A facility was designed to provide high-enthalpy, hypersonic flow to a detonation chamber. Preliminary investigation identified 1300 K and Mach 5 as the total temperature and Mach number require to stabilize an oblique detonation wave inside the detonation chamber. Vitiated-air heating was the preheating method chosen to meet these capabilities. The vitiator facility heats compressed air while still retaining about 50% of the original oxygen content. Schlieren flow visualization and conventional photography was performed at the exit plane of a choke plate, which simulated the throat of a converging-diverging nozzle. A shock diamond formation was observed within the jet exhausting out of the choke hole. This is a clear indication that the facility is capable of producing hypersonic flow. A stoichiometric propane-air mixture was burned inside the combustion chamber. A thermocouple survey measured an average temperature of 1099 K at the exit plane of the mixing chamber; however, the actual temperature is likely higher than this, because cool, ambient air could be seen mixing with the hot, vitiated air near the exit plane. Because the adiabatic flame temperature of propane-air is lower than that of hydrogen-air, if hydrogen is used to vitiate the air, the facility is capable of meeting the 1300-K objective.

This paper aims to study how varying crossflow burning temperatures from 1100 C to 1800 C affect the liquid droplet breakup, size distribution, and atomization of a liquid water jet injected into a vitiated crossflow. The LJIC injection mechanism was implemented using the high-pressure axially staged combustion facility at the University of Central Florida. The measurement devices used to gather particle data from the exhaust plume were the TSI Aerodynamic Particle Sizer (APS), which measures particles between 0.523 µm and 20 µm, and the Sensirion SPS30 (SPS30), which measures particles between 0.3 µm and 10 µm. Both measurement devices were placed 3 ft away from the choked exit. Table 3 shows that the 1800 C crossflow temperature behaved as predicted by having the largest particle distribution of 67.97% and the largest particle count of 19,301 at 0.523 µm. The 1100 C crossflow produced the second-largest normalized particle count of 66.69% and raw particle count of 20,209 at 0.523 µm. This result is contrary to the original hypothesis because it shows that the relationship between temperature and particle count is non-linear and that many other factors must be at play in the atomization process, such as the droplet distribution at the nano level. The SPS30 was used to compare the particle size distributions between a 1500 C and 1800 C crossflow. Acquiring number concentration data for particles up to 10 µm in size, the 1800 C crossflow had a distribution peak at 802.76416 N/cm3, and the 1500 C crossflow had a peak of 867.28272 N/cm3. For the 0.5 µm peak, The 1800 C had a 10 µm particle size distribution peak at 674.27.76416 N/cm3, and the 1500C crossflow had a peak of 730.501 N/cm3. The decreased number concentration from 1500 C to 1800 C case grants the water particles in the 1800 C crossflow increased surface area, which allows for increased heat exposure from the vitiated crossflow [7]. Despite some nonlinear particle count results, the highest crossflow temperature of 1800 C produces the best atomization results by reducing the total particle count and having the largest collection of particles at the lowest detectable particle size of 0.523 µm.

Participant d'une nature mixte, contractuelle par sa source, juridictionnelle par son objet, la transaction permet ainsi aux parties de terminer une contestation née ou prévenir une contestation à naître. Elle présente une utilité remarquable pour la matière administrative. La transaction, notion de droit civil empruntée par le juge administratif, a donné lieu à des interprétations prétoriennes diverses. Le droit n'étant pas figé, le juge administratif, sous couvert d'une philosophie propre, a oeuvré pour la préservation de ses intérêts en se détachant progressivement des principes civils du contrat de transaction. L'expression de « transaction administrative » vise le fait que la transaction est conclue par ou au nom d'une personne publique. Celle-ci peut cependant être un contrat de droit privé ou un contrat administratif. Certes, l'expression « matière administrative » peut être entendue au sens large et au sens strict. Le contentieux de la transaction est en plein essor. Depuis longtemps déjà le droit public emprunte les règles civiles du contrat de transaction relevant de régimes juridiques différents. Des difficultés sérieuses subsistent cependant. Aussi, il convenait de démontrer pourquoi et comment le juge administratif a entrepris une clarification de l'état du droit de la transaction en matière administrative. L'étude a été l'occasion de distinguer la fonction d'adaptation et de systématisation du juge administratif, là où cette différenciation n'était que rarement envisagée. / Participant of a mixed nature, by its contractual source, legal in its object, the transaction and allows the parties to end a dispute arising or prevent future litigation. It has a remarkable usefulness for administrative matters. The transaction, civil law concept borrowed by the administrative judge, gave rise to various interpretations praetorian. The law is not static, the administrative judge, under cover of a personal philosophy, worked to preserve its interests gradually detaching civilians principles of contract transaction. The term "administrative transaction" refers to the fact that the transaction is entered into by or on behalf of a public entity. This can however be a private contract or an administrative contract. Admittedly, the term "administration" can be interpreted broadly and narrowly. Litigation of the transaction is booming. Has long been public law borrows the civil rules of contract transaction subject to different legal regimes. Serious difficulties remain. Also, it was necessary to demonstrate why and how the administrative judge undertook a clarification of the law of the transaction in administrative matters. The study was an opportunity to distinguish the function of adaptation and systematization of administrative courts, where this differentiation was rarely considered.