دانلود کتاب عناصر طراحی و توسعه‌ی هواگردهای مافوق صوت

Airbreathing hypersonic flight is a fascinating topic. Many attempts have been made to advance it in the direction of actual operation. Apart from military applications, which are not considered here, no study or project advanced far enough. Notable exceptions are the flights of the X-43A and the X-51A, which were pure experimental flight vehicles of rather small size. The last two decades of the previous century have seen a number of studies of single-stage-to-orbit (SSTO) and two-stage-to-orbit (TSTO) space transportation systems. Airbreathing propulsion in form of ramjet and scramjet propulsion did play a deciding role. Another topic with much appeal was that of long-haul airbreathing hypersonic passenger flight, with flight distances ranging up to half around the globe. Such studies extended and continue into the present century. Of particular interest remained and still remains the propulsion technology. That regards the ramjet and in particular the scramjet, and also the detonation engine concept. Basic research was and is conducted on propulsion technology and also concerning—after a, to some extent inexplicable neglect—the all deciding topic of laminar-turbulent transition of hypersonic boundary layers. The topic of realelastic versus perfect-elastic airframe structure design technology, too, has not found the needed interest. It is of very large importance when considering the partly quite large airframes of potential hypersonic airbreathers and the necessary ground testing of their static and dynamic elastic properties, this all in view of the topic of airframe-propulsion integration. Flight nowadays is considered to be hypersonic at flight Mach numbers above M 5. The ramjet-propulsion domain today is seen in the interval 3 M 7, followed by the scramjet-propulsion domain, which reaches up to M 12. Because of the rising of dynamic pressure with M , both flight domains imply flight at altitudes much higher than those of the turbojet domain. Thermal loads on the flight vehicle—depending strongly on the state of the boundary layer, either laminar or turbulent—are rising extremely with rising flight Mach number. Hence knowledge of the location, the shape and the extent of the laminar-turbulent transition zone is of utmost importance. However, this is a problem, which still is not mastered to the necessary degree. The thermal loads topic via structural aerothermoelasticity also regards the airframe and the airframe-propulsion integration. For the latter, six airframepropulsion integration (API-) types are defined in this book. All plays a deciding role also in the final flight-vehicle certification. The API-type plays an important role also regarding flyability and controllability of the airbreather under consideration. All in all it must be emphasized that it is not sufficient to create the concept of an airbreathing hypersonic aircraft or that of a globe-spanning airbreathing hypersonic cruiser. The topics design, development, ground testing, verification and finally certification before commission into service begins, are of eminent importance. Hence this book is dedicated to a sketch of relevant flight vehicle design, development and engineering issues. That to a degree is incomplete, in fact even lacking important details of some phases. In view of the urging environmental challenges one has to ask whether—civil— airbreathing hypersonic flight should still be a worthwhile topic. There are at least three answers. (1) With TSTO-systems using LH2 as propellant it could be possible to reduce the environmental impact of launch to orbit in comparison to pure rocket launch. (2) The access to space with a TSTO-system from places far in the north, which was the rationale of the German Hypersonics Technology Programme in the 1980s/1990s, is a viable reason to pursue airbreathing hypersonic flight. (3) Longhaul hypersonic passenger flight, which however, appears to be problematic in view of the said environmental impact. Regarding the design and development of hypersonic airbreathers a large number of phenomena and problems is present, which are not existing in ordinary aircraft design. Particular problems exist with the available simulation means. The designer must be aware of the potentials and the shortcomings of both the computational and experimental tools and facilities. This mainly regards the fields of aerothermodynamics, propulsion and structural mechanics. Since the early 1980s, when airbreathing hypersonic flight became an interesting topic, disciplinary and multidisciplinary computation and optimization made marvelous developments. The second “mathematization wave” did happen. That was due to the enormous developments of computer power and storage and to the same degree due to the very impressive progress in the field of numerical algorithms. Experimental simulation with its opto-electronic measurement techniques also flourished thanks to the computer power and storage capabilities, which became available. Computational flow simulation allows to treat steady and unsteady flow fields past and through configurations of all kinds, including surface radiation cooling—which is the permitting factor of hypersonic flight from the structural side—and thermochemical phenomena. Movable surfaces as well as aerothermoelastic deformations can be handled, and in particular also heat-transfer phenomena, both by conduction and radiation.