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M E Rosalik - One of the best experts on this subject based on the ideXlab platform.
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local fuel concentration ignition and combustion in a stratified charge Spark combustion in a stratified charge Spark ignited direct injection engine spectroscopic imaging and pressure based measurements
International Journal of Engine Research, 2003Co-Authors: Todd D Fansler, Boris D Stojkovic, Michael C Drake, M E RosalikAbstract:AbstractA recently developed Spark emission spec-troscopy technique has been used to measure the effects of fuel injection timing, Spark timing and intake swirl level on the individual-cycle fuel concentration at the Spark Gap in a wall-guided Spark ignited direct injection (SIDI) engine. The fuel-concentration measurements were made simultaneously with measurements of individual-cycle Spark discharge energy and cylinder pressure. Endoscopic imaging of the fuel spray and high-speed imaging of combustion (both broadband and spectrally resolved) augment these quantitative data. For optimum engine operation, the fuel-air equivalence ratio at the Spark Gap just after Spark breakdown is rich on average (〈φ〉 ≈1.4–1.5) and varies widely from cycle to cycle (∼25 per cent). The evolution with crank angle of the mean equivalence ratio and its cycle-to-cycle fluctuations are correlated with the cylinder pressure, heat release and imaging data to provide insights into fuel transport and mixture preparation that are i...
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local fuel concentration ignition and combustion in a stratified charge Spark combustion in a stratified charge Spark ignited direct injection engine spectroscopic imaging and pressure based measurements
International Journal of Engine Research, 2003Co-Authors: Todd D Fansler, Boris D Stojkovic, Michael C Drake, M E RosalikAbstract:AbstractA recently developed Spark emission spec-troscopy technique has been used to measure the effects of fuel injection timing, Spark timing and intake swirl level on the individual-cycle fuel concentration at the Spark Gap in a wall-guided Spark ignited direct injection (SIDI) engine. The fuel-concentration measurements were made simultaneously with measurements of individual-cycle Spark discharge energy and cylinder pressure. Endoscopic imaging of the fuel spray and high-speed imaging of combustion (both broadband and spectrally resolved) augment these quantitative data. For optimum engine operation, the fuel-air equivalence ratio at the Spark Gap just after Spark breakdown is rich on average (〈φ〉 ≈1.4–1.5) and varies widely from cycle to cycle (∼25 per cent). The evolution with crank angle of the mean equivalence ratio and its cycle-to-cycle fluctuations are correlated with the cylinder pressure, heat release and imaging data to provide insights into fuel transport and mixture preparation that are i...
Shih Yao Huang - One of the best experts on this subject based on the ideXlab platform.
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effects of electrode Spark Gap differential diffusion and turbulent dissipation on two distinct phenomena turbulent facilitated ignition versus minimum ignition energy transition
Combustion and Flame, 2019Co-Authors: S S Shy, Minh Tie Nguye, Shih Yao HuangAbstract:Abstract This paper reports laminar and turbulent minimum ignition energies (MIEL and MIET) of hydrogen/air mixtures at two equivalence ratios (ϕ = 0.18 and 5.1) where Lewis numbers Le ≈ 0.3 and 2.3, respectively, over wide ranges of the electrode Spark Gap (dGap = 0.3–6.5 mm) and the r.m.s. turbulent fluctuating velocity (u′ = 0–8.3 m/s). Depending on the coupling effects of Le, dGap, and u′, we explain what causes two distinct phenomena: Turbulent Facilitated Ignition (TFI) meaning MIEL >> MIET and MIE Transition meaning a change from MIET ≥ MIEL to MIET >> MIEL when u′ is greater than some critical value. High-speed Schlieren imaging shows that the embryonic Spark kernel in quiescence is ball (rod) like when dGap 1 mm), demonstrating large (very small or negligible) positive curvature. This explains why TFI, an unusual phenomenon, only occurs at sufficiently small dGap > 1 because large positive curvature stretch weakens reaction rate due to differential diffusion, making successful ignition in quiescence very difficult to achieve. At dGap = 0.58 mm and Le ≈ 2.3, a non-monotonic decrease and increase of MIET with increasing u′ is observed, because the dissipation of ignition kernel by sufficiently intense turbulence re-declares its dominance leading to the increase of MIET. There is no TFI when dGap > 1 mm regardless of Le. The scenario changes to MIE transition when dGap = 2 mm at Le ≈ 2.3, where MIEL
