Download or read book Contribution l tude de la combustion derri re un choc oblique hypersonique written by LACHEBOUR.. HAMADA and published by . This book was released on 1992 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'OBJET DE CE TRAVAIL EST L'ETUDE DE L'EXISTENCE ET DU POSITIONNEMENT DE LA COMBUSTION SOUS FORME DE DETONATION OU DE FLAMME DETACHEE DERRIERE DES ONDES DE CHOC OBLIQUES HYPERSONIQUES (DE NOMBRE DE MACH VARIANT DE 3 A 10) DANS UN MILIEU REACTIF GAZEUX. LA TECHNIQUE DE PRODUCTION DES ONDES DE CHOC OBLIQUES CONSISTE EN L'EXPANSION LATERALE DES PRODUITS DE COMBUSTION DERRIERE UNE ONDE DE DETONATION NORMALE CHAPMAN-JOUGUET D'UN MILIEU PRIMAIRE DANS UN MILIEU SECONDAIRE ADJACENT, MILIEU DE L'ETUDE. LES DEUX MILIEUX SONT SEPARES INITIALEMENT PAR UN FILM DE MYLAR DE TRES FAIBLE EPAISSEUR. LA DEFLECTION DE CE FILM SOUS L'ACTION DES PRODUITS DE DETONATION DU MILIEU PRIMAIRE, CREE UN DIEDRE SE PROPAGEANT A LA MEME VITESSE QUE L'ONDE DE DETONATION CHAPMAN-JOUGUET DE CE MILIEU. L'ETUDE THEORIQUE EFFECTUEE SUR L'INTERACTION DES DEUX MILIEUX EST BASEE SUR UN MODELE DE CALCUL FAISANT INTERVENIR LA THEORIE BIDIMENSIONNELLE DES ECOULEMENTS HYPERSONIQUES ET COMPRESSIBLES POUR DECRIRE LES DIFFERENTES CONFIGURATIONS STATIONNAIRES POSSIBLES AU MOYEN DE POLAIRES DE CHOC ET DE DETONATION D'UNE PART ET DE DETENTE DE PRANDTL-MEYER D'AUTRE PART. L'ETUDE EXPERIMENTALE MET EN EVIDENCE DIFFERENTS REGIMES, STATIONNAIRES OU NON, DE LA COMBUSTION A SAVOIR LA DETONATION OBLIQUE ET LA FLAMME TURBULENTE INITIEE A LA TETE DU DIEDRE ET S'ELOIGNANT DU CHOC, REGIMES DONT L'ETABLISSEMENT DEPEND TRES FORTEMENT DE LA CINETIQUE CHIMIQUE DES MILIEUX ETUDIES. CONCERNANT LES REGIMES DE DETONATIONS STATIONNAIRES ET CERTAINS REGIMES DE FLAMMES DETACHEES, LA PREVISION DU MODELE THEORIQUE S'EST AVEREE BONNE

