Abstract: A large number of theoretical and experimental studies have shown that the performance of kerosene combustion increases significantly if combustion is being assisted by the addition of hydrogen to the fuel/air mixture during the combustion process. It reduces the amount of CO, CO2 and NOx emissions, while increasing the flame stability limits. It also helps in bruning fuel/air mixtures at much leaner equivalence ratios. The same principle could be applied to gain benefits in gas turbine combustors. Hydrogen for this purpose could be produced by the reforming of hydrocarbon fuels using a reformer module. This paper presents key hydrogen reforming technologies which, by implementation in gas turbine combustors, hold potential for improving both their performance and service life.
Abstract: The rapid growth of the aviation sector around the globe has witnessed an overwhelming impact on fossil fuel resources. With the implementation of stricter environmental laws over emissions by conventional jet fuels, growing demand for research on alternative fuels has become imperative. One-hundred percent Synthetic Paraffinic Kerosene (SPK) and Fully Formulated Synthetic Jet Fuel have surfaced as viable alternatives for gas turbine engines due to their similar properties as that of Jet Fuel. This paper presents results from an experimental study performed on a small gas turbine engine, comparing emissions performance and vibrations for conventional Jet A-1 Fuel, thermally stressed 100% SPK and Fully Formulated Synthetic Jet Fuel. Different vibration frequencies, power spectra were observed for different fuels. Gaseous emissions observed were nearly the same, whereas, significant changes in particulates emissions were observed.
Abstract: Four sample space launch missions were designed using rotating momentum transfer tethers (bolos) within low Earth orbit and a previously unknown phenomenon of “aerospinning” was identified and simulated. The momentum transfer tethers were found to be only marginally more efficient than the use of chemical rocket boosters. Insufficient power density of modern spacecrafts was identified as the principal inhibitory factor for tether usage as a means of launch-assistance, with power densities at least 10 W/kg required for effective bolos operation.
Abstract: The number of small spacecraft development programs in the United States and worldwide have increased significantly over the course of the last 10 years. This paper analyzes reasons for the growth in these programs by assessing what student participants hope to gain from their participation. Participants in the OpenOrbiter Small Spacecraft Development Initiative at the University of North Dakota were surveyed at the beginning of an academic year to determine why they were planning to participate in the program again or join and participate for the first time. This paper presents the results of this survey.
Abstract: A pseudo-sliding mode control synthesis procedure discussed previously in the literature is applied to the design of a control system for a nonlinear model of the NASA Langley Generic Transport Model. The complete vehicle model is included as an appendix. The goal of the design effort is the synthesis of a robust control system to minimize aircraft loss-of-control by preserving fundamental pilot input—system response characteristics across the flight envelope, here including the possibility of actuator damage. The design is carried out completely in the frequency domain and is described by a ten-step synthesis procedure, also previously introduced it the literature. Five different flight tasks are considered in computer simulations of the completed design demonstrating the stability and performance robustness of the control system.