Characteristics of Soot and Radiation of Post Combustion Simulated Gas from a Gas Generator

It is necessary to install a specific burner system to burn out fuel-rich post combustion gas produced from a gas generator in a rocket engine when the performance of gas generator is separately evaluated in a test facility. Because of the fuel-rich reburning conditions, the burner still emits a significant amount of soot and produces thermal radiation. In this study, a laboratory-scale coflow diffusion burner was developed to examine the effects of fuel composition in combustion products on the soot emission and radiation behavior. The post combustion gas was simulated by adding carbon monoxide and carbon dioxide to two different base fuels: kerosene vapor and ethylene. The radiation flux sensor and laser extinction apparatus were used to measure the radiation intensity and soot emission, respectively, within a flame. The flame length and temperature were measured to examine the combustion behavior of each sooting flame having a strong radiation. Finally, the relationship between soot emission and radiation intensity was proposed based on all the experimental data

One-Dimensional Modeling of an Entrained Coal Gasification Process Using Kinetic Parameters

A one-dimensional reactor model was developed to simulate the performance of an entrained flow gasifier under various operating conditions. The model combined the plug flow reactor (PFR) model with the well-stirred reactor (WSR) model. Reaction kinetics was considered together with gas diffusion for the solid-phase reactions in the PFR model, while equilibrium was considered for the gas-phase reactions in the WSR model. The differential and algebraic equations of mass balance and energy balance were solved by a robust ODE solver, i.e., an semi-implicit Runge–Kutta method, and by a nonlinear algebraic solver, respectively. The computed gasifier performance was validated against experimental data from the literature. The difference in product gas concentration from the equilibrium model, and the underlying mechanisms were discussed further. The optimal condition was found after parameter studies were made for various operating conditions

Study of Floating Wind Turbine with Modified Tension Leg Platform Placed in Regular Waves

In this study, the typical ocean environment was simulated with the aim to investigate the dynamic response under various environmental conditions of a Tension Leg Platform (TLP) type floating offshore wind turbine system. By applying Froude scaling, a scale model with a scale of 1:200 was designed and model experiments were carried out in a lab-scale wave flume that generated regular periodic waves by means of a piston-type wave generator while a wave absorber dissipated wave energy on the other side of the channel. The model was designed and manufactured based on the standard prototype of the National Renewable Energy Laboratory (NREL) 5 MW offshore wind turbine. In the first half of the study, the motion and structural responses for operational wave conditions of the North Sea near Scotland were considered to investigate the performance of a traditional TLP floating wind turbine compared with that of a newly designed TLP with added mooring lines. The new mooring lines were attached with the objective of increasing the horizontal stiffness of the system and thereby reducing the dominant motion of the TLP platform (i.e., the surge motion). The results of surge translational motions were obtained both in the frequency domain, using the response amplitude operator (RAO), and in the time domain, using the omega arithmetic method for the relative velocity. The results obtained show that our suggested concept improves the stability of the platform and reduces the overall motion of the system in all degrees-of-freedom. Moreover, the modified design was verified to enable operation in extreme wave conditions based on real data for a 100-year return period of the Northern Sea of California. The loads applied by the waves on the structure were also measured experimentally using modified Morison equation—the formula most frequently used to estimate wave-induced forces on offshore floating structures. The corresponding results obtained show that the wave loads applied on the new design TLP had less amplitude than the initial model and confirmed the significant contribution of the mooring lines in improving the performance of the system

Spray Formation of a Liquid Carbon Dioxide-Water Mixture at Elevated Pressures

Liquid carbon dioxide-assisted (LCO2-assisted) atomization can be used in coal-water slurry gasification plants to prevent the agglomeration of coal particles. It is essential to understand the atomization behavior of the water-LCO2 mixture leaving the injector nozzle under various conditions, including the CO2 blending ratio, injection pressure, and chamber pressure. In this study, the flash-atomization behavior of a water-LCO2 mixture was evaluated with regard to the spray angle and penetration length during a throttling process. The injector nozzle was mounted downstream of a high-pressure spray-visualization system. Based on the results, the optimal condition for the effective transport of coal particles was proposed

Nanovesicle-based bioelectronic nose platform mimicking human olfactory signal transduction

We developed a nanovesicle-based bioelectronic nose (NBN) that could recognize a specific odorant and mimic the receptor-mediated signal transmission of human olfactory systems. To build an NBN, we combined a single-walled carbon nanotube-based field effect transistor with cell-derived nanovesicles containing human olfactory receptors and calcium ion signal pathways. Importantly, the NBN took advantages of cell signal pathways for sensing signal amplification, enabling similar to 100 times better sensitivity than that of previous bioelectronic noses based on only olfactory receptor protein and carbon nanotube transistors. The NBN sensors exhibited a human-like selectivity with single-carbon-atomic resolution and a high sensitivity of 1 fM detection limit. Moreover, this sensor platform could mimic a receptor-meditated cellular signal transmission in live cells. This sensor platform can be utilized for the study of molecular recognition and biological processes occurring at cell membranes and also for various practical applications such as food screening and medical diagnostics. (C) 2012 Elsevier B.V. All rights reserved.This work was supported by the NRF grant (No. 2011-0000390, 2011-0000331, 2010-0005574, 2011-0020984) and the Conversing Research Center Program (No. 2011K000683, No. 2011K000682). SH acknowledges the support from the WCU program (R31-10032) and the NBIT program (No. 2011-00240).OAIID:oai:osos.snu.ac.kr:snu2012-01/102/0000002410/8SEQ:8PERF_CD:SNU2012-01EVAL_ITEM_CD:102USER_ID:0000002410ADJUST_YN:YEMP_ID:A002014DEPT_CD:458CITE_RATE:5.602FILENAME:(2012.5) Nanovesicle-based bioelectronic nose platform mimicking.pdfDEPT_NM:화학생물공학부EMAIL:[email protected]_YN:NCONFIRM:

Y Combined Effect of Catholyte Gap and Cell Voltage on Syngas Ratio in Continuous CO2/H2O Co-electrolysis

Electrochemical devices are constructed for continuous syngas (CO + H2) production with controlled selectivity between CO2 and proton reduction reactions. The ratio of CO to H2, or the faradaic efficiency toward CO generation, was mechanically manipulated by adjusting the space volume between the cathode and the polymer gas separator in the device. In particular, the area added between the cathode and the ion-conducting polymer using 0.5 M KHCO3 catholyte regulated the solution acidity and proton reduction kinetics in the flow cell. The faradaic efficiency of CO production was controlled as a function of the distance between the polymer separator and cathode in addition to that manipulated by the electrode potential. Further, the electrochemical CO2 reduction device using Au NPs presented a stable operation for more than 23 h at different H2:CO production levels, demonstrating the functional stability of the flow cell utilizing the mechanical variable as an important operational factor.11Nsciescopu