Homogeneous Reactor Research Articles

The combustion mechanism of aluminium in the steam/carbon dioxide mixed atmosphere

AbstractThe ignition and combustion characteristics of aluminium (Al) in the steam/carbon dioxide (H2O/CO2) mixed atmosphere were calculated by using a close homogeneous catch reactor and premixed laminar flame‐speed of CHEMKIN‐PRO. The effects of initial reaction temperature and H2O/CO2 ratios on the system temperature, products, and ignition delay time were explored. The main reaction paths were analyzed by the temperature sensitivity. Al (l) entered the system with a pronounced phase transition and only one heating stage, but there are two heating stages in the Al (g) system. The reaction of Al in the H2O/CO2 mixed atmosphere has a positive effect on the ignition delay time of the system. The high contents of CO2 in the H2O/CO2 mixed atmosphere can increase the maximum temperature of system and decrease the ignition delay time. Temperature sensitivity analysis shows that AlO, Al2O, and AlOH are important intermediate products, and Al2O2 is the main substance that produces Al2O3. The dominant reaction path is Al → AlOH→AlO → Al2O → Al2O2 → Al2O3. In addition, when the initial temperature was 2300 K, the laminar flame velocity was calculated to reach 35.6 m/s.

Efficient synthesis of the cyclo-olefin copolymers at high temperature and pressure in a homogeneous mini-tubular reactor

Ethylene-norbornene copolymer (ENC) is one of the most representative cyclo-olefin copolymer (COC). Both the amorphous and semi-crystalline ENCs were efficiently synthesized by the homogeneous solution copolymerization of ethylene (E) and norbornene (NB) using rac-Et(Ind)2ZrCl2/triisobutylaluminium/(Ph3C)B(C6F5)4 ternary catalyst system in a visualized mini-tubular reactor under high temperature (90–130 °C) and given pressure (24 bar). An ultra-high activity of 7.6 × 108 g/(molZr h), as well as considerable efficiency of 14.1 kgENC/gZr was achieved in time of only 30 s at E/NB molar ratio of 3:1. Moreover, a quench-labeling method using 2-thiophenecarbonyl chloride (TPCC) was adopted to calculate the high proportion of active center [C*]/[Zr]. The novel strategy was proposed for preparation of the block semi-crystalline ENC elastomers with excellent tensile performance and high transparency via reversible chain transfer based on spatiotemporal concentration distribution in a mini-tubular reactor.

Comprehensive Assessment of STGSA Generated Skeletal Mechanism for the Application in Flame-Wall Interaction and Flame-Flow Interaction

In this study, we conduct a thorough evaluation of the STGSA-generated skeletal mechanism for C2H4/air. Two STGSA-reduced mechanisms are taken into account, incorporating basic combustion models such as the homogeneous reactor model, one-dimensional flat premixed flame, and non-premixed counterflow flame. Subsequently, these models are applied to more complex combustion systems, considering factors like flame-flow interaction and flame-wall interaction. These considerations take into account additional physical parameters and processes such as mixing frequency and quenching. The results indicate that the skeletal mechanism adeptly captures the behavior of these complex combustion systems. However, it is suggested to incorporate strain rate considerations in generating the skeletal mechanism, especially when the combustion system operates under high turbulent intensity.

Thermal-hydraulic characterization of a 50-kW medicinal-aimed aqueous homogeneous reactor (MAHR)

This paper analyses the thermal–hydraulic performance of a proposed 50-kW aqueous homogeneous reactor (AHR) aimed at producing Mo-99. The reactor thermal–hydraulic characteristics are analyzed using ANSYS-FLUENT software and Relap code, and the results are validated through experiments conducted by a prototypic cylindrical sector of the reactor vessel. Boundary conditions in the CFD simulation are set up based on Relap modelling, while CFD outputs are validated by experimental results achieved using the laboratory model. Then, various parameters, including coolant mass flow rate, first cycle pipe diameter, coolant outlet temperature, average fuel solution temperature, and the elevation difference between the reactor and heat exchanger, are optimized using the least-squares optimization method. Results demonstrate that the heat removal system provides sufficient cooling capacity to ensure stable operation of the proposed AHR core by preventing fuel solution overheating and, consequently, boiling (void formation) in the active fuel solution.

