Jean-Pierre Minard

Laser-Induced Spark Ignition of Gaseous and Quiescent N-Decane–Air Mixtures

Non-resonant breakdown ignition of quiescent mixtures of n-decane vapors and air is characterized by focusing the beam of a Nd:YAG laser operating at 1064 nm within a closed vessel. Breakdown and ignition are considered following a statistical approach: percentages of ignition are determined for different fuel equivalence ratios and pressures (Φ = 0.65–2; P0 = 0.5–4 bar) at constant initial temperature T0 = 347 K. Significant influence of these parameters is reported. The domain of systematic ignition is characterized in terms of equivalence ratio and energy delivered by the laser, i.e., parameters relevant to propulsion applications. From a more fundamental point of view, absorbed energy is considered and the minimum ignition energy value equals 0.95 mJ. Effects of air chemical composition on ignition probabilities are evidenced by employing ambient or synthetic air, with argon or water vapor. This work brings useful complements to existing studies mainly focused on decane spray ignition.

METHYLE - A New Long Endurance Test Facility for Dual-Mode Ramjet Combustor Technologies

In order to provide the ground testing capabilities needed by this technology development effort, the test facility, developed by MBDA and ROXEL in their Bourges Subdray test center in the frame of PREPHA program (nineties), has been upgraded. The so created test facility, called METHYLE, was designed to allow performing long endurance test in conditions representative to actual flight up to Mach 7.5. Thanks to a modular water-cooled dual-mode ramjet combustion chamber, called SMR, METHYLE makes possible a large set of technology tests as for endothermic fuels reforming, reformed endothermic fuels burning, element of variable geometry, sealing system, fuel-cooled structure, measurement techniques, engine control system…

Low Cost Ramjet Technology for Tactical Missile Application

For a long time, Aerospatiale Matra Missiles (now a part of MBDA France) led an important effort to develop the liquid fuel ramjet technology. This effort received a first consecration with the development of the ASMP missile (Air-to-Ground Medium Range missile), which entered the French Forces in 1986 and is still operational after a mid-life upgrade. Beyond this development a lot of advanced studies were performed to improve the technology, increase the accessible flight envelope and to develop needed numerical and experimental means. Today, a large part of our research and technology development effort dedicated to the ramjet technology is focused to the missile applications. The main purpose of such a work is the reduction of development and production cost for tactical missiles. Activity is focused on two tracks : 1. reduction of the development cost by using the same airbreathing vector for different operational applications, 2. development of a modular low cost hydrocarbon fuelled ramjet with simplified fuel storage/control/injection system for small calibre tactical missiles. For the point 1, MBDA is developing a high-performance ramjet powered system, called VESTA, based on hydrocarbon fueled ramjet. This vector, which takes advantage of ASMP experience and past general studies results, will be flight tested this September 2002. It is worth noting that this development takes also advantage of the very spectacular progress obtained for numerical prediction : for example, VESTA ramjet has been developed with ten times less combustion tests than the ASMP one while the number of flight tests will be divided by four. For the point 2, several studies and advanced developments have been performed in France on the ducted rocket concept, including choked and unchoked technology. After these, MBDA focused its efforts to the development of a low cost ramjet solution for mass production tactical missiles by using a systematically simplified version of the liquid fuel ramjet concept. The RASCAL concept, developed by MBDA with a partial support of French MoD, demonstrates that it is possible to dramatically simplify the technology then to reduce the cost of the liquid fuel ramjet concept while keeping the most part of its intrinsic performances. The capability of this concept to cover all the flight envelope needed by any kind of tactical missile has been demonstrated. It has a real capability for quick and cheap adaptation to every imaginable mission (Air-to-Air, Air-to-Ground, Anti-Radiation, target, light weight antiship...). In 2000, a full demonstration of the system was obtained thanks to two synthesis ground tests, performed under the French MoD funding, during which a complete ramjet propulsion system was operated along a low altitude trajectory on one hand and a mediumhigh altitude trajectory on the other hand. Today, new combustion test are performed to assess the performance of the concept for large engine caliber while integrated booster compatibility and injectors reliability are demonstrated. These works will improve the technology readiness level of RASCAL concept, allowing to consider several possible applications for the short/middle term : supersonic target, low cost supersonic anti-ship missile, intermediate caliber antiradiation missile... ------------------------------------------------------------------------Copyright

Affordable Low Cost Liquid Ramjet Technology For Tactical Missiles

For a long time, MBDA France (former AEROSPATIALE MISSILES) led an important effort to develop the liquid fuel ramjet technology. This effort received a first consecration with the development of the ASMP missile (Air-to-Ground Medium Range missile), which entered the French Forces in 1986 and is still operational after a mid-life upgrade. Beyond this development a lot of advanced studies were performed for improving the technology, increasing the accessible flight envelope and developing needed numerical and experimental means.