This report details experimentally derived operational characteristics of numerous two-dimensional planar inlet-combustor isolator configurations at a Mach number of 4. Variations in geometry included (1) inlet cowl length; (2) inlet cowl rotation angle; (3) isolator length; and (4) utilization of a rearward-facing isolator step. To obtain inlet-isolator maximum pressure-rise data relevant to ramjet-engine combustion operation, configurations were mechanically back pressured. Results demonstrated that the combined inlet-isolator maximum back-pressure capability increases as a function of isolator length and contraction ratio, and that the initiation of unstart is nearly independent of inlet cowl length, inlet cowl contraction ratio, and mass capture. Additionally, data are presented quantifying the initiation of inlet unstarts and the corresponding unstart pressure levels. Emami, Saied and Trexler, Carl A. and Auslender, Aaron H. and Weidner, John P. Langley Research Center...

The matters discussed and presented in the chapters of this book cover a wide spectrum of topics and research methods commonly used in the field of engine combustion technology and vehicle functional systems. This book contains the results of both computational analyses and experimental studies on jet and reciprocating combustion engines as well heavy-duty onroad vehicles. Special attention is devoted to research and measures toward preventing the emission of harmful exhaust components, reducing fuel consumption or using unconventional methods of engine fueling or using renewable and alternative fuels in different applications. Some technical improvements in design and control of vehicle systems are also presented.

Abstract: A numerical investigation of the flow in scramjet isolators has been conducted in an effort to determine the influence of cross-section geometry on isolator performance. Flow in axi-symmetric isolator configurations is compared with isolators having rectangular cross-section geometries. In this study, various combinations of inflow Mach number, cross-section area, and back pressure are specified as input data in the computational procedure to evaluate performance characteristics of the given isolators. The length and location of the shock train are generally regarded among key flow phenomena that influence isolator performance. This study shows that, for a range of incoming Mach numbers and different cross-section geometries, an isolator with an axi-symmetric cross- section performs better than one with a rectangular cross-section. This can be attributed largely to losses associated with corner flow in isolators having a rectangular crosssection. In general, the results of this study indicate that improvements in isolator performance are attained in isolators having axi-symmetric cross-sections and that improvements increase with increasing Mach number. The numerical results are compared with experimental data, and the agreement with the trends of the experimental data is most encouraging.

An almost entirely self-contained engineering textbook primarily for use in undergraduate and graduate courses in airbreathing propulsion. It provides a broad and basic introduction to the elements needed to work in the field as it develops and grows. Homework problems are provided for almost every individual subject. An extensive array of PC-based user-friendly computer programs is provided in order to facilitate repetitious and/or complex calculations. Annotation copyright by Book News, Inc., Portland, OR