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- PostMicroservice integration testing with hardware-in-the-loop in CI/CD pipelines(2024) Johansson, Axel; Paulsson, Simon; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Chalmers University of Technology / Department of Mechanics and Maritime Sciences; Benderius, Ola; Benderius, OlaMechanical products are increasingly evolving into software-driven systems with expanded responsibilities, as exemplified by the rapid advancements in the vehicle industry and the rise of autonomous driving technologies. Cyber-physical systems (CPSs), such as vehicles that rely on both hardware and software, present significant testing challenges due to their distributed nature and the necessity for real sensor input data. Traditional testing methodologies are suboptimal for CPS, as they typically do not accommodate the integration of both simulation and hardware testing in a distributed environment. This thesis aims to evaluate the feasibility and effectiveness of a containerized, microservice-based testing framework. The framework is designed to support simulation, data replay and hardware test levels and to be integrated into a continuous integration and continuous deployment (CI/CD) pipeline. The proposed framework was implemented and tested within the context of the TME290 Autonomous robots course at Chalmers University of Technology. This involved the development of hardware-in-the-loop (HIL) rigs, as well as the creation of test execution and interpretation software. The framework’s capabilities were assessed through the execution of various test scenarios. The integration of the testing framework into the course demonstrated its suitability for simulation, data replay, and hardware test levels on a distributed system. Furthermore, it was successfully integrated into a CI/CD pipeline. The findings suggest that a microservice-based architecture can effectively be used for the integration testing of CPS within a continuous integration environment. This approach enhances the reliability and efficiency of testing processes for autonomous systems, offering a promising solution to the challenges associated with traditional CPS testing methods.
- PostSimulation and prediction of BEV heat pumps system performance in cold climates(2024) Nandi, Swaroop; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Chalmers University of Technology / Department of Mechanics and Maritime Sciences; Sebben, Simone; Jamshidi, HamedThe rapid evolution of the automotive sector toward electric vehicles is significantly propelled by the technological advancements in thermal management systems. Battery Electric Vehicles (BEVs) show a high sensitivity when it comes to temperature control. This study focuses on one such issue regarding thermal management systems of BEV. At lower temperature and high humidity levels, while using ambient heat for thermal comfort, the radiator while picking up heat acts as a condenser and because of high moister in the air there is a high probability of icing on the heat exchanger surface. This frost formed on the heat exchanger surface will hinder the heat transfer efficiency and thereby the thermal performance. Hence, predicting this frost formation on the heat is indispensable. This frost is a result of different physical parameters and thermodynamic properties that include, relative humidity, ambient temperature, coolant temperature, airflow rate and the interaction happening between these properties. Hence there is a need to understand these relations to predict the frost formation. This master thesis project centers on the prediction and simulation of BEV heat pump system performance in cold climates, particularly focusing on addressing the issue of frosting. Hence, there's a critical need for reliable methodology to simulate and predict its formation under varying conditions, enabling a deeper understanding of the correlation between environmental factors and performance parameters of heat exchanger. The methodology focuses on establishing a numerical correlation between different frost parameters. Developing mathematical models and employing the numerical correlations to accurately predict the onset of frost, sufficing this issue is key in advancing BEV heat pump systems. By closing the gap between theory and practical application, this thesis seeks to contribute to the development of a reliable and efficient BEV heat pump systems. This research also emphasizes on vital aspect of defrosting. Effective defrosting strategies are necessary for preserving vehicle thermal comfort and performance. The research follows a comprehensive approach, starting with a comprehensive literature review of the current state of research in the field. Lastly, the simulations & mathematical models will undergo rigorous experimental verification with an existing experiment on Volvo Cars Corporation radiators and establishes a possible numerical relation between frost parameters. Ultimately, the research aims to enhance the efficiency and reliability of BEV heat pump systems through simulations and analysis, particularly in cold climates, thereby contributing to the ongoing evolution of electric vehicle technology.
