Pusat Pengajian Kejuruteraan Aeroangkasa - Tesis

Browse

Now showing 1 - 5 of 45

Conceptual design of small scale unmanned aerial vehicle (predator)
(2010-05-01)
Abd Manap, Amir
Nowadays, a UAV is an important vehicle. Many countries already have their own UAV, even Singapore. Malaysia already has RazakSAT, so it is possible to have a UAV developed by Malaysian. The use of the UAV is everywhere because it gives a lot of benefit which include cost reduction, increment in safety level and simplification of hard tasks. The main objective of this thesis is to generate a 3D model of Predator and compare it with the actual Predator that exists nowadays. Seven pivot points was suggested by Anderson[10] for conceptual design which are mission requirements, first estimation of the airplane weight, critical performance parameters, layout configuration, better weight estimation, performance analysis and optimization. Each single result was compared to the Predator’s performance and was discussed why there is a difference between those two UAV’s parameters. This UAV was designed to operate in Malaysia so it has different parameters compared to Predator developed by USAF. The project outcome is a 3D model of the Predator and it is a bit different from the actual Predator but perhaps the layout configuration will changes in preliminary and detail design. The result obtained is acceptable and it is possible for Malaysian to have own UAV. It will be used in preliminary design which aerodynamic, structural and control system analysis take place. Finally, the design process will enter detail design also called nuts and bolts phase which size, numbers and location of fasteners will be determined before the fabrication takes place.
Performance study of conventional savonius hydrokinetic turbine with two flat deflectors
(2022-03-01)
Salleh, Mohd Badrul
Hydrokinetic turbines (HKT) have great potential for providing sustainable energy. Savonius HKT is considered the best option for low-cost applications due to its simplicity and ability to operate under low flow rates. The deflectors have been shown to improve the low performance of the turbine. However, the use of two deflectors for a conventional Savonius HKT, particularly in flows with low and varying speeds is still lacking. This research aims to improve the performance of the conventional Savonius HKT by incorporating two flat deflectors. The power performance of the turbine was investigated in a wind tunnel with respect to three deflector parameters: angle, longitudinal position, and height. First, the turbine performance was evaluated on 2-bladed and 3-bladed turbine models with 30 combinations of the deflector angles of the advancing and returning blades, 𝛿𝐴 and 𝛿𝑅, respectively at 7.0 m/s airflow speed (equivalent water flow speed of 0.40 m/s). The better-performing 2-bladed turbine model was then selected for further investigation on 9 combinations of the deflector longitudinal positions of the advancing and returning blades, 𝑋𝐴⁄𝑅 and 𝑋𝑅⁄𝑅, respectively, followed by 3 different deflector heights: 0.5𝐻, 1𝐻, and 1.5𝐻. The experiments on the 2-bladed turbine were then repeated at various Reynolds numbers, 𝑅𝑒 ranging from 9.27 × 104to 1.48 × 105. The flow patterns surrounding the 2-bladed turbine were visualized using smoke generators to provide additional insights into the flow behaviors across various deflector configurations. The wind tunnel results were validated (within the experimental errors) by testing the 2-bladed turbine in a water channel for the same parametric variations of the deflectors with dynamically similar flow conditions. The maximum coefficient of power, 𝐶𝑃𝑚𝑎𝑥 of the 2-bladed turbine model with the two deflectors was 14% higher than that of the 3-bladed turbine. The 2-bladed turbine model exhibited the highest 𝐶𝑃𝑚𝑎𝑥 of 0.210 with 61.54% improvement relative to that of the turbine without the deflectors at the optimal deflector angles of 𝛿𝐴 = 30° and 𝛿𝑅 = 90°. The 𝐶𝑃𝑚𝑎𝑥 was further increased to 0.261 with 100.77% improvement at the optimal deflector longitudinal positions of 𝑋𝐴⁄𝑅 = −0.500 and 𝑋𝑅⁄𝑅 = −1.204, and at the optimal deflector height of 1𝐻. These optimal deflector configurations remain unchanged as 𝑅𝑒 increases, regardless of the increment in the turbine performance. In-depth investigation using flow visualization revealed that the deflector configurations influenced the surrounding flow patterns but were independent of variations in 𝑅𝑒. Optimizing the deflector configurations effectively directed the flow towards the advancing blade while preventing it from impinging on the returning blade, resulting in an increase in the positive net torque and thus the performance of the turbine. Findings from this research demonstrated the efficacy of using two flat deflectors in solving the problem of low power performance of the conventional Savonius turbine.
Automated route planning with obstacle avoidance for unmanned aerial systems
(2021-10-01)
Debnath, Dipraj