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is turbulent facilitated ignition through differential diffusion independent of Spark Gap
Combustion and Flame, 2017Co-Authors: Minh Tien Nguyen, Shih Yao HuangAbstract:Abstract In 2014, Wu et al. discovered an unexpected result. Turbulence can facilitate ignition through differential diffusion when the effective Lewis number (Le) of mixtures is sufficiently larger than unity using small electrode Gaps (dGap ≤ 0.8 mm) in near-isotropic turbulence generated by a fan-stirred burner. This suggested that the required minimum ignition energy (MIE) in intense turbulence can be smaller than that in quiescence (Wu et al. did not measure MIE). This work explores whether the aforesaid turbulent facilitated ignition (TFI) for Le > 1 is independent of dGap. We apply the same hydrogen mixtures at the equivalence ratio ϕ = 5.1 (Le ≈ 2.3) and ϕ = 0.18 (Le ≈ 0.3) as Wu et al. in our large fan-stirred cruciform bomb capable of generating near-isotropic turbulence to measure values of MIE as a function of dGap at both quiescence and intense turbulence (the rms turbulent fluctuating velocity u′ = 5.4 m/s) conditions. A drastic fall of values of laminar and turbulent MIE (MIEL and MIET) with increasing dGap is observed. TFI only occurs for Le > 1 (ϕ = 5.1) and it is restricted at smaller dGap = 0.58 mm, where MIEL = 61.5 mJ >> MIET = 26 mJ (0.25-mm tungsten electrodes) and MIEL = 255.5 mJ >> MIET = 36.8 mJ (2-mm tungsten electrodes) in support of Wu et al.’s finding. However, we discover that the MIEL and MIET curves versus dGap can cross each other at larger dGap, at which no TFI for Le > 1 at dGap = 2 mm where MIEL = 0.52 mJ
Ajm Guus Pemen - One of the best experts on this subject based on the ideXlab platform.
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novel multiple switch blumlein generator
Review of Scientific Instruments, 2006Co-Authors: Zhen Liu, K Yan, Gjj Hans Winands, Van Ejm Bert Heesch, Ajm Guus PemenAbstract:The Blumlein generator has been one of the most popular pulsed-power circuits. The pulse forming lines are charged simultaneously, and then discharged via a single switch, such as a Spark Gap. The generator can be used for single pulse or at a high repletion rate. However, for large pulsed power generation, one critical issue for such a single-switch based circuit topology is related to large switching currents. In this article, we propose a novel Blumlein circuit topology based on multiple switches. The pulsed forming lines are charged in parallel and then are synchronously commutated via multiple switches. No special synchronization trigger circuit is needed for the proposed circuit topology; this robust circuit topology is simple and very reliable. A prototype multiple-switch Blumlein generator with two Spark-Gap switches has been experimentally evaluated with both resistive and corona plasma loads. In terms of the switching currents, it is observed that the two switches can be synchronized within 2–3 ns. The energy conversion efficiencies are 82% and 76.8% for a matched resistive load and a plasma reactor, respectively.
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a triggered Spark Gap switch for high repetition rate high voltage pulse generation
Journal of Electrostatics, 2003Co-Authors: Keping Yan, Van Ejm Bert Heesch, S A Nair, Ajm Guus PemenAbstract:Abstract A triggered Spark-Gap switch together with a LCR trigger circuit has been developed in order to produce high levels of pulsed corona plasma at high-repetition rate and with a long lifetime. The Spark-Gap switch is flushed in air with a gas flow rate of up to 100 m 3 /h. Experiments are carried out up to 10 kW average output power, 12 J/pulse, and 900 pps (pulses per second).
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a triggered Spark Gap switch for high repetition rate high voltage pulse generation
Journal of Electrostatics, 2003Co-Authors: Van Ejm Bert Heesch, S A Nair, Ajm Guus PemenAbstract:Abstract A triggered Spark-Gap switch together with a LCR trigger circuit has been developed in order to produce high levels of pulsed corona plasma at high-repetition rate and with a long lifetime. The Spark-Gap switch is flushed in air with a gas flow rate of up to 100 m 3 /h. Experiments are carried out up to 10 kW average output power, 12 J/pulse, and 900 pps (pulses per second).
