SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  AF071-199 (AirForce)
Title:  Affordable Pulse-Power Module for Nonthermal Ignition and Plasma Surface Modification
Research & Technical Areas:  Air Platform, Space Platforms

  Objective:  Design, develop, and demonstrate the operation of a pulse-power module to create nonequilibrium atmospheric plasma for combustion enhancement and control.
  Description:  Recent advances in the short-pulse high-voltage sources allow for the creation of atmospheric pressure nonequilibrium plasma where the electron mean energy is much greater than neutral gas thermal energy, which can be nearly at room temperature. Atmospheric pressure nonequilibrium plasma sources have been developed for high flux photon/radical generation for a wide variety of industrial applications. (1) Short-pulse high voltage devices have been used to initiate the combustion process via the creation of reactive species/vacuum ultraviolet (VUV) photons in nonthermal plasma. The voltage pulse rise time, pulse duration, pulse energy and output impedance scaling are necessary to develop a robust pulsed high voltage system which can be used for combustion enhancement under adverse conditions, such as high altitude engine relight and/or short combustor residence time. (2) The low gas temperature of the high-pressure plasma produced by high voltage short-pulse devices will open up new plasma processing applications, such as the treating of plastics, glass, and polymers. Plasma-chemical methods suitable for coating and surface treatment can replace conventional galvanic methods, and they have the potential to be less harmful for the environment than the galvanic chemical coating process. To create these discharges, it will be necessary to develop pulse forming networks geared for each application. (3) The Air Force wishes to follow up on research on high-repetition-rate pulse systems to improve the performance and reliability of this type of device and potentially decrease the total manufacturing cost, and thereby opening up the commercial market for these devices. A pulsed-power module that can output a variable voltage (10 kV to 50 kV), a variable pulse duration (30 nsec uo to 150 nsec), and a variable pulse repetition rate (200 Hz and 3 kHz) and output impedance near 50 ohm is required. The necessary energy per pulse depends on the application. For low pressure turbine combustion, roughly 50 to 300 mJ per pulse may be required. For scramjet combustion, roughly 200 to 800 mJ per pulse may be required. Smart electronics that will detect and prevent arcing is desirable. The variables mentioned above do not need to be continuous variables; discrete component design will be acceptable.

  PHASE I: Design a pulse-power module and demonstrate the proof of concept operation of the high-voltage pulser which can be scaled up to meet the described pulser specifications.
  
  PHASE II: Develop a pulse-power module and demonstrate the scaling of the high-voltage pulse, pulse rise time, pulse duration, repetition rate, pulse energy, and output impedance. Demonstrate the hardware operation by creating atmospheric pressure nonthermal plasma for either ignition/combustion enhancement and/or plasma surface modification. Deliverables include a high-voltage pulse power hardware module.

  DUAL USE COMMERCIALIZATION: Military application: Develop prototype pulse-power modules for turbine afterburner combustion instability control, high-altitude UAV flame holding, pulse-detonation engines, and/or scramjet combustion. Commercial application: Develop prototype pulse-power modules to create nonthermal plasma for materials processing, biomedical sterilization, and/or water purification.

  References:  1. Bogaerts, A., Neyts, E., Gijbels, R., and van der Mullen, J., “Gas discharge plasmas and their applications,” <i>Spectrochemica Acta</i>, Part B, Vol. 57, pp. 609 and other references therein, 2002. 2. Bozhenkov, S.A., Starikovskaia, S.M., and Starikovskii, A.Yu., “Nanosecond gas discharge ignition of H2 and CH4 containing mixtures,” <i>Combustion and Flame</i>, Vol. 133, pp. 133, 2003. 3. Liu, K., Hu, Q., Qiu, J., and Xiao, H., “A High Repetition Rate Nanosecond Pulse Power Supply for Nonthermal Plasma Generation,” <i>IEEE Trans. Plasma Sci.</i>, Vol. 33, pp. 1182, 2005.

Keywords:  pulse-power, high-altitude jet engine relight, combustion and flame holding, high flux radical and VUV/UV photon generation, atmospheric pressure nonequilibrium plasma

Questions and Answers:
Q: 1. Pulse risetime is mentioned but no numeric requirements are listed for the pulsed power module. Are there any specific requirements or guidelines for pulse risetime, falltime, or pulse flatness?

2. Are there any specific size/weight limitations or packaging guidelines for the pulsed power module?

3. Are there any lifetime requirements or guidelines for the pulsed power module?

4. The voltage and pulse duration ranges suggest energy per pulse values from 60 mJ to 7.5 J. Since the combustion application seems to suggest pulse energies of less than 1 J, can we assume that (1 J energy per pulse) as an additional parameter space limit? Or is higher pulse energy desirable for exploring other applications or other research?
A: 1. High voltage pulse rise time is one of the most important parameter for this SBIR topic. The pulse full width half maximum (FWHM) and the pulse fall time should be such that it permits to deliver energy to the load. The exact FWHM and the pulse decay time are not critical parameters, since the load impedance may determine the FWHM and the decay time.

2. The size, weight and the packaging requirements have not specified, since low and the high end of the pulse energy system may require different size, weight and packaging requirement. For combustion applications, the size, weight and packaging would have to be compatible with the currently used jet engine ignition hardware.

3. Lifetime requirement is not explicitly specified. Low cost requirement is specified. If the design is not reliable and robust, compared to the currently used ignition module, it will not be considered as a product improvement.

4. Pulse energy up to one Joule is expected to have several potential applications for nonthermal high pressure plasma generation. Scalability to higher pulse energy is desired for a specific SCRAMJET application.
Q: 1. Pulse risetime is mentioned but no numeric requirements are listed for the pulsed power module. Are there any specific requirements or guidelines for pulse risetime, falltime, or pulse flatness?

2. Are there any specific size/weight limitations or packaging guidelines for the pulsed power module?

3. Are there any lifetime requirements or guidelines for the pulsed power module?

4. The voltage and pulse duration ranges suggest energy per pulse values from 60 mJ to 7.5 J. Since the combustion application seems to suggest pulse energies of less than 1 J, can we assume that (1 J energy per pulse) as an additional parameter space limit? Or is higher pulse energy desirable for exploring other applications or other research?
A: 1. High voltage pulse rise time is one of the most important parameter for this SBIR topic. The pulse full width half maximum (FWHM) and the pulse fall time should be such that it permits to deliver energy to the load. The exact FWHM and the pulse decay time are not critical parameters, since the load impedance may determine the FWHM and the decay time.

2. The size, weight and the packaging requirements have not specified, since low and the high end of the pulse energy system may require different size, weight and packaging requirement. For combustion applications, the size, weight and packaging would have to be compatible with the currently used jet engine ignition hardware.

3. Lifetime requirement is not explicitly specified. Low cost requirement is specified. If the design is not reliable and robust, compared to the currently used ignition module, it will not be considered as a product improvement.

4. Pulse energy up to one Joule is expected to have several potential applications for nonthermal high pressure plasma generation. Scalability to higher pulse energy is desired for a specific SCRAMJET application.

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