Autonomous unmanned aerial systems (UAS) are increasingly becoming a major focus of study in both academia and industrial sectors. With the aim of resolving the path planning issue, this study adopts the travelling salesmen problem (TSP) and solve it by applying an Improved Genetic Algorithm (IGA) that can identify the optimal way in terms of both distance and time. The outcome shows that the approach of the GA is relatively effective in finding not only the optimum path distance but also minimize and in some cases eliminate the crossing paths. Another value-added feature for UAS is to be equipped with a reliable obstacle detection and avoidance system especially when it operates in low-flying zone. The obstacles can be considered as a hindrance to the UAS flight path, and the algorithm should detect and avoid it through avoidance waypoints. The avoidance approach proposes here combines the linear equation and locating its intersection points between the diagonal lines within the square area. Based on that, the square areas are used to guide the algorithm to compute new safe avoiding waypoints. The size of the square areas is based on the safe avoidance distance defined based on the UAS specification such as size, speed and UAS type. All Algorithms here are created in MATLAB and then tested and assessed in several scenarios where the UAS must avoid obstacles during operation. The result from this research shows that the algorithms can provide reasonable solutions in finding the optimal path and avoiding obstacles based on the scenarios. Therefore, this approach is very helpful for any UAS that need a pre-plan mission prior to the actual flight operation.
Three dimensional computational modelling of biofuels combustion characteristics and its effect on turbine blade structure
(2022-05-01)
Sim, Sing Mei
Biofuel has been identified to reduce pollution generated by an aircraft engine. This study is conducted to assess 1) biofuels combustion characteristics and 2) biofuel hot combustion gases effect on turbine blade structure at take-off, top of climb and cruise. The biofuels chosen in this study are Jatropha Bio-synthetic Paraffinic Kerosene (JSPK) and Camelina Bio-synthetic Paraffinic Kerosene (CSPK). The fuels were evaluated as pure (100%) and blend (50%) with Jet–A. The assessments were performed computationally via Computational Fluid Dynamic (CFD) and Fluid Structure Interaction (FSI) available in ANSYS. A comparison of combustion characteristics namely d2 law and penetration length of biofuels with Jet–A through the incorporation of fuel properties and actual combustor inlet data at various flight trajectories is obtained. The usage of biofuels in combustion provides up to a 15% maximum temperature reduction, and up to 83% reduction in penetration length. JSPK consumes less fuel and has better evaporation rate while producing similar thrust with Jet-A. JSPK has least improvement of fatigue life cycles due to consistent combustion characteristics with Jet-A. CSPK shows the highest improvement in fatigue life cycle during take-off and cruise due to lower temperature at the turbine inlet, thus lower stress and strain at the turbine blade section are obtained. The study generally indicates a correspond relation on temperature effect between combustion and turbine blade. The trend might contradict for a particular evaluation due to the dependency on the boundary condition that correspond to the properties of the fuel tested.
River feature morphology using k-means clustering in image segmentation of uav imagery
(2022-06-01)
Iftekar, Ansari Emaad
In Malaysia, flood disaster is considered to be an annual catastrophic disaster due to their consistent occurrence over the years. In this regard, flood hazard assessment models play a significant role, as they form the central component of the flood risk analysis system. With the expeditious evolution of computer techniques, processing of satellite and unmanned aerial vehicle (UAV) images for river hydromorphological feature detection and flood management have gathered pace in the last two decades. Different image processing algorithms and artificial neural networks were implemented in past studies for the monitoring and classification of river features. This study presents the application of the K-means image segmentation algorithm with image thresholding to quantify variation in river surface flow areas and vegetation growth along Kerian River, Perak, Malaysia. The river characteristic recognition directly or indirectly assisted in studying river behaviour and flood monitoring. Dice similarity coefficient (DSC) and Jaccard index were numerated between thresholded images that were clustered using the K-means image segmentation algorithm and segmented images. Based on the quantitative evaluation, a Dice similarity coefficient and Jaccard index of up to 97.86% and 94.36% were yielded for flow area and vegetation calculation. Thus, the proposed technique was functional in evaluating river characteristics with reduced errors. With minimum errors, the proposed technique can be utilized for quantifying agricultural areas and urban areas around the river basin. Regression analysis of suspended sediment concentration and Hue Saturation Value (HSV) color space components of UAV captured river surface images were also performed in the proposed study. It was concluded using various statistical test that the correlation between the suspended sediment concentration and HSV components of UAV captured river water surface images were non-linear. Furthermore, non-linear correlation analysis would be needed in future for obtaining an accurate relationship between the suspended sediment concentration and HSV components of aerial images.

Browse

Recent Submissions