Att använda stora mängder skärvätskor vid en bearbetningsprocess har potentiellt negativ inverkan inte bara för operatören men också på miljön. Utöver detta tillkommer ökade kostnader för tillverkningsprocessen. För att minska skärvätskekonsumtionen under maskinbearbetning införs en teknik som kallas minimalsmörjning(MQL=Minimum Quantity Lubrication) som använder mycket mindre mängd skärvätska men ändå är effektivare än standard kylspolning med skärvätska. Denna avhandling fokuserar på att bestämma konvektionen över ett skär med en konstant värmekälla placerad inuti ett kvadratiskt hölje och beräkningsdomänen för den CFD-modell som presenteras, vilken består av flytande och fasta domäner och interaktion mellan dessa. Möjligheten att använda MQL då lågtemperatur- och högtryckskylmedel appliceras undersöks och hur temperaturen sjunker efter applicering av kylmedel/kylvätskor observeras genom att simulera förhållandena i ANSYS flytande arbetsbänk. Denna tekniks effektivitet bestäms med avseende på huruvida högtrycks- och lågtemperaturkylvätska kan avleda värme och transportera bort spånor från ingreppszonen. Slutligen sammanställs resultaten och därpå dragna slutsatserna. / Employing huge amount of cutting fluids in machining process has potential negative impacts not only to the operator but also to the environment along with increased cost of manufacturing process. To reduce the cutting fluid consumption during machining, a technique called Minimum Quantity Lubrication (MQL) is introduced which uses very less amount of cutting fluid yet being effective than flood cooling. This thesis focuses on determining the convection over a cutting insert with a constant heat source inside a square enclosure and the computational domain of the CFD model presented consists of fluid and solid domains with fluid-solid interaction. The feasibility of MQL using low temperature and high-pressure coolant and observing how temperature is dropping after the application of coolant/coolants by simulating the conditions in ANSYS fluent workbench. The effectiveness of this technique is determined in terms of whether high pressure and low temperature coolant can dissipate heat and remove chips from the cutting interface. Finally drawing conclusion based on results.

At Amgen, the Automated Vision Inspection (AVI) systems capture the movement of unwanted particles in Amgen's drug product containers. For quality inspection, the AVI system must detect these undesired particles using a high speed spin-stop agitation process. To better understand the fluid movements to swirl the particles away from the walls, Computational Fluid Dynamics (CFD) is used to analyze the nature of the two phase flow of air and a liquid solution. Several 2-D and 3-D models were developed using Fluent to create simulations of Amgen's drug product containers for a 1 mL syringe, 2.25 mL syringe, and a 5 mL cartridge. Fluid motion and potential bubble formations were studied within the liquid/gas domain inside the container by varying parameters such as viscosity, angular velocity, and surface tension. Experiments were conducted using Amgen's own equipment to capture the images of the spin-stop process and validate the models created in Fluent. Observations were made to see the effects of bubble formation or splashing during spin-down to rest. The numerical and experimental results showed favorable comparison when measuring the meniscus height or the surface profile between the air and liquid. Also, at high angular velocity and dynamic viscosity, the container experiences instabilities and bubble formations. These studies indicate that CFD can be used as an useful and important tool to study fluid movement during agitation and observe any undesirable results for quality inspection.

<p dir="ltr">Approximately 95% of global steel production relies on continuous casting, there is a need for a practical, cost-effective, and accurate method to guide real-world production. A successful integration of three individual CFD models – spray cooling model, solidification model, and carbon segregation model – was accomplished. To understand the heat transfer behavior on a heated surface, a three-dimensional model was used to simulate the interaction of liquid droplets with a heated surface during the secondary cooling process, employing air-mist nozzles. The real nozzle layout, as employed in a full-scale continuous caster to provide HTC data on slab surface. For solidification model, enthalpy-porosity methods were applied to estimate the metallurgical length and surface temperatures. Carbon transport within the continuous caster was considered, revealing a phenomenon of positive segregation at the center of the slab. Building upon this foundation, further investigations were carried out to assess the implications of nozzle clogging. These effects encompass surface temperature, metallurgical length, and carbon concentration. Commercial software ANSYS Fluent 2021 R2 and Simcenter STAR-CCM+ 2302 are chosen for their exceptional computational performance. MATLAB and Python play key roles in both pre and post processing, including mapping HTC profiles, visualizing shell growth, and extracting temperature and cooling profiles.</p>