Pikaloka, Teguh Vio - One of the best experts on this subject based on the ideXlab platform.
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DESAIN RANGKAIAN PELIPAT TEGANGAN 6 kV MARX GENERATOR EMPAT TINGKAT SEBAGAI CATU TEGANGAN GENERATOR SURJA
Jurnal Mahasiswa TEUB, 2018Co-Authors: Pikaloka, Teguh Vio, Wijono N/aAbstract:Marx Generator, salah satu jenis rangkaian pelipat tegangan yang terdiri dari resistor, kapasitor dan Spark Gap. Rangkaian ini mampu menghasilkan tegangan output berbentuk impuls dengan nilai yang lebih besar dari tegangan input DC. Memiliki dimensi yang kecil dan portable, komponen yang mudah ditemui di pasaran, serta biaya yang murah menjadi poin utama pada Marx Generator. Rangkaian Marx Generator dirancang dan dibuat untuk mengisi storage capacitor pada peralatan pembangkit kombinasi tegangan-arus impuls atau yang biasa disebut dengan generator surja dengan mengikuti standar yang ditetapkan oleh IEC (International Electrotecnical Commission) 61000-4-5 kelas 4. Marx Generator dirancang hingga mampu membangkitkan tegangan 6 kV dengan menggunakan kapasitor high voltage 100nF/3kV yang diparalel dengan resistor 10kΩ/5 Watt dan kemudian disusun menjadi empat tingkat, dimana pada setiap tingkatnya terdapat sebuah Spark Gap berupa baut dengan diameter 5mm dan panjang 6cm. Pengambilan data pada penelitian ini dilakukan saat rangkaian Marx Generator dalam kondisi tanpa beban dan berbeban. Dalam pengujiannya, dibuat variasi jarak pada sela Spark Gap yaitu 0,2 mm, 0,5 mm, 1 mm, 1,5 mm dan 2 mm. Hasil pengujian tanpa beban pada ruangan dengan keadaan udara sembarang, diperoleh nilai output tegangan impuls maksimal yaitu 6,8 kV dimana ketika jarak sela dinaikkan, maka nilai V input yang dibutukan untuk menghasilkan Spark pada sela juga semakin besar. Sedangkan, saat kondisi berbeban Marx Generator mampu mengisi storage capacitor hingga tegangan 3,7 kV dalam waktu 98 menit. Kata Kunci: Pelipat Tegangan Marx Generator, Spark Gap, Tegangan Storage capacitor. ABSTRACT Marx Generator, one kind of voltage multiplier circuit consist of resistors, capacitors and Spark Gaps. This circuit produces an impulse output voltage with a value greater than the DC input voltage. Has a small dimension and portable, easy to find components, and low cost become the main points on Marx Generator. The Marx Generator circuit is designed and manufactured to fill storage capacitors in impulse current voltage generating devices or so-called surge generators in accordance with the standards set by IEC (International Electrotecnical Commission) 61000-4-5 class 4. Our Marx Generator is designed to be able to generate 6 kV voltage by using 100nF / 3kV high voltage capacitor paralleled with 10kΩ / 5Watt resistor and then arranged into four levels, where each level there is a Spark Gap of bolts with diameter 5mm and lengths 6cm in each level. In this research the data is collected when Marx Generator works with and without load condition. On the test, the variations distance between the Spark Gap are 0.2 mm, 0.5 mm, 1 mm, 1.5 mm and 2 mm. Based on no-load test in room with any air condition, we obtained the value of maximum output impulse voltage at 6.8 kV when the distance is increased, then the value of V input become greater to produce Spark in a Gap. Meanwhile, when it comes with load condition Marx Generator able to fill storage capacitor up to 3,7 kV voltage within 98 minutes. Keywords: Marx Generator Voltage Multiplier, Spark Gap, Storage capacitor Voltage
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Desain Rangkaian Pelipat Tegangan 6 kV Marx Generator Empat Tingkat sebagai Catu Tegangan Generator Surja
