• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.63-64
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• 2012

The present study has numerically investigated the effects of the fuel-side nitrogen dilution on the precise structure and NOx formation characteristics of the turbulent syngas nonpremixed flames. Numerical results indicate that for highly diluted case, the flame structure is dominantly influenced by the turbulence-chemistry interaction and marginally modified by the radiation effect. On the other hand, no-dilution case with the longer flight time and the relatively intermediate scalar dissipation rate is influenced strongly by the radiative cooling as well as moderately by the turbulence-chemistry interaction.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.19-22
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• 2012

Experimental study in coflow jet flames has been conducted to investigate effects of adding Helium to coflowing air-side in self-excitation. The Differences between buoyancy-driven and diffusive-thermal self-excitations with the same order of O(1.0 Hz) in self-excitation are explored and discussed in laminar coflow jet flames.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.267-268
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• 2012

Soot formation and oxidation characteristics of air-diluted propane diffusion flames have been experimentally investigated under the elevated pressure conditions. PAH concentrations showed more pressure sensitive behavior comparing to soot volume fractions. The flame/soot temperatures in soot oxidation region were obtained using the MOLLIP technique. Under the complete soot oxidation environment, the flame/soot temperature is increased with pressure. The increased temperature could accelerate the soot oxidation process and then exothermic oxidation reaction, in turn, could further raise the flame/soot temperature, which would result in the enhancement of soot oxidation process.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.934-941
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• 2011

Characteristics of low NOx burner is investigated. Low NOx burner introduced in this paper adopts two staged combustion with plasma burner for the 1st stage combustion. Extensive parametric tests were done to figure out the effect of burner stoichiometry, staged thermal load, electric power for plasma generation. Overall NOx production by burner shows effective reduction by adopting plasma staged burner. and the aspects depends on the fuel stoichiometry of 1st stage burner or operating condition of plasma burner. It is promising to use plasma burner as an alternative tools of low NOx burner technology.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2000.05a
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• pp.259-260
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• 2000

충남 지역에서 발생되는 하수 슬러지의 물리$\cdot$화학적 특성을 고려하여 적정 처분 방안을 검토하기 위하여 중금속 및 비휘발성 고형물 분석을 수행하였다. 충남 지역에서 발생되는 하수 슬러지의 중금속 함유량은 기준치 이하로서 다소 안전하다 할 수 있으나 지속적인 관리가 요구되며, 이러한 중금속의 함유량도 타폐기물과의 혼합으로 희석효과를 가질 수 있을 것으로 사료된다. 또, 하수 슬러지의 광물 낙석 결과 하수 슬러지의 비휘발성 고형분의 성분은 시멘트 원료로 쓰이는 점토질과 유사하며 소각후에 연소재를 이용한 경량 골재 및 다른 2차 제품의 제조 가능성이 높은 것으로 판단된다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.525-531
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• 2011

Exhaust gas recirculation (EGR) is more effective than selective catalytic reduction (SCR) or lean $NO_x$ trap (LNT) for the reduction of $NO_x$ emissions in diesel engines. A large amount of EGR gas is necessary to satisfy the stringent regulations on $NO_x$ emissions. Low pressure loop (LPL) EGR is almost independent of the variable geometry turbocharger (VGT) at a specific boost pressure, so LPL EGR is better than conventional high pressure loop (HPL) EGR in terms of EGR supply. We compare the influence of HPL EGR and LPL EGR on the combustion characteristics at a constant boost pressure in a diesel engine. The dilution ratio was employed as an independent parameter to analyze the effect of the dilution of the intake charge for each EGR loop. At the same level of $NO_x$ emissions, the fuel consumption and smoke opacity were slightly lower for LPL EGR than for HPL EGR.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.259-264
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• 1993

Ion chromatographic method has been applied for burnup measurement of irradiated nuclear fuel by dynamic system using 1-octanesulfonate as a cation exchanger and $\alpha$-hydroxyisobutyric acid as an eluant. A number of elution techniques were evaluated for the optimum separation of plutonium, uranium and neodymium. These elements were individually separated and collected by gradient elution between 0.05 M and 0.40 M of $\alpha$-hydroxyisobutyric acid in a single column, and finally determined by isotope dilution mass spectrometry. The burnup data from this method were compared with those from conventional anion exchange method. The results showed a good agreement within 3.5 % of difference between two methods.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.155-160
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• 2001

The low NOx characteristics have been investigated to develop the combustor for micro turbine. The lean premixed combustion technology was applied to reduce the NOx emission. The test was conducted at the condition of high temperature and ambient pressure. The combustion air which has the temperature of $450\sim650K$ were supplied to the combustor through the air preheater. The temperature and emissions of NOx and CO were measured at the exit of combustor, The exit temperature and NOx were increased and CO was decreased with increasing inlet air temperature. The premixing chamber can be operated very lean condition of equivalence ratio around 0.35. The NOx was decreased with decreasing the equivalence ratio. The CO was decreased with decreasing the equivalence ratio, but the CO was increased with decreasing the equivalence ratio below 0.4. But, at the very lean condition of equivalence ratio below 0.35 both NOx and CO were increased because of the flame unstability. The NOx was decreased and CO was increased with increasing inlet air flowrate. This results can be used to determine the size of combustor. Consequently the performance of combustor shows the possibility of the application to the gas turbine system.

• Journal of ILASS-Korea
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• v.3 no.1
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• pp.19-26
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• 1998

The effect of mixture component makes a nelay time and a long total combustion period $\tau_{p\;max}$. The flame propagation delay $\tau_{df}$ was determined by the record of current ion. The pressure release delay $\tau_{dp}$ and $\tau_{p\;max}$ were determined by the indicated pressure diagram in constant volume of the combustion chamber. The results are as follows: 1) The ignition delay $\tau_t$ time takes the minimum value around $\Phi=1.15$. 2) $\tau_{df}$ and $\tau_t$ time increased according to the increases of the concentrated dilution gases, because the adiabatic flame temperature decreased due to the increases of the heat capacity. But dilution gases have little effect on flame nucleus formation delay 3) The relation between $\tau_t$ time and reciprocal laminar burning velocity is almost linear. 4) The increase of the propagation length is accompanied with increased ratio of the $\tau_{df},\;\tau_{dp},\;\tau_{t},\;\tau_{p\;max}$.

• Analytical Science and Technology
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• v.16 no.3
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• pp.191-197
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• 2003

Two methods, IDMS (Isotope Dilution Mass Spectrometry) and controlled potential coulometry are compared by the determination of Pu for the NBL, CRM No.122, $PuO_2$. The recovery of Pu was found to be $1.002176{\pm}0.000452$ within the relative standard deviation of 0.045% (95% conf. level) although a small size of sample ($0.9{\mu}g$-Pu) was used in IDMS. The recovery using controlled potential coulometry were obtained in the range of 0.9923~0.9960. The analytical results of IDMS and controlled potential coulometry were good agreement within 0.6~1%. Base on these experiment results, The plutonium in HANARO irradiated fuel rod that separated portion of top, middle, and bottom were determined. The measured values of Pu are 1.155 mg, 2.483 mg and 1.920 mg in one gram of sample(fuel+clad), respectively.