Numerical methods for solving partial differential equations are commonplace in the engineering community and their popularity can be attributed to the rapid performance improvement of modern workstations and desktop computers. The ubiquity of computer technology has allowed all areas of engineering to have access to detailed thermal, stress, and fluid flow analysis packages capable of performing complex studies of current and future designs. The rapid pace of computer development, however, has begun to outstrip efforts to reduce analysis overhead. As such, most commercially available software packages are now limited by the human effort required to prepare, develop, and initialize the necessary computational models. Primarily due to the mesh-based analysis methods utilized in these software packages, the dependence on model preparation greatly limits the accessibility of these analysis tools. In response, the so-called meshless or mesh-free methods have seen considerable interest as they promise to greatly reduce the necessary human interaction during model setup. However, despite the success of these methods in areas demanding high degrees of model adaptability (such as crack growth, multi-phase flow, and solid friction), meshless methods have yet to gain notoriety as a viable alternative to more traditional solution approaches in general solution domains. Although this may be due (at least in part) to the relative youth of the techniques, another potential cause is the lack of focus on developing robust methodologies. The failure to approach development from a practical perspective has prevented researchers from obtaining commercially relevant meshless methodologies which reach the full potential of the approach. The primary goal of this research is to present a novel meshless approach called MIMS (Model Integrated Meshless Solver) which establishes the method as a generalized solution technique capable of competing with more traditional PDE methodologies (such as the finite element and finite volume methods). This was accomplished by developing a robust meshless technique as well as a comprehensive model generation procedure. By closely integrating the model generation process into the overall solution methodology, the presented techniques are able to fully exploit the strengths of the meshless approach to achieve levels of automation, stability, and accuracy currently unseen in the area of engineering analysis. Specifically, MIMS implements a blended meshless solution approach which utilizes a variety of shape functions to obtain a stable and accurate iteration process. This solution approach is then integrated with a newly developed, highly adaptive model generation process which employs a quaternary triangular surface discretization for the boundary, a binary-subdivision discretization for the interior, and a unique shadow layer discretization for near-boundary regions. Together, these discretization techniques are able to achieve directionally independent, automatic refinement of the underlying model, allowing the method to generate accurate solutions without need for intermediate human involvement. In addition, by coupling the model generation with the solution process, the presented method is able to address the issue of ill-constructed geometric input (small features, poorly formed faces, etc.) to provide an intuitive, yet powerful approach to solving modern engineering analysis problems.

This project presents the development and implementation of a GPU-accelerated meshless two-phase incompressible fluid flow solver. The solver uses a variant of the Generalized Finite Difference Meshless Method presented by Gerace et al. [1]. The Level Set Method [2] is used for capturing the fluid interface. The Compute Unified Device Architecture (CUDA) language for general-purpose computing on the graphics-processing-unit is used to implement the GPU-accelerated portions of the solver. CUDA allows the programmer to take advantage of the massive parallelism offered by the GPU at a cost that is significantly lower than other parallel computing options. Through the combined use of GPU-acceleration and a radial-basis function (RBF) collocation meshless method, this project seeks to address the issue of speed in computational fluid dynamics. Traditional mesh-based methods require a large amount of user input in the generation and verification of a computational mesh, which is quite time consuming. The RBF meshless method seeks to rectify this issue through the use of a grid of data centers that need not meet stringent geometric requirements like those required by finite-volume and finite-element methods. Further, the use of the GPU to accelerate the method has been shown to provide a 16-fold increase in speed for the solver subroutines that have been accelerated.

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