- PostA Comparative Study on Alternative Marine Fuels: Economic, Technology, Environmental and Safety Issues(2024) Nasir, Hamza; Tian, Tian; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Chalmers University of Technology / Department of Mechanics and Maritime Sciences; Li, Zhiyuan; Brynolf, Selma; Lindmark, Olle; Li, ZhiyuanTransitioning to sustainable energy sources in the maritime industry is imperative for mitigating environmental impacts and achieving long-term sustainability goals. This master thesis explores the feasibility and potential of hydrogen as an alternative marine fuel, comparing it with other options such as liquefied natural gas, methanol, and ammonia. The study addresses several key questions: What are the technological, economic, environmental, and safety implications of adopting hydrogen as a marine fuel? & How does hydrogen compare to other alternative fuels in terms of these criteria? The authors employ a multidimensional analysis approach, incorporating methodologies such as the Analytical Hierarchy Process (AHP) and a Case Study of MV Venta Maersk to evaluate the performance of alternative fuels. The study begins by examining the technological landscape through a literature review, highlighting the challenges and opportunities associated with hydrogen production, storage, transportation, and utilization. It concludes that Carbon Capture and Storage technology, critical for blue hydrogen production, faces challenges related to stringent requirements and consistent natural gas supply. Conversely, green hydrogen production poses formidable hurdles due to cost implications and necessitates advancements in electrolysis technology and supportive governmental policies. In assessing the environmental impact, this study emphasizes the significance of greenhouse gas emissions and marine pollution. Hydrogen emerges as a promising option, offering zero emissions during combustion and minimal environmental impact. However, the inherent characteristics of hydrogen pose technical and safety challenges. While LNG also demonstrates commendable environmental performance, generating minimal NOx and Particulate Matter emissions during use, it remains the top priority among alternative fuels due to its early adoption and relatively mature infrastructure. The AHP results from surveys have revealed a priority on safety and environmental concerns as critical criteria in the evaluation of alternative fuels. Methanol and ammonia rank lower in the comprehensive assessment due to their inherent challenges and safety considerations. Despite their potential, further research and development efforts are warranted to address technical and safety challenges and harness their full potential as viable fuel options. The study concludes by providing insights on limitations and suggests future research directions, emphasizing the need for technological innovation, supply chain optimization, and policy interventions to facilitate the adoption of alternative fuels.
- PostThermal Management of Electric Vehicle Rapid Charging(2024) Barani, Amirhossein; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Chalmers University of Technology / Department of Mechanics and Maritime Sciences; Vdovin, Alexey; Jahnen, TimOne of the main barriers to rapid charging of electric vehicles is the thermal management of batteries and charging equipment. Current charging patterns are designed to maintain battery health and safety while avoiding thermal events. Additionally, protection systems monitor the temperature of charging components and, if it exceeds safe limits, reduce power intake to mitigate risks. This increases charging time and impacts the reliability of rapid charging systems. An efficient thermal management system plays a key role in increasing charging stability and enabling faster charging at higher capacities. This study investigates the thermal management of charging cables and power modules in a Megawatt Charging System (MCS) suitable for heavy-duty vehicles. The research is divided into two parts. First, 3D CFD simulations are conducted for three liquid-cooled cable structures to compare their performance and determine their energy loss and cooling demand. Based on these results, in the second part, four cooling systems (heatsink, heatsink+PCM, liquid cooling, and immersion coolng) are designed for the power modules, and their performance is studied through 1D simulations. The findings provide a holistic view of the capabilities of various thermal management strategies and determine their efficiency in various scenarios. Considering the oil-cooled charging cable model and the liquid cooling system as the reference, the results demonstrate that charging a heavy-duty EV with a 1 MW MCS under a constant current-constant voltage (CC-CV) charging method for 45 minutes transfers 370 kWh of energy to the battery. The total system efficiency, including power modules and cables, is 97.3%. Of the input energy, 9.12 kWh ( 2.4%) is lost in the power modules, 0.41 kWh ( 0.1%) in the charging cable and its cooling system, and 0.34 kWh ( 0.1%) in the power module cooling system.
- PostScaling Effects for Hydrofoil Testing: Developing a methodology for hydrofoil performance measurements in towing tank(2024) Eriksson, Wilhelm; Varvne, Marcus; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Chalmers University of Technology / Department of Mechanics and Maritime Sciences; Eslamdoost, Arash; Eslamdoost, Arash; Shiri, AlexThe fast development and growing interest in hydrofoils within marine applications have led to an increased demand for testing and verification of foil designs. Testing model scale hydrofoils is not as straightforward as for traditional displacement hull models. Currently, there does not exist a proposed way of scaling down a hydrofoil. This work sheds light on the issues of different scaling effects and proposes a method to perform model scale testing of a hydrofoil. This report is an outcome of a master’s thesis project within Naval Architecture and Aerospace Engineering at Chalmers University of Technology. The project aims to evaluate different scaling effects on a horizontal hydrofoil and develop a feasible methodology to test foil performance in a towing tank. Limiting factors of the towing tank are identified and flow effects relative to submergence depth and testing velocity are investigated in the Computational Fluid Dynamics software STAR CCM+. The results build on a verified solver setup by conducting a turbulence model study. The effects of varying submergence depth and velocity is investigated using a generic profile Eppler 818. The characteristics of a wave is shown to have a significant effect on lift.