Browsing by Subject "Jet Ignition"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Experimental investigation on traversing hot jet ignition of lean hydrocarbon-air mixtures in a constant volume combustor
    (2013-12) Chinnathambi, Prasanna; Nalim, M. Razi; Yu, Huidan (Whitney); Zhu, Likun; Anwar, Sohel
    A constant-volume combustor is used to investigate the ignition initiated by a traversing jet of reactive hot gas, in support of combustion engine applications that include novel wave-rotor constant-volume combustion gas turbines and pre-chamber IC engines. The hot-jet ignition constant-volume combustor rig at the Combustion and Propulsion Research Laboratory at the Purdue School of Engineering and Technology at Indiana University-Purdue University Indianapolis (IUPUI) was used for this study. Lean premixed combustible mixture in a rectangular cuboid constant-volume combustor is ignited by a hot-jet traversing at different fixed speeds. The hot jet is issued via a converging nozzle from a cylindrical pre-chamber where partially combusted products of combustion are produced by spark- igniting a rich ethylene-air mixture. The main constant-volume combustor (CVC) chamber uses methane-air, hydrogen-methane-air and ethylene-air mixtures in the lean equivalence ratio range of 0.8 to 0.4. Ignition delay times and ignitability of these combustible mixtures as affected by jet traverse speed, equivalence ratio, and fuel type are investigated in this study.
  • Thumbnail Image
    Item
    Jet Ignition for Super-Efficient Power Generation and Propulsion
    (Office of the Vice Chancellor for Research, 2012-04-13) Nalim, M. Razi
    Jet Ignition for Super-Efficient Power Generation and Propulsion Global environmental concerns and energy price hikes compel more efficient transport and power generation with disruptively different technologies. Wave rotor technology developed at IUPUI employs new combustion and ignition processes that develop high pressure and increased power resulting in enormous energy and cost savings. The wave rotor combustor (WRC) uses pressure wave compression and confined combustion in multiple rotating chambers. For ignition, partially combusted gas in a transient jet from a pre-chamber penetrates and ignites the main chamber lean mixture, over multiple ignition points. This intense ignition overcomes mixture non-uniformity and improves efficiency and emission. Chemically active radicals and fast turbulent mixing in the jets create an explosion two orders more energetic than a spark. Jet ignition offer the advantage of fast ignition and rapid complete combustion of leaner and stratified mixtures, mitigate heat losses to the walls and minimize pollutant emissions, while enabling higher engine efficiency.
  • Thumbnail Image
    Item
    Jet Ignition Research for Clean Efficient Combustion Engines
    (Office of the Vice Chancellor for Research, 2013-04-05) Chinnathambi, Prasanna; Karimi, Abdullah; Rajagopal, Manikanda; Nalim, M. Razi
    Ignition by a jet of hot gas has application in lean-burn pre-chamber internal combustion engines and in innovative pressure-gain combustors for gas turbine engines. Jet ignition offers the advantage of reliable fast ignition and complete combustion of leaner mixtures. Fast burn rates due to the energetic ignition source produce multiple, distributed ignition zones, which consume the fuel-air mixture rapidly. Chemically active radicals and fast turbulent mixing in the jets create an explosion much more energetic than a spark. This high energy ignition results from the partially combusted gas from the pre-chamber products initiating combustion in the main chamber mixture. IC engines using low-cost, low-carbon natural gas need improved methods for ignition of lean mixtures to avoid nitrogen oxide emissions. This usually requires a richer mixture in the pre-chamber which is spark-ignited using a little additional gas fuel or compression-ignited with diesel fuel, possibly with a glow plug. A jet of hot reactive gas then ignites the main chamber lean mixture. Novel approaches for gas turbine engines using constant-volume, pressure-gain combustion include the multi-chamber wave rotor combustor. A wave rotor combustion chamber is best ignited with a jet of hot gas that may come from a small separately fueled pre-chamber or from a previously combusted chamber. Experiments on traversing and stationary jets have been conducted using the constant-volume wave rotor combustor established at combustion and propulsion research laboratory, IUPUI. The ignitability limit and ignition delay time for various hydrocarbon fuels (methane, ethylene and propane) have been investigated. Ignition characteristics have been analyzed using the high speed camera images and pressure data. Numerical simulations have been carried out using a hybrid eddy-break-up combustion model including finite-rate chemistry and two-equation k-ω turbulence model. Numerical and experimental results showed similar trends, with the modeling results illuminate the jet ignition process.