As a young child, my father once told me that it is impossible to know and understand everything. At first I did not believe him, but as I grew up, I realised why he said it. This realisation did not, however, dawn on me overnight. During my training many textbooks and lecturers painted the picture of a world that can be described by a few simple laws. When I finished my training and started to work as a water engineer, I realised that this was only an illusion. The difference between theory and practise was bigger than I thought. I eventually came to the realisation, through the wisdom of many others, that this gap between theory and reality is not only due to the limitations of science and technology, but also to beliefs. Often these beliefs are so intertwined with science and technology that the scientists and technologists themselves are not aware of it. This study attempts to explain why differences between theory and practise exist. The modelling of water treatment process tanks is used as a vehicle to demonstrate this. In the process it is shown that scientists and technologists cannot use models in a responsible manner without also considering the broader philosophical aspects. My personal most satisfying contribution was to demonstrate the influence of philosophical views on process tank design methods. The study also makes original contributions in the field of water treatment process tank modelling. Computational Fluid Dynamic models are used in an attempt to understand water treatment process tanks better. This modelling technique applies a combination of scientific, technological and modelling concepts. An appropriate question by many technical readers will be why a significant portion of this text includes philosophical concepts if the title of the study deals with process tank modelling? First the arguments presented and the process of argumentation, can assist many scientists and engineers to develop a much broader view of science, technology and models. A second reason for this inclusion is the background it gives to where theories originated and how they were developed. Most importantly, however, the realisation of the inherent shortcomings of theories came much later and this is the third reason for its inclusion. It deals with exposing invalid assumptions and misconceptions that are held in the design of some process tanks. These misconceptions often originate from a philosophical view rather than a scientific observation. The fourth reason is to demonstrate the importance of normative aspects in the practise of science and technology. Finally, it can also benefit philosophers in the sense that they can see how philosophy can be applied to very practical problems. A need that is unsatisfied in many scientific and technical fields. / Prof. J. Haarhoff

In water conveyance systems, sudden changes in the flow velocity cause a phenomenon called waterhammer associated with high pressure head changes. Unless a control device is used as a precaution, waterhammer may result in costly damages and even in some cases, loss of human lives. In light of this concept, different control devices that can protect the systems against waterhammer are introduced so that the great pressure differences are absorbed and the system is maintained undamaged. In this thesis, the main functions, the requirements for its construction and the different types of the surge tanks are explained. The governing differential equations defining the flow conditions of the surge tanks and their solutions are provided. In addition, for the use of design engineers a procedure to determine proper dimensions of a surge tank is developed. For the sake of dimensioning the surge tank effectively, empirical equations, which calculate the height of three different types of surge tanks with dimensionless parameters, are obtained. With the help of regression analysis, the correlation between the parameters of the developed equations are determined, and found to be relatively high. Finally, the economical aspect of a surge tank is discussed and comparison parameters are introduced to the designer.

<p>Current small satellite propellant tank design is driven by three factors: volume op-timization, manufacturing capability, and propellant management. Conformal propellanttanks offer solutions to the design challenges of optimizing satellite volume and manufac-turing costs. Conformal propellant tank designs that meet these challenges have unknowneffects on propellant management. Compounding this uncertainty is the industry shift to-wards new green propellants with large contact angles. Improper propellant managementcan deliver gas to a thruster or leave propellant trapped away from the tank outlet whiledraining. Both scenarios reduce the lifespan of satellites.</p> <p>Stamping is one manufacturing process that can produce tanks that optimize volumeand are relatively easy to manufacture. The effects of the stamping process on tank shapeand propellant management is evaluated through testing four different tank geometries. Thestamping process sometimes leaves behind a seam where two sides of a tank are joinedtogether. A total of six tank and vane combinations are tested. One set of traditional tanksserve as a control. Three tanks tested share vane geometry and have different interiors toevaluate the effects of the stamping process on propellant management. The first tank hasa smooth interior, the second has a seam at the joints and the third tank has a seam andridges for increased stiffness. The last two tanks have an interior in the shape of an arc andhave different vanes. The experiment is flown on the ZeroG airplane to test the tank andvane designs in a weightless environment.</p> <p>The experiment consists of a payload rack, eleven experimental pods and one powerdistribution pod. Each experimental pod is designed to be modular and independent fromall other experimental pods. Each experimental pod hosts a camera, electrical box, secondcontainment and fluid system with four tanks.</p> <p>The results of this study show no discernible difference could be observed between tankswith or without a seam from the stamping process. When ridges are added to a tank thatare parallel to the contact line, liquid may not wick into the ridge if it is dry. If the ridgeis wet the liquid spreads out on the surface of the tank further. The differences betweenpropellant positioning for zero and nonzero contact angle fluids are discussed</p> <p><br></p>

Hydraulic tanks have a variety of different tasks. The have to store the volume of oil needed for asymmetric actors in the system as well as to supply the system with preconditioned oil. This includes the deaeration as air contamination is affecting the overall system performance. The separation of the air in the tank is being realized mainly by passive methods, improving the guidance of the air and oil flow. The use of CFD models to improve the design of hydraulic tank is recently often discussed. In this paper, a design method for hydraulic tanks using CFD is presented and discussed. First the different requirements on a hydraulic tank are described as well as the motivation changing the tank designs. Additionally, a quick overview on different calculation models for the behavior of air in oil as well as the capabilities of CFD to reproduce them is given. After this the methodology of tank design applying CFD is presented. The method is then used in an example.

