The U.S. Navy has developed an important ASW capability using impulsive sources to provide broadband spectral illumination for submarine detection. Present sonobuoy sources use high explosives to achieve the required source levels. Explosives present serious safety hazards and subsequently incur significant operational and manufacturing costs. Additionally, explosives produce inherently short (<100 micro-second) high intensity pulses, which are not efficient for creating low frequency acoustic energy. Advanced Power Technologies, Inc. (APTI) proposes to develop a non-explosive source by electrically initiating combustion of aluminum with water to create a long (milli-seconds) high-energy acoustic pulse. The aluminum/water reaction is highly energetic (15 kj/g aluminum) and affords the opportunity to use surrounding seawater as the oxidizer such that the energy output exceeds present explosive driven buoy systems. APTI has significant experience combusting aluminum and water and has demonstrated this combustion technique using solid aluminum wire, water, and battery to generate pressures in excess of 50 kpsi to accelerate projectiles.
Benefits: The immediate benefit of this program is to provide the Navy with a substantially safer and less expensive inventory of anti-submarine warfare sono-buoys. Present systems contain high-explosives that require special handling and care to both manufacture and deploy. The proposed concept will eliminate those explosives and lower overall lifecycle costs by eliminating the need to handle explosive materials. Commercially, an immediate market for several thousand buoys exists to upgrade and replace the present systems both in the US and abroad. The long term benefit of this program is to eliminate the use of highly toxic and expensive underwater propellants with a safe environmentally friendly energy source for underwater vehicles, both commercial and defense related. Developing the proposed impulsive source is the first step leading to steady state combustion of aluminum and seawater. The commercial potential for an efficient, safe, underwater energy source is tremendous.
Keywords: impulse, broadband, acoustic, sonobuoy, aluminum-water, electro-thermal, non-explosive, anti-submarine warfare
