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Thermal signature reduction through liquid nitrogen and water injectionGuarnieri, Jason Antonio 17 February 2005 (has links)
The protection of aircraft against shoulder fired heat seeking missiles is of growing concern in the aviation community. This thesis presents a simple method for shielding the infrared signature of a jet engine from heat seeking missiles. The research efforts investigated two approaches to shield the thermal signature of the Noel Penny Type 401 turbojet at the Texas A&M University Propulsion Lab Test Cell. First, liquid nitrogen was injected through a manifold at a flow rate equivalent to the flow rate of exhaust gases, producing a small temperature reduction in the exhaust but no infrared shielding. Second, water was injected at a flow rate of 13% of the flow of exhaust gases, producing a greater temperature reduction and some shielding. Water was then injected through a manifold at a flow rate of 118% of the flow rate of exhaust gases, producing a substantial reduction in temperature and complete shielding of the infrared signature. Additionally, numerical simulations were performed using FLUENT to support these experiments. Results are presented in the form of thermocouple data and thermal images from the experiments, and in the form of temperature contours and streamtraces from the simulations.
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Thermal signature reduction through liquid nitrogen and water injectionGuarnieri, Jason Antonio 17 February 2005 (has links)
The protection of aircraft against shoulder fired heat seeking missiles is of growing concern in the aviation community. This thesis presents a simple method for shielding the infrared signature of a jet engine from heat seeking missiles. The research efforts investigated two approaches to shield the thermal signature of the Noel Penny Type 401 turbojet at the Texas A&M University Propulsion Lab Test Cell. First, liquid nitrogen was injected through a manifold at a flow rate equivalent to the flow rate of exhaust gases, producing a small temperature reduction in the exhaust but no infrared shielding. Second, water was injected at a flow rate of 13% of the flow of exhaust gases, producing a greater temperature reduction and some shielding. Water was then injected through a manifold at a flow rate of 118% of the flow rate of exhaust gases, producing a substantial reduction in temperature and complete shielding of the infrared signature. Additionally, numerical simulations were performed using FLUENT to support these experiments. Results are presented in the form of thermocouple data and thermal images from the experiments, and in the form of temperature contours and streamtraces from the simulations.
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Compositional Effect on Low-Temperature Transient Liquid Phase Sintering of Tin Indium Solder PasteJohn Osarugue Obamedo (11250306) 03 January 2022 (has links)
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<p>Transient liquid phase sintering (TLPS) technologies are potential low-temperature solders for
sustainable replacements of lead-based solders and high-temperature lead-free solders. Compared to solid-state sintering and lead-free solders, TLPS uses lower temperatures
and is, thus, suitable for assembling temperature-sensitive components. TLPS is a non-
equilibrium process and determining the kinetics is critical to the estimation of processing times
needed for good joining. The tin-indium (Sn-In) system with a eutectic temperature of 119°C is
being considered as the basis for a TLPS system when combined with tin. Most models of TLPS
include interdiffusion, dissolution, isothermal solidification, and homogenization and are based
on simple binary alloys without intermediate phases. The Sn-In system has two intermediate
phases and thus the reaction kinetics require additional terms in the modeling. Differential
Scanning Calorimetry (DSC) has been used to measure the response of Sn-In alloys during the
transient liquid phase reaction. Preparation of tin indium alloys for microstructural analysis is
challenging due to their very low hardness. This study uses freeze-fracturing of the tin indium
alloys to obtain sections for microstructural analysis. The combination of DSC and
microstructure analysis provides information on the reaction kinetics. It was observed that the
solid/liquid reaction does not proceed as quickly as desired, that is, substantial liquid remains
after annealing even though the overall composition is in the single-phase region in the phase
diagram. </p>
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