Reforming of ammonia and ammonia-air mixtures in a homogenous plasma reactor: Parametric study of hydrogen yields

Plasma-assisted reforming shows great promise for making ammonia compatible with current engine technology, with minimal modifications required. This study examines the impact of various discharge, flow, and composition parameters on ammonia conversion into hydrogen using a new well-stirred homogeneous plasma reactor. Gas chromatography was used to measure hydrogen and oxygen, while ICCD imaging evaluated plasma homogeneity. Initial mixture composition significantly influences the response to plasma conditions. Relative to the initial ammonia composition, the conversion of pure ammonia yields a lower hydrogen percentage when compared to air-diluted mixtures. Introducing air changes the relationship between pulsed energy deposition and hydrogen production, resulting in a more substantial increase in conversion. Efficiency calculations demonstrate that high ammonia content and high pulse frequencies improve yields, while longer residence times in the reactor result in higher temperatures, also increasing yields. These findings provide insights into the underlying mechanisms of ammonia cracking and reforming in a discharge, and will serve to promote further investigation into plasma reforming strategies.

Numerical Simulation of the Thermal Destruction of Organophosphorous

The organophosphorus class of compounds has several usages nowadays. Some halogenated organophosphorus are used as flame retardants, and others are used as pesticides worldwide. In the last case, those compounds are subject to law regulation. They are now used as chemical weapons in many wars and terrorist attacks. Due to this variety of usages and the high toxicity of such compounds, the study of the proper treatment for residues containing those substances is significant to prevent the degradation of soil, water, and the atmosphere. For these reasons, the present study conducted numeric simulations of the incineration of organophosphorus compounds using kinetic models of combustion and pyrolysis found in the literature. The study of the degradation of this class of substances and the pollutant formation was made by simulating a homogeneous zeroth-order reactor and a continuous stirred tank reactor model. Due to the results of the simulations, the degradation made with the batch mode operation is efficient in the degradation of the substances considered in this work. The stream-containing process products have CO2, CO, HF, HOPO, and HOPO2. The three last cited have no determination about the emission ranges in the legislation, but their concentrations indicate the necessity of treatment for them. Furthermore, it was possible to evaluate the negative influence of the hydrocarbon used as fuel and the presence of CO2 in the degradation of the organophosphate compounds.

Design and simulation of neutron radiography system for an aqueous homogeneous solution reactor

AHR reactors are known for the production of radiopharmaceuticals. The ARGUS reactor is one of the most famous of these reactors, which has been designed originally for radioisotopes production. The ARGUS reactor produces a suitable neutron flux that can be used for other applications such as neutron radiography (NR). Here, a NR system is designed step by step using the Monte Carlo method. The length of the collimator, divergence angle, diameter of the aperture, and thermal column dimension are designed. The designed aperture and thermal column are selected from boron carbide and heavy water, respectively. The depth of the thermal column is changed until the ratio of thermal neutrons to total neutrons (TNC) reached above 90%. The hole inside the thermal column is designed and internal lining is done. The inner lining is made of cadmium and had a thickness of 1 mm, and the space between the inner and outer lining is filled with lead. To reduce the gamma dose to acceptable values, the position of the collimator is changed instead of using a gamma filter. By changing the depth of the hole and creating the convergence angle to the hole, the flux of thermal neutrons will be 1.8E+6 n.cm−2s−1 that satisfy the IAEA suggested values for NR. Then, the uniformity of the radiation field of the neutron flux output from the collimator is obtained. At the end, images of SI and BPI standards are recorded. The good quality and contrast of these images showed the acceptable design of the NR system for the ARGUS reactor.