The strength of thin-walled cylindrical shell structures is highly dependent on the nature and magnitude of imperfections. Most importantly, circumferential imperfections have been reported to have an especially detrimental effect on the buckling resistance of these shells under axial load. Due to the manufacturing techniques commonly used during the erection of steel silos and tanks, specific types of imperfections are introduced into these structures, among them circumferential weld-induced imperfections between strakes of steel plates. The main objective of this thesis was to investigate the exact nature of these circumferential welds and their influence on the buckling resistance of silos and tanks under axial load. The results of a survey of imperfections in existing silos at a location in Port Kembla / Australia (Ding 1992) were used to develop and calibrate a shape function which accurately describes the geometric features of circumferential weld imperfections. It was found that after filtering out the effects of overall imperfections, three parameters governed the shape of the surveyed imperfections: the depth; the wave length; and the roundness. A study on several factors influencing the buckling of silos and tanks was carried out using the finite element method. The interaction between neighbouring circumferential weld imperfections was investigated and it was found that the influence on the buckling behaviour depended on the strake height in relation to the linear meridional bending half wave length and the depth of the imperfection. The strengthening effect of weld-induced residual stress fields for a range of different geometries was also studied, and diagrams were derived giving the influence of the newly developed shape function on the buckling behaviour. A post-buckling analysis was undertaken and a model for the post-buckling behaviour of cylindrical thin-walled shells with circumferential weld imperfections was developed. The methods used for the analysis of thin-walled cylinders were applied in a study on the buckling behaviour of welded box-sections. It was found that weld-induced residual stress fields governed the buckling behaviour of these columns / Doctor of Philosophy (PhD)

The thesis deals with the analysis of a reinforced concrete digestate tank. The tank is built as a semi-underground construction. The roof is designed as a reinforced concrete dome, which is prestressed in a circular beam with prestressing cables - monostrands. The calculation of internal forces were performed by the software SCIA Engineer. The structure was assessed for the ultimate limit state and the ultimate serviceability state, in terms of watertightness for the width of cracks.

The aim of this diploma thesis is to design of storage tank for petroleum. The thesis is divided into two parts. In the first part of the work is focused on introducing the known types of storage tanks, their parts, use and benefits. The thesis also briefly summarized legislation regarding this issue. The second part is the actual design of storage tank. It was the strength calculation tanks according to EN 14 015. It was also a voltage FEM analysis of shell and tank roof. Result of work is a design drawing of the storage tank.

Hydraulic tanks have a variety of different tasks. The have to store the volume of oil needed for asymmetric actors in the system as well as to supply the system with preconditioned oil. This includes the deaeration as air contamination is affecting the overall system performance. The separation of the air in the tank is being realized mainly by passive methods, improving the guidance of the air and oil flow. The use of CFD models to improve the design of hydraulic tank is recently often discussed. In this paper, a design method for hydraulic tanks using CFD is presented and discussed. First the different requirements on a hydraulic tank are described as well as the motivation changing the tank designs. Additionally, a quick overview on different calculation models for the behavior of air in oil as well as the capabilities of CFD to reproduce them is given. After this the methodology of tank design applying CFD is presented. The method is then used in an example.

In order to enhance accessibility to microgravity research, the design process for experiments on the ISS must be streamlined and accessible to all scientific disciplines, not just aerospace engineers. Thus, a general design and analysis toolbox with accompanying best practices manual for microgravity liquid containment is proposed. The work presented in this thesis improves the design process by introducing a modular liquid tank design which can be filled, drained, or act as a passive liquid-gas separation device. It can also be pressurized, and used for aerosol spray. This tank can be modified to meet the design requirements of various experimental setups and liquids. Furthermore, rough simulations of this tank are presented and available to the user for modification. The simulation and design methodology for other general cases is discussed as well. After reading this thesis, the user should have a basic understanding of how liquids behave in microgravity. She will be able to run simple simulations, design, build, test, and fly a liquid management device which has been modified to suit the requirements of her specific experiment. The general tank design can be manufactured using 3-D printing, traditional CNC milling, or a combination thereof. The design methodology and best practices presented here have been used to design tanks used in experiments on the International Space Station for Budweiser and Lambda Vision. Both tanks functioned nominally on orbit. While the specific data from these experiments cannot be presented due to proprietary restrictions, using this thesis as a design guide for new experiments should yield favorable results when applied to new tank designs. If the reader has any questions or would like an updated design process, the author’s preferred contact information can be found using the Orcid iD: 0000-0002-2617-2957 .