Conference Publications
Permanent URI for this collection
Browse
Browsing Conference Publications by browse.metadata.impactarea "Aeronautic Systems"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
Item The first step towards decarbonized air mobility in South Africa: A hydrogen powered unmanned aerial vehicle(2022-11) Jamison, Kevin A; Naidoo, Purusha; Ramotsabi, KatlehoThe South African government is investing in the use of hydrogen fuel as a pathway towards decarbonising transport sectors. Hydrogen is likely to be a viable option for decarbonising air transport and it is being investigated intensively around the world. The merits of hydrogen as an air transport fuel relative to other alternatives are discussed. To localise expertise in hydrogen powered aviation in South Africa it was decided that a small hydrogen fuel cell powered unmanned aerial vehicle (UAV) would be developed as a first step. Once hydrogen powered flight is demonstrated at the UAV scale then the expertise gained can be scaled up to the general aviation sector and ultimately, commercial aviation. A concept of the UAV and its hydrogen fuel cell propulsion unit is presented and discussed.Item The numerical aerodynamic investigation of swirling inlet flow in a vaporizer tube micro-gas turbine combustor(2022-09) Meyers, Bronwyn C; Grobler, Jan-Hendrik; Snedden, GCA combustor was designed for a 200N micro-gas turbine for the model aircraft industry using the NREC design method. Multiple designs resulted which varied in terms of annular area split configuration, hole area splits and relative hole positions. In a previous study two likely preferable designs were selected using a devised scoring method. For this study, the effect of inlet (diffuser outlet) swirl on the internal aerodynamics of the two combustor designs previously chosen was investigated using a RANS CFD analysis. For each of the two designs a set of varying flow angles was applied at the inlet to the simulation domain. The effect on the establishment of the primary zone features is of specific interest; however, the effects and consequences of the swirl throughout the combustor were investigated. Some of the results such as mass flow splits and pressure drop are already quantitative in nature, however, the evaluation of the quality of the recirculation zone, mixing and outlet plane flow are of a more qualitative nature. A scoring system was previously devised in order to apply a quantitative value to the qualitative aspects of the flow, such as Recirculation zone (Rz), Outlet and Mixing, which are initially analysed subjectively. For each feature, the designs were subjectively evaluated relative to each other and given a rating/score. This scoring methodology for ranking different combustor designs proved to be an effective method for evaluating the effect of inlet swirl on the flow features and behaviour of the chosen combustor designs and thus provide an indication of the likely performance changes to be expected. The methodology was able to indicate which of the two top designs was the better option when considering inlet swirl, however the potential for improvement was revealed when considering scoring in a global context. This study suggests that for this engine, the inlet swirl could allow for the removal of NGV before the turbine since the flow is fairly well conditioned and “pre-turned” due to the swirling flow progressing to the outlet of the combustor. The removal of the traditional NGV allows for a reduction in NGV pressure losses which compensates for the increased combustor pressure loss experienced due to increased inlet swirl.Item Selecting munition design features and operational concepts using a trade study supported by simulated operational scenarios(2021-09) Jamison, Kevin A; Roux, Jeanne M; Zwane, LindokuhleA development of an existing munition aimed at an entirely new target set was planned. A trade study was performed to identify the key design features and employment concepts that generate the optimum outcomes in a demanding operational scenario. The trade study was configured as a Multi-Attribute Tradespace Exploration (MATE) using a trade study matrix that considers the key design and operational variables to be investigated. The baseline munition concept was parameterised such that design changes are described by those key variables. For each set of tradespace variables the baseline munition design was optimised to maximise its operational range while complying with constraints and meeting the design requirements. The characteristics of each optimised munition was determined for input into a simulation model of an operational scenario modelling the operational environment and the threat systems to determine the best performing munition solution. This paper outlines the implementation of the MATE approach and the lessons learned that can be incorporated in the broader systems engineering discipline.Item A systems engineering framework for integrating stores with aircraft(2023-10) Jamison, Kevin AMilitary and some civilian aircraft need to carry stores to perform their mission. There is a huge diversity of carriage aircraft and types of stores ranging from missiles, drop tanks, space launchers, and rescue equipment. Adding stores to aircraft has a significant impact on the airworthiness of the carriage aircraft. Stores affect aircraft in multiple ways, making the integration of stores a complex multidisciplinary engineering problem that is often costly to resolve. The current regulatory and technical framework for store integration is reviewed. A systems engineering approach to store integration is presented where both aircraft and stores are designed from the outset to facilitate store integration. While some examples of this being done can be found, much still needs to be done to facilitate cost-effective store integration. Two case studies are presented and discussed showing the utility of this approach.