Subdiffusive processes in BWRs

The objective of this work is the analysis of subdiffusive processes in BWR reactors. Nuclear reactors are highly heterogeneous systems where the phenomena at the reactor scale are not possible to describe with constitutive standard laws (normal diffusion) of energy, momentum, and mass. However, there are methods to achieve it such as the volumetric average to upscale the reactor and incorporate up-scaled constitutive laws. However, it can also be proposed constitutive laws of fractional order to consider anomalous diffusion. For the neutronic processes, the neutron diffusion theory is non-appropriated to the reactor scale, because this theory is applied to the homogeneous reactor. Given the heterogeneity of these systems in describing the dynamic behaviour of BWRs with point models, it represents a challenge to the incorporation of the heterogeneous effects whose main characteristic is that the transport phenomena are subdiffusive with relaxation times (i.e., non-instantaneous) by nature. The point models called reducer-order models are important for stability analysis and to develop control strategies. In linear or nonlinear stability analysis and system control, they are carried out with reduced order models that are zero dimension, i.e., point models that depend exclusively on time. This is because existing methodologies propose mathematical expressions in the time or frequency domain for stability analysis or to establish control strategies. The challenge is for ROM models to be able to consider subdiffusive effects on neutron motion. This is achieved by various routes from the P1 theory that includes the temporal term with relaxation effects (relaxation time) or by proposing a more general constitutive equation of fractional order for the neutron current vector, as is presented in this work. Moreover, the Fractional Order Models behavior must be as a transport theory based model, as well as in those nuclear and thermohydraulic codes which are very useful but complex, for which is sometimes it is impossible to obtain analytical expressions. To incorporate these effects in this work we consider point models of fractional order, which represent the subdiffusive phenomenon when the fractional order (known as anomalous diffusion coefficient) is greater than 0 and less than 1.

Experience in the production of 99Mo from low enriched uranium at the VVR-ts research nuclear facility

The key industrial method for producing 99Mo is production of the radionuclide as one of the 235U fission fragments. 235U is irradiated with neutrons in a nuclear reactor (both heterogeneous and homogeneous nuclear reactors can be used) and then processed in radiochemical laboratories, where 99Mo is chemically extracted from fission products. Both highly enriched uranium (HEU) and low enriched uranium (LEU) can be used to produce 99Mo by the fragmentation method. To date, almost all world producers, with the exception of Russia, are either in the final stages of transferring production from highly enriched uranium to low enriched uranium, or are already producing 99Mo using LEU. This is due to the problems of non-proliferation of nuclear materials and the prevention of the likelihood of terrorist threats. A number of experimental studies have been carried out on the basis of the VVR-ts research reactor. Experimental studies included the study of the effect of LEU targets on the reactivity reserve of the VVR-ts reactor, irradiation of these targets in experimental channels and separation of 99Mo from them. The paper presents the results of producing and separating 99Mo from targets with LEU material. It is shown that it is necessary to improve the processing technology to increase the production of fragmented 99Mo from LEU.

Theoretical and kinetic study of the hydrogen abstraction reactions of ethyl propionate

Ethyl propionate shows great promise as a biodiesel molecule model. However, the current oxidation kinetic model falls short in accurately predicting its combustion behavior. Therefore, this study employed ab initio quantum chemistry methods to analyze the hydrogen abstraction reactions of ethyl propionate with various reactive radicals, including OH, O, H, CH3, C2H3, C2H5, HO2, CH3O and CH3O2, which play a critical role in refining the oxidation kinetics. Theoretical calculations were conducted to determine the rate constants and branching ratios for these reactions at temperatures ranging from 500 K to 2500 K using transition state theory, quasi-rigid rotor harmonic oscillator model, and tunneling correction. After updating the kinetics of hydrogen abstraction reactions in the oxidation mechanism proposed by Metcalfe et al., the modified model was validated by comparing the simulated mole fraction evolutions of ethyl propionate and major products in a jet-stirred reactor, ignition delay in a closed homogeneous batch reactor, and laminar flame speed with experimental data. The findings indicate that the modified model reliably reproduces the experimental data and significantly improves the prediction accuracy for low-temperature combustion of ethyl propionate when compared to the original model.