Download or read book Etude des r gimes de combustion induite par une onde de choc oblique hypersonique written by Christophe Viguier and published by . This book was released on 1996 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: LA PROPULSION D'ENGINS A GRAND NOMBRE DE MACH (CONCEPT DU SUPERSTATOREACTEUR) OU L'ACCELERATION DE PROJECTILE A GRANDE VITESSE (CANON CHIMIQUE) NECESSITE LA CONNAISSANCE DES MECANISMES DE LA COMBUSTION SUPERSONIQUE INDUITE PAR UNE ONDE DE CHOC OBLIQUE. DANS CETTE ETUDE EXPERIMENTALE, NOUS CHERCHONS A ETABLIR COMMENT ET DANS QUELLES CONDITIONS S'INITIENT ET SE STABILISENT LES DIFFERENTS REGIMES DE COMBUSTION DERRIERE UNE ONDE DE CHOC OBLIQUE. AFIN DE SE RAPPROCHER DES CONDITIONS DE FONCTIONNEMENT D'UN ENGIN REEL, NOUS NOUS SOMMES LIMITES A L'ETUDE DES DEUX MELANGES STOECHIOMETRIQUES H#2-AIR ET CH#4-AIR A M VOISIN DE 6, INITIALEMENT AU REPOS ET A LA TEMPERATURE DE 293 K. DE MANIERE GENERALE, LA COMBUSTION SUPERSONIQUE INDUITE PAR UNE ONDE DE CHOC OBLIQUE, PREND LES DEUX FORMES DE BASES SUIVANTES: (I) UNE FLAMME TRES TURBULENTE INITIEE A LA TETE DU DIEDRE ET DECOUPLEE DU CHOC, (II) UNE DETONATION OBLIQUE PLUS OU MOINS DETACHEE DU DIEDRE. UNE PREMIERE APPROCHE SIMPLE BASEE SUR L'ANALYSE DES POLAIRES DE CHOC ET DE DETONATION DU MELANGE ETUDIES PERMET DE PRECISER LES SOLUTIONS STATIONNAIRES POSSIBLES DE LA PROPAGATION SUPERSONIQUE D'UN DIEDRE. LA DIFFERENCE DE COMPORTEMENT DES DEUX MELANGES A ETE MISE EN EVIDENCE SUR LEUR APTITUDE A SUPPORTER OU NON UNE ONDE DE DETONATION OBLIQUE. DANS LE CAS DU MELANGE H#2-AIR, POUR LEQUEL ON OBSERVE L'INITIATION RETARDEE DE LA DETONATION OBLIQUE, NOUS MONTRONS QUE LE DELAI D'APPARITION DE CELLE-CI VARIE COMME LE TEMPS D'INDUCTION CHIMIQUE DE LA REACTION. LA STRUCTURE OBSERVEE A FAIT L'OBJET D'UNE COMPARAISON AVEC UNE SIMULATION BIDIMENSIONNELLE D'UN ECOULEMENT REACTIF SUPERSONIQUE COUPLEE AVEC UNE CINETIQUE CHIMIQUE COMPLEXE. CETTE COMPARAISON A PERMIS D'ANALYSER LES PHENOMENES ASSURANT LA TRANSITION D'UN REGIME CHOC-FLAMME OBLIQUE VERS LE REGIME DE DETONATION OBLIQUE. ENFIN UNE DERNIERE PARTIE DE L'ETUDE EST CONSACREE A L'INFLUENCE DE L'INJECTION LOCALE TURBULENTE SUR L'INITIATION ET LA STABILISATION DES REGIMES DE COMBUSTION DEJA OBSERVES LORSQUE LE MILIEU ETAIT INITIALEMENT AU REPOS

Download or read book Contribution l tude de la combustion supersonique written by Olivier Guérineau and published by . This book was released on 1997 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: La combustion supersonique est bien adaptée à la propulsion des véhicules hypersoniques aérobies. Le statoréacteur àcombustion supersonique (superstatoréacteur) surclasse les systèmes plus classiques (turboreacteur, statoreacteur à combustion subsonique) lorsque le Mach de vol dépasse 7. La conception des foyers à combustion supersonique pose des problèmes fondamentaux et techniques difficiles. Des questions spécifiques posées par l'accrochage par une onde de choc au sein d'un mélange hydrogène-air. Une cinétique réactionnelle complexe est sélectionnée puis utilisée. Elle rend compte des principaux phénomènes caractérisant la combustion de l'hydrogène dans l'air : temps d'allumage, limites d'explosibilité d'un mélange stœchiométrique. Un code volumes finis, résolvant les équations de Navier-Stokes réactives, est adapté aux calculs de combustion supersonique. Les méthodes numériques employées sont exposées : en particulier la description des flux d'Euler par des solveurs approchés de Riemann (méthode de Roe, méthode des courbes de choc, flux d'Osher). Ces méthodes précises se sont cependant révélées délicates à utiliser du fait de la raideur du système. Deux configurations principales de calcul ont été dégagées d'une étude bibliographique des expériences et calculs de combustion faisant intervenir des chocs. Une étude numérique de l'allumage d'une flamme hydrogène-air derrière un disque de mach est présentée pour la première fois. Elle permet d'affirmer que les ondes observées dans les expériences précédemment citées sont des ondes de choc, et non pas des ondes de détonation. La position du disque de mach dépend de la modélisation employée au cours des calculs. La seconde configuration est celle d'un dièdre plonge dans un écoulement prémélangé air-hydrogène d'un nombre de Mach de 3. Les résultats prouvent que des détonations obliques fortes peuvent être stables, cette configuration constituant un mode d'accrochage envisageable pour une flamme. Ils montrent de plus les limites de la théorie classique des polaires de détonation aux hypothèses trop simplificatrices (propriétés thermodynamiques constantes). Enfin un calcul reprenant la première configuration à une température plus élevée met en évidence l'analogue de la réflexion de Mach pour des ondes de détonation. Ces études montrent qu'un tel système peut-être instable. Ces études concernant des situations pouvant se produire au sein de la chambre de combustion d'un superstatoréacteur, mettent en évidence des phénomènes dont il faut tenir compte.

