A Spray Nozzle with Electrically Controllable Spray Characteristics

In the conduction of benchmark combustion experiments, a fuel spray nozzle that produces a steady-well-defined spray is needed. This fuel spray, of known properties, is a boundary condition for the atomization, mixing, and combustion which results throughout the combustor volume. Present spray nozzles use fluid turbulence, which is chaotic, to drive the spray formation. Because the turbulence amplitude depends on the fluid viscosity, which depends on fluid temperature, the spray from available nozzles varies if fluids of different viscosity are used or if the nozzle temperature changes during an experiment. In an earlier USAF SBIR contract, Fluid Jet Associates developed a spray nozzle that receives atomization energy from an electromechanical drive. This driver's electrical terminals provide an input to the spray process that changes spray formation independently of the fluid properties. The solution explored here for creating a standard spray is the development of a feedback system for the electromechanical sprayer that maintains spray parameters by compensating for changes in fluid viscosity or fluid mass flow. The Phase 1 effort will be concentrated on measuring the electrical to spray transfer functions from which a control scheme can be defined.