending on their usage and the different size and shape of the vehicle. By completing this project, it is hoped to allow manufacturers to accurately identify what sort of fluidic nozzles are best for windscreen cleaning systems for a vehicle and how to design a nozzle to suit their specification. Fluidic nozzles have been researched experimentally and computationally to ensure an accurate comparison of results. By guaranteeing a precise comparison it will negate the need for high volume testing of nozzles in experimental situations, greatly reducing time and resources required to analyse a fluidic nozzle. The fluidic nozzles that are investigated and developed in this project were modelled and examined both experimentally and computationally, this ensured valid and accurate results were achieved by both the computational modelling and experimental testing. The development of the nozzles within this project was conducted using several experimental and computational setups to analyse the spray distribution, angle and oscillatory frequency amongst other parameters significant to the nozzle usage on a vehicle. Through this it was possible to tailor nozzle dimensions to allow for a streamlined design approach, this increased efficiency in fluidic nozzle development for any specification given by a vehicle manufacturing company customer. In addition to this the water flow emitted from the outlet was experimentally tested and modelled with both stationary and high surrounding velocities to examine how external variables affect the flow of the water from the nozzle.iiiThis project has been useful in the design manufacturing process of fluidic nozzles, by utilising computational modelling it has allowed a faster and cheaper method of analysing the effect of design alterations to fluidic nozzles. There is a greatly reduced frequency required for rapid prototyping of an array of fluidic chips with minimal dimensional differences to be used in the experimental stages of design, as once the inlet boundary conditions are established the nozzle can be redesigned completely within reason without the need for additional material wastage. This ensures a more easy and precise method of testing the manufacturing tolerances of a fluidic nozzle with a target of reaching customer specifications are always achieved. Three nozzles were aimed developed to satisfy conditions set by the customers, the vehicle manufacturers at which the new nozzle designs are aimed at are Honda, Nissan and Toyota. The nozzles to be established were designed for use on windscreen washer systems with a varying number of nozzles and with diverse windscreen sizes for different vehicles, resulting in a wide variety of specifications that must be met for each vehicle manufacturer. This meant that a single nozzle could not be utilised for all vehicles, instead a base model of fluidic chip was developed for the Nissan vehicle which was then dimensionally changed to suit the other vehicles. Throughout this project there were design specifications changes and ambiguities from the automotive company customers, leading to redesigns of the fluidic chips designed in this project. This means that although only two of the three fluidic nozzle designs are successfully in production, a much greater understanding of the mechanics of the fluid flow within the fluidic nozzle was achieved.

The main aim of this research project is to investigate techniques to improve the resolution of flow variables on unstructured skewed meshes whilst working within a Finite Volume (FV) context. A three-dimensional vertex-based FV algorithm for the solution of thermo- fluid flow problems has been developed and integrated within a multi-physics FV framework PHYSICA. Currently PHYSICA employs a cell-centred discretisation technique for fluid mechanics problems and a vertex-based discretisation technique for solid mechanics problems. The vertex-based discretisation approach is validated for a variety of heat transfer problems and comparisons are made with cell-centred solutions. A coupled thermo-mechanical problem, including solidification and radiation, is simulated using vertex-based and cell-centred techniques. Results, run-time and memory requirements are compared. Hybrid vertex-based/cell-centred discretisation of the hydrodynamic variables is also investigated. The components of velocity are solved vertex-based with pressure cell-centred or conversely pressure is solved vertex-based with velocity cell-centred. The methods are applied to flow in a lid-driven cavity and solutions are obtained on a number of distorted meshes. Comparisons are made with the benchmark solutions. The hybrid discretisation enables solutions on distorted meshes where purely cell-centred techniques fail. The hybrid methods produce final solutions containing errors due to mesh distortion. The co-located vertex-based flow solutions obtained on the distorted meshes are comparable to solutions obtained on a uniform Cartesian mesh. Having a good resolution of the flow field on distorted meshes enables the solution of other transported variables using cell-centred techniques. Finally, this hybrid vertex-based/cell-centred technique is applied to thermally driven flow, turbulent flow, and three-dimensional flow over an aircraft wing.