Download or read book Contribution l tude des ondes de choc et de combustion sph riques divergentes dans les gaz written by Jacques Brossard (Physicien.) and published by . This book was released on 1970 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book IUTAM Symposium on Variable Density Low Speed Turbulent Flows written by Louis Fulachier and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: The General Assembly of the International Union of Theoretical and Applied Mechanics in its meeting on August 28, 1994, selected for 1996 only four Mechanics Symposia, of which ours is the only one related to Fluid Mechanics: Variable Density Low Speed Turbulent Flows. This IUTAM Symposium, organized by the Institut de Recherche sur les Phenomenes Hors Equilibre (Marseille), is the logical continuation of the meetings previously organized or co-organized - on the French or European level, such as Euromech 237, Marseille, 1988 - by the same research group ofMarseille. This meeting focused specifically on the structure of turbulent flows in which density varies strongly : the effect of this variation on the velocity and scalar fields is in no sense negligible. We were mainly concerned with low-speed flows subjected to strong local changes of density as a consequence of heat or mass transfer or of chemical reactions. Compressible turbulent flows - such a!" supersonic ones - were also considered in order to underline their similarities to and their differences from low-speed variable density flows.

Download or read book Satellite Situation Report written by Goddard Space Flight Center. Office of Public Affairs and published by . This book was released on 1977 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Antifascisms written by David Ward and published by Fairleigh Dickinson Univ Press. This book was released on 1996 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is an in-depth analysis of three of the most crucial years in twentieth-century Italian history, the years 1943-46. After more than two decades of a Fascist regime and a disastrous war experience during which Italy changed sides, these years saw the laying of the political and cultural foundations for what has since become known as Italy's First Republic. Drawing on texts from the literature, film, journalism, and political debate of the period, Antifascisms offers a thorough survey of the personalities and positions that informed the decisions taken in this crucial phase of modern Italian history.

Download or read book Space Debris written by Heiner Klinkrad and published by Springer Science & Business Media. This book was released on 2006-09-01 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: The future evolution of the debris environment will be forecast on the basis of traffic models and possible hazard mitigation practices. The text shows how large trackable objects will have re-entry pinpointed and predictions made on related risk assessment for possible ground impact. Models will also be described for meteoroids which are also a prevailing risk.

Download or read book Fresh from the Farm 6pk written by Rigby and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sisters Super Creeps and Slushy Gushy Love Songs written by Karen McCombie and published by . This book was released on 2011 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ally knows her super-efficient big sis Linn finds their chaotic family a bit ... exasperating. But when Linn falls for Q, the tearaway lead singer in a local band, all her sensible ways go out of the window. Everyone else can see that Q's a creep, but does Ally have the courage to burst Linn's heart-shaped bubble?