2018Co-Authors: Pikaloka, Teguh VioAbstract:Marx Generator adalah salah satu jenis rangkaian pelipat tegangan yang terdiri dari resistor, kapasitor dan Spark Gap. Rangkaian ini mampu menghasilkan tegangan output berbentuk impuls dengan nilai yang lebih besar dari tegangan input DC. Memiliki dimensi yang kecil dan portable, komponen yang mudah ditemui di pasaran, serta biaya yang murah menjadi poin utama pada Marx Generator. Pada penelitian ini rangkaian Marx Generator dirancang dan dibuat untuk mengisi storage capacitor pada peralatan pembangkit kombinasi tegangan-arus impuls atau yang biasa disebut dengan generator surja dengan mengikuti standar yang ditetapkan oleh IEC (International Electrotecnical Commission) 61000-4-5 kelas 4. Marx Generator tersebut dirancang mampu membangkitkan tegangan hingga 6 kV. Generator dibangun menggunakan kapasitor high voltage 100nF/3kV yang diparalel dengan resistor 10kΩ/5 Watt dan kemudian disusun menjadi empat tingkat, dimana pada setiap tingkatnya dipasang sebuah Spark Gap berupa baut dengan diameter 5mm dan panjang 6cm. Pengambilan data pada penelitian ini dilakukan saat rangkaian Marx Generator dalam kondisi tanpa beban dan berbeban. Dalam pengujiannya, dibuat variasi jarak pada sela Spark Gap yaitu 0,2 mm, 0,5 mm, 1 mm, 1,5 mm dan 2 mm. Hasil pengujian tanpa beban pada ruangan dengan keadaan udara sembarang, menunjukkan nilai output tegangan impuls maksimal yaitu 6,8 kV. Ketika jarak sela dinaikkan, maka nilai tegangan input yang dibutukan untuk menghasilkan Spark pertama kali pada sela juga semakin besar. Saat kondisi berbeban Marx Generator mampu mengisi storage capacitor hingga tegangan 3,7 kV dalam waktu 98 menit
Todd D Fansler - One of the best experts on this subject based on the ideXlab platform.
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local fuel concentration ignition and combustion in a stratified charge Spark combustion in a stratified charge Spark ignited direct injection engine spectroscopic imaging and pressure based measurements
International Journal of Engine Research, 2003Co-Authors: Todd D Fansler, Boris D Stojkovic, Michael C Drake, M E RosalikAbstract:AbstractA recently developed Spark emission spec-troscopy technique has been used to measure the effects of fuel injection timing, Spark timing and intake swirl level on the individual-cycle fuel concentration at the Spark Gap in a wall-guided Spark ignited direct injection (SIDI) engine. The fuel-concentration measurements were made simultaneously with measurements of individual-cycle Spark discharge energy and cylinder pressure. Endoscopic imaging of the fuel spray and high-speed imaging of combustion (both broadband and spectrally resolved) augment these quantitative data. For optimum engine operation, the fuel-air equivalence ratio at the Spark Gap just after Spark breakdown is rich on average (〈φ〉 ≈1.4–1.5) and varies widely from cycle to cycle (∼25 per cent). The evolution with crank angle of the mean equivalence ratio and its cycle-to-cycle fluctuations are correlated with the cylinder pressure, heat release and imaging data to provide insights into fuel transport and mixture preparation that are i...
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local fuel concentration ignition and combustion in a stratified charge Spark combustion in a stratified charge Spark ignited direct injection engine spectroscopic imaging and pressure based measurements
International Journal of Engine Research, 2003Co-Authors: Todd D Fansler, Boris D Stojkovic, Michael C Drake, M E RosalikAbstract:AbstractA recently developed Spark emission spec-troscopy technique has been used to measure the effects of fuel injection timing, Spark timing and intake swirl level on the individual-cycle fuel concentration at the Spark Gap in a wall-guided Spark ignited direct injection (SIDI) engine. The fuel-concentration measurements were made simultaneously with measurements of individual-cycle Spark discharge energy and cylinder pressure. Endoscopic imaging of the fuel spray and high-speed imaging of combustion (both broadband and spectrally resolved) augment these quantitative data. For optimum engine operation, the fuel-air equivalence ratio at the Spark Gap just after Spark breakdown is rich on average (〈φ〉 ≈1.4–1.5) and varies widely from cycle to cycle (∼25 per cent). The evolution with crank angle of the mean equivalence ratio and its cycle-to-cycle fluctuations are correlated with the cylinder pressure, heat release and imaging data to provide insights into fuel transport and mixture preparation that are i...
