Autoignition And Burning Speeds Of Jp 8 Fuel At High Temperatures And Pressures

MIL-T-83133C grade JP-8 is of interest to the U.S. Army as the single fuel for the battlefield. The conversion to JP-8 occurred primarily to improve the safety of aircraft, although the single fuel for the battlefield concept (and the similarity of jet fuel to diesel fuel) is centered on the use of aviation kerosene in all Air Force and Army aircraft and ground vehicles. Detailed chemical kinetic mechanisms that describe combustion of many of the components in JP-8 are not available and are unlikely to be developed in the near future. Hence there is a need to study the characteristics of JP-8 experimentally. The following is the final progress report on our developments and accomplishments through May 2001- May 2004. The detail of the experimental facilities including two combustion chambers, spherical and cylindrical, optical set up, a high temperature oven and also our thermodynamic model used to calculate burning speed were discussed in the last reports and will be briefly discussed here. Measurements have been done in these facilities for gaseous and liquid fuels over the wide range of temperature and pressure. In the last year we developed a new heating system for fuel injection line in cylindrical vessel. The liquid fuel line in the spherical vessel was redesigned. Burning speeds of premixed JP-8 air have been measured for a range of temperature and pressure. Pictures of JP-8 flame have been taken using the high speed CCD camera in the cylindrical chamber. The results are presented in this report.

The capabilities of the combustion laboratory at Northeastern University have increased tremendously over the past year. The construction of the new experimental apparatus has allowed for much greater productivity. The addition of thick windows for the cylindrical vessel has allowed the lab to undertake testing at higher pressures and temperatures. Follow up the previous reports; we have used our modified burning model to measure laminar burning speed of JP-8, 21% O2 and 79% He at wide range of temperature, pressure and equivalence ratio.

This book presents a step-by-step methodology for the design of ramjet engines. It explores ramjet combustion, provides guidelines on how to size the engines, and discusses performance analysis. The book begins with an introduction to ramjet design, including fundamental definitions in the field. It then discusses ramjet engine performance, and fuels which can be used. Several types of ramjet engines are then explored, and guidelines for their design are presented, including flame holders, injectors, and combustors. Finally, the book concludes with a discussion of the types of materials which should be used for ramjet engines. This book is of interest to engine designers and engineers, researchers, and graduate students, as it collates research in a succinct, clear guide to the issue of designing ramjet engines.

Laminar burning speed is a thermophysical property of a combustible mixture. It is a measure of the rate of energy released during combustion in quiescent gas mixtures and incorporates the effects of overall reaction rates, energy (heat) of combustion and energy and mass transport rates. There are several experimental techniques to measure laminar burning speed and they can be broadly categorized into two general categories of stationary flames methods and those that are based on propagating flames. Investigation of spherical flame propagation in constant volume vessels is recognized to be one of the most accurate approaches for laminar burning speed measurement and flame structure study. In this thesis flame structure, laminar burning speed and onset of autoignition are studied for different premixed combustible mixtures including n-decane, jet-fuels, and Hydrofluorocarbon (HFC) refrigerants in air at high temperatures and pressures over a wide range of fuel-air equivalence ratios. The experimental facilities consist of two spherical and cylindrical vessels. The spherical vessel is used to collect pressure data to measure the burning speed and cylindrical vessel is used to take pictures of flame propagation with a high speed CMOS camera located in a shadowgraph system. A thermodynamic model is employed that assumes unburned gases compress isentropically and that burned gases are in local thermodynamic equilibrium. Burning speed is derived from the time rate change of mass fraction of burned gases. The major advantages of this method are that it circumvents the need for any extrapolation due to having low stretch rates and that many data points can be collected along an isentrope in a single experiment. Flame structures are studied to determine the cell formation conditions. Critical pressures at which the flame becomes cellular are identified and the effects of important parameters on cell formation are studied. Autoignition experiments are carried out for JP-8 fuels with high initial pressures in the spherical chamber. Autoignition occurs at specific temperature and pressure during the compression of unburned gas due to flame propagation.

This book deals with novel advanced engine combustion technologies having potential of high fuel conversion efficiency along with ultralow NOx and particulate matter (PM) emissions. It offers insight into advanced combustion modes for efficient utilization of gasoline like fuels. Fundamentals of various advanced low temperature combustion (LTC) systems such as HCCI, PCCI, PPC and RCCI engines and their fuel quality requirements are also discussed. Detailed performance, combustion and emissions characteristics of futuristic engine technologies such as PPC and RCCI employing conventional as well as alternative fuels are analyzed and discussed. Special emphasis is placed on soot particle number emission characterization, high load limiting constraints, and fuel effects on combustion characteristics in LTC engines. For closed loop combustion control of LTC engines, sensors, actuators and control strategies are also discussed. The book should prove useful to a broad audience, including graduate students, researchers, and professionals Offers novel technologies for improved and efficient utilization of gasoline like fuels; Deals with most advanced and futuristic engine combustion modes such as PPC and RCCI; Comprehensible presentation of the performance, combustion and emissions characteristics of low temperature combustion (LTC) engines; Deals with closed loop combustion control of advanced LTC engines; State-of-the-art technology book that concisely summarizes the recent advancements in LTC technology. .