A comparative analysis of gas-cooled fast reactor using heterogeneous core configurations with three and five fuel variations

GFR or Gas-cooled Fast Reactor is one type of fast generation-IV that uses a very high cooling temperature. Thus, it is necessary to have the right reactor core design so that the power distribution of neutrons produced reaches a safe and even limit point. The use of a uniform (homogeneous) reactor core can produce peaking power. This is very avoidable because it will cause a reactor accident. In this study, researchers tried to compare the results of the analysis for two heterogeneous reactor core designs including the configuration of 3 fuel variations and 5 fuel variations using UN-PuN fuel. This study aims to determine the keff value produced by both types of fuel variations during 5 years of burn-up and determine the characteristics of neutron flux, fission rate, and fission product during 15 years of burn-up. This study was started by calculating the homogeneous and heterogeneous core of 3 and 5 fuel variations with neutron transport simulation involving OpenMC. The calculation results show that the heterogeneous core configuration of 5 fuel variations for the keff value is more optimal than 3 fuel variations, because it has the smallest excess reactivity value. The neutron flux and fission rate characteristics for 5 fuel variations are more evenly distributed when compared to 3 fuel variations to maintain neutron lifetime and reactor life in operation. Burn-up residual plutonium material and minor actinide waste for 5 fuel variations have less mass than 3 fuel variations. The results of neutronic analysis of GFR reactors with heterogeneous reactor core designs for 5 fuel variations are better in terms of reactor criticality, neutron power distribution, and waste produced. Finally, optimization of the UN-PuN fuel volume fraction of 60 % provides the optimal keff value

Research on the Formation Conditions and Preventive Measures of Uranium Precipitates during the Service Process of Medical Isotope Production Reactors.

This study focuses on the Medical Isotope Production Reactor (MIPR), an aqueous homogeneous reactor utilized for synthesizing medical isotopes like 99Mo. A pivotal aspect of MIPR's functionality involves the fuel solution's complex chemical interactions, particularly during reactor operation. These interactions result in the formation of precipitates, notably water filamentous uranium ore and columnar uranium ore, which can impact reactor performance. The research presented here delves into the reactions between liquid fuel uranyl nitrate and key radiolytic products, employing simulation calculations complemented by experimental validation. This approach facilitates the identification of uranium precipitate types and their formation conditions under operational reactor settings. Additionally, the article explores strategies to mitigate the formation of specific uranium precipitates, thereby contributing to the efficient and stable operation of MIPR.

A comparative study on methanol and n-dodecane spray flames using Large-Eddy Simulation

Methanol (CH3OH) is an attractive alternative fuel that can reduce net carbon release and decrease pollutant emissions. In this study, methanol and n-dodecane spray flames were investigated using Large-Eddy Simulation (LES) and direct coupling with finite-rate chemistry. The selected ambient conditions are relevant to engines and were previously unreported for numerical methanol spray studies, i.e. high pressure (60 bar) and temperature (900 – 1200 K) with high injection pressure (1500 bar). The Engine Combustion Network (ECN) Spray A case was used to validate the n-dodecane spray flame. For methanol, a modified ECN Spray A condition was used with a high initial ambient temperature (1100 K-1200 K) to ensure fast enough ignition relevant to engine time scales. The performed homogeneous reactor (0D) simulations revealed a new phenomenon of a two-stage ignition process for methanol, confirmed by the 3D LES at high pressure, high temperature, and lean conditions. The present numerical results also show that: 1) there is a strong ambient temperature sensitivity for methanol ignition delay time (IDT) with a five-fold decrease in IDT (IDT1100K/IDT1200K=5) and a factor of 2.6 decrease in the flame lift-off length (FLOL1100K/FLOL1200K=2.6) as the ambient temperature is increased from 1100 K to 1200 K, 2) methanol spray ignition takes place at a very lean mixture (ϕMR≈0.2) consistent with the 0D predicted most reactive mixture fraction (ZMR), 3) on average, methanol sprays are significantly leaner than n-dodecane sprays at quasi-steady-state (ϕmeoh,ave≈0.2 vs ϕndod,ave≈0.7), implying very low soot emissions, and 4) the methanol spray flames could have similar temperatures as the n-dodecane sprays depending on the initial conditions, thus a similar level of NOx emissions.

