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Browsing by Author "Santos, Ana Teresa Rodrigues de Almeida"

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  • Design, Construction, and Testing of a Gasoline Valveless Pulsejet Engine
    Publication . Santos, Ana Teresa Rodrigues de Almeida; Brojo, Francisco Miguel Ribeiro Proença
    Interest in pulsejet engines has been reignited, especially with the growth of new technologies in the aeronautical industry. This type of propulsion was extensively used during World War II; however, its application in civilian aviation was discarded due to high noise levels and excessive vibrations. Nonetheless, owing to its simple and lightweight design, it has propelled the implementation of pulsejet engines in the Unmanned Aerial Vehicles (UAVs) market. The complex nature of the processes involved in this jet engine makes the analysis fragmented, demanding a deeper understanding of its operation. Thus, to contribute to the demystification of this type of propulsion, a practical study was conducted at the Department of Aerospace Sciences at UBI on a valveless Chinese-type pulsejet. The present dissertation investigated the behaviour of a valveless pulsejet when fueled by liquid and gaseous fuel, allowing for comparison in both scenarios. One test was conducted using propane, and three tests were carried out using gasoline, varying the mass flow rate. This research also involved designing and constructing an injection system capable of atomizing the liquid fuel. However, the engine operating with gasoline was less efficient than when operated with propane. The TSFC values for gasoline exceeded 1 kg/N.h, while for the propane test, the fuel consumption rate to achieve the measured thrust was only 0.574 kg/N.h. During each test, data regarding thrust force, intake temperature, exhaust temperature, and operational frequency were recorded. All parameters in the gasoline tests decreased due to the specific characteristics of gasoline, particularly the burning speed, but mostly due to the injection pressure. The liquid fuel burner required more pressure to break the gasoline into smaller particles to improve the interaction between the fuel and the air. Nonetheless, the self-sustaining effect was achieved with both the propane and gasolineoperated engines, although unstable combustion was observed in the latter.
    2024-02-22Master thesis Open access Show more