Download or read book Trichier written by Alessandra Ceretto and published by Lulu.com. This book was released on with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fletcherism What It Is Or How I Became Young at Sixty written by Horace Fletcher and published by DigiCat. This book was released on 2022-06-02 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Fletcherism: what it is: or, How I became young at sixty" by Horace fletcher is a fascinating book on nutrition and diet. The author here relates briefly the story of his regeneration, of how he rescued himself from the prospect of an early grave, and brought himself to his present splendid physical and mental condition. He tells of the discovery of his principles, which have helped millions of people to live better, happier, and healthier lives. The book is a good fit if you are concerned about health and diet.

Download or read book Auxiliary power systems papers presented at the Propulsion and Energetics Panel 61st B specialists meeting held in Copenhagen Denmark 30 31 May 1983 written by AGARD. and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Kumba Africa written by Sampson Ejike Odum and published by iUniverse. This book was released on 2020-11-03 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: ‘KUMBA AFRICA’, is a compilation of African Short Stories written as fiction by Sampson Ejike Odum, nostalgically taking our memory back several thousands of years ago in Africa, reminding us about our past heritage. It digs deep into the traditional life style of the Africans of old, their beliefs, their leadership, their courage, their culture, their wars, their defeat and their victories long before the emergence of the white man on the soil of Africa. As a talented writer of rich resource and superior creativity, armed with in-depth knowledge of different cultures and traditions in Africa, the Author throws light on the rich cultural heritage of the people of Africa when civilization was yet unknown to the people. The book reminds the readers that the Africans of old kept their pride and still enjoyed their own lives. They celebrated victories when wars were won, enjoyed their New yam festivals and villages engaged themselves in seasonal wrestling contest etc; Early morning during harmattan season, they gathered firewood and made fire inside their small huts to hit up their bodies from the chilling cold of the harmattan. That was the Africa of old we will always remember. In Africa today, the story have changed. The people now enjoy civilized cultures made possible by the influence of the white man through his scientific and technological process. Yet there are some uncivilized places in Africa whose people haven’t tested or felt the impact of civilization. These people still maintain their ancient traditions and culture. In everything, we believe that days when people paraded barefooted in Africa to the swarmp to tap palm wine and fetch firewood from there farms are almost fading away. The huts are now gradually been replaced with houses built of blocks and beautiful roofs. Thanks to modern civilization. Donkeys and camels are no longer used for carrying heavy loads for merchants. They are now been replaced by heavy trucks and lorries. African traditional methods of healing are now been substituted by hospitals. In all these, I will always love and remember Africa, the home of my birth and must respect her cultures and traditions as an AFRICAN AUTHOR.

Download or read book Bacchantes written by Euripides and published by . This book was released on 1885 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aircraft Fire Safety written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Propulsion and Energetics Panel. Symposium and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Conference Proceedings contains 38 papers presented at the Propulsion and Energetics Panel 73rd Symposium on 'Aircraft Fire Safety' which was held 22 - 26 May 1989 in Sintra, Portugal. The Symposium was arranged in the following sessions: Review of Fire-Related Aircraft Accidents (3); Fire Safety Standards and Research Programmes (6); Aircraft Internal Fires (9); Aircraft External Fires (2); Fire Safety of Military Weapon Systems (3); Fire Hardening by Advanced Materials and Structural Design (8); Passenger Behaviour in Emergency Situations (3); and Passenger Protective Equipment (4). The Technical Evaluation Report and and Addendum are included at the beginning of the Proceedings. Questions and answers of the discussions follow each paper. The last AGARD review on the subject took place in a Specialists' Meeting in 1975, followed by a Working Group Report in 1979 and Lecture Series in 1982. The purpose of the Symposium was a review of the present state-of-the-art and of the last improvements. Although the safety standards in aviation are already very high, there is still room for improvements. They are listed in the Conclusions and Recommendations of the Technical Evaluation Report and in the Addendum.

Download or read book Heat Transfer and Cooling in Gas Turbines written by and published by . This book was released on 1985 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: