| Objective: ||Develop a logistic fuels microburner in the range of 0.5 to 15kW thermal energy for application in deployed energy systems.
|| Description: ||An innovative micro-burner capable using diverse fuel sources, including JP-8 is needed. A well-atomized fuel and an air/fuel mixing device will be essential to ensure a stable flame front while maintaining a reasonable turn down ratio; proper atomization of the liquid fuel will be necessary to ensure higher efficiencies, rapid startup times, and long-term stability of the burner.
There are several atomization technologies currently used, including orifice (simple, dual, swirl, pulse-width modulated, etc.), poppet-type, and ultrasonic. The orifice type injectors are the most widely used, producing large droplets at 1000 psi. Ultrasonic injectors use low ultrasonic vibrating energy to atomize a thin film of fluid. Although they operate with low supply pressure, they are costly and do not work well with viscous fluids. None of the available technologies, though, can atomize jet fuels to produce micron-size droplets with little pressure, power, and cost.
For a micro-burner that can produce 0.5 to 15kW of thermal energy, current fuel atomization is even more difficult because the flow rate required is so slow. Recent research shows that instantaneous and complete combustion may require droplets with Sauter-mean diameters as small as 10 µm. Thus, it is necessary to design an atomizer that can produce droplets less than 10 µm. Ink/bubble-jet print heads have the ability to deliver precisely metered, extremely small particles of fluid. High definition printers deliver 2400 dots of ink per inch or higher, which is equivalent to a 10 µm droplet diameter or less. The question this effort will answer is what materials and design requirements are necessary for this same technology to produce continuous, precisely metered, and extremely fine fuel mist.
|| ||PHASE I: Design, and test a viable unit to demonstrate the feasibility of the selected concept and identify technical areas for further investigation.
|| || ||PHASE II: Design, build, and test a prototype burner unit. Evaluate performance and make necessary modification to achieve high performance design. The prototype unit will be a deliverable of the Phase II program.
|| ||DUAL USE COMMERCIALIZATION: Military application: A successful development of the microburner will have a multiple commercial applications in addition to the Air Force deployable fuel cell power generator program. Commercial application: A successful development of a compact and efficient JP-8/diesel microburner will have a multitude of commercial applications in addition to deployable fuel cell generator.
|| References: ||1. A. Nishimura1 and D. N. Assanis, “A Model for Primary Diesel Fuel Atomization Based on Cavitation Bubble Collapse Energy,” I CLASS 2000,Pasadena,CA, July 16-20, 2000.
2. Robert S. Babington, “Liquid Delivery Apparatus & Method for Liquid Fuel Burners and Liquid Atomizers,” US Patent # 4,573,904, March 1986.
3. Mitchell, Nathan and Freiman, Joseph,” Portable fuel-cell-powered system with ultrasonic atomization of H2O by-product,” US Patent # 6,259,971 B1, July 2001.
|Keywords: ||logistic fuels, fuel atomizer, fuel droplet, sauter mean diameter, native velocity, intrinsic heat dissipation|