Characterization of neutronic parameters and radiation shielding design for an aqueous homogeneous reactor

In this research, an aqueous homogeneous reactor is simulated and its neutronic parameters are investigated. Due to the negative reactivity caused by temperature change and void formation, the cold excess reactivity is considered equal to 4 βeff. Also, calculations of radiation shielding and neutronic characterization of the reactor are performed. For different heights of uranyl sulfate fuel, the effective multiplication factor (keff) of the reactor is calculated under cold zero power and hot full power conditions to assess the required excess reactivity. The amount of fuel burnup and changes in the keff are investigated for 500 days, finally 200 operating days are chosen as the working duration of the reactor. The control rods worth (CRW) for different diameters of boron carbid and reactor safety parameters including shot down margin (SDM) and safety reactivity factor (SRF), temperature and void coefficients of reactivity are analyzed. In order to design a suitable radiation shield for this reactor, two different shields are considered. The first shield is a combination of polyethylene thicknesses and barite concrete, and the second shield is made only of barite concrete. The total thickness of the first and second shield was 230 and 180 cm, respectively. Due to the problems of using polyethylene (e.g. problems related to machining, shield dimensions and low melting temperature), the second shield is chosen as the suitable radiation shield for this reactor. Using this radiation shield, the total dose rates of neutron and gamma rays satisfy the ICRP dose limits.

Estimation and testing of single-step oxidation reactions for hydrogen and methane in low-oxygen, elevated pressure conditions

Advanced combustion concepts, such as moderate or intense low-oxygen dilution (MILD) combustion, offer a reduction in NOx emissions and increased thermal efficiency. MILD is characterised by low-oxygen, high-temperature conditions, where finite-rate chemistry effects are significant. Modelling this regime using reduced or single-step chemistry remains a challenge in part due to the finite-rate chemistry. This work proposes a generalised method for assigning Arrhenius coefficients of a single-step reaction using the outputs of a detailed mechanism. Assigning the typical chemical conservation equation to a progress variable, activation energy and pre-exponential factor for an Arrhenius kinetics global reaction are determined for hydrogen and methane across a number of conditions, with the proposed method extended to n-heptane as well. The temperature exponent in the modified Arrhenius equation is determined by minimising the ignition delay error between detailed and single-step simulations. Functional forms of each coefficient are calculated from a multivariate regression, dependent on initial temperature, pressure, and oxidant mole fraction. The predicted mechanisms are compared against the detailed kinetics in closed homogeneous batch reactors, with comparisons for hydrogen extended to both laminar opposed flow diffusion flames, and computational fluid dynamics (CFD) simulations. Ignition delay and equilibrium temperature are both well predicted for all three fuels in the batch reactors. Notably, the negative temperature coefficient behaviour of n-heptane is successfully recreated with the single-step mechanism. Temperature and heat release of hydrogen flames are well captured in both opposed flow laminar flames, and in turbulent CFD simulations. The computational time was also significantly reduced through the single-step mechanisms, resulting in ∼100 times reduction in compute time for CFD simulations. The function form of the Arrhenius coefficients shows promise for extension outside of the ranges and fuels analysed herein, and presents interesting phenomena for exploring how initial reactant temperature and pressure influence the effective activation energy of an oxidation process.

Comparative Analysis of Turbulence Models for Thermal-Hydraulic Simulations in Aqueous Homogeneous Reactors

This article presents a comparative study of various turbulence models applied in the context of thermal-hydraulic simulations for liquid fuel reactors, specifically Aqueous Homogeneous Reactors (AHR) using Computational Fluid Dynamics. The objective was to assess the suitability of the turbulence models by comparing their results with data obtained from Large Eddy Simulation (LES). For that purpose, was compared the flow behavior predicted using the k-ε, SST, GEKO, DES, SBES, and LES turbulence models. The calculations were carried out in a simplified computational model derived from a pre-existing three-dimensional AHR conceptual design. By utilizing this simplified model, the study aimed to focus on the computational differences between the turbulence models, while minimizing the influence of other factors. The calculation results revealed that the k-ε model exhibited significant discrepancies with the LES, with relative differences for the fuel solution maximum temperature reaching up to 75 %. Among the remaining RANS models, the Shear Stress Transport (SST) model demonstrated the best compromise between accuracy and computational efficiency, with differences below 5 % and requiring only 1/5th of the time, compared to the LES model. The Scale-Resolving Simulation (SRS) models,DES and SBES, provided a more comprehensive description of flow behavior and results closer to LES, albeit with higher computational demands. Between these two models, only the DES model exhibited relative differences below or equal to 1 % compared to the LES model for the studied thermohydraulic parameters.

A co-kurtosis PCA based dimensionality reduction with nonlinear reconstruction using neural networks

For turbulent reacting flow systems, identification of low-dimensional representations of the thermo-chemical state space is vitally important, primarily to significantly reduce the computational cost of device-scale simulations. Principal component analysis (PCA), and its variants, are a widely employed class of methods. Recently, an alternative technique that focuses on higher-order statistical interactions, co-kurtosis PCA (CoK-PCA), has been shown to effectively provide a low-dimensional representation by capturing the stiff chemical dynamics associated with spatiotemporally localized reaction zones. While its effectiveness has only been demonstrated based on a priori analyses with linear reconstruction, in this work, we employ nonlinear techniques to reconstruct the full thermo-chemical state and evaluate the efficacy of CoK-PCA compared to PCA. Specifically, we combine a CoK-PCA-/PCA-based dimensionality reduction (encoding) with an artificial neural network (ANN) based reconstruction (decoding) and examine, a priori, the reconstruction errors of the thermo-chemical state. In addition, we evaluate the errors in species production rates and heat release rates, which are nonlinear functions of the reconstructed state, as a measure of the overall accuracy of the dimensionality reduction technique. We employ four datasets to assess CoK-PCA/PCA coupled with ANN-based reconstruction: zero-dimensional (homogeneous) reactor for autoignition of an ethylene/air mixture that has conventional single-stage ignition kinetics, a dimethyl ether (DME)/air mixture which has two-stage (low and high temperature) ignition kinetics, a one-dimensional freely propagating premixed ethylene/air laminar flame, and a two-dimensional dataset representing turbulent autoignition of ethanol in a homogeneous charge compression ignition (HCCI) engine. Results from the analyses demonstrate the robustness of the CoK-PCA based low-dimensional manifold with ANN reconstruction in accurately capturing the data, specifically from the reaction zones.

The C2H4O isomers in the oxidation of ethylene

A combined rotational spectroscopy, thermochemistry, and kinetic modeling study explores the mechanism of acetaldehyde (ethanal), vinyl alcohol (ethenol), and ethylene oxide (oxirane) formation in the oxidation of ethylene (ethene). Multiplexed quantitative detection of oxidation intermediates and products exiting a SiO2/SiC microreactor at 1700 K is demonstrated with the BrightSpec W-band chirped-pulse Fourier transform millimeter-wave spectrometer. The broadband rotational spectrum contains transitions of formaldehyde (CH2O), methoxy (CH3O), methanol (CH3OH), ketene (CH2CO), acetaldehyde (CH3CHO), syn-vinyl alcohol (syn-CH2CHOH), anti-vinyl alcohol (anti-CH2CHOH), oxirane (c-CH2OCH2), propyne (CH3CCH), and syn-propanal (syn-CH3CH2CHO). We focus on the three C2H4O species and deduce their concentration ratio [CH3CHO]:[CH2CHOH]:[c-CH2OCH2] = 1:0.7(2):0.06(2) by comparing the observed line intensities to those simulated with the PGOPHER software. Detailed thermochemistry of the C2H4O isomers and conformers is provided by Active Thermochemical Tables. The observed excess concentrations of vinyl alcohol and oxirane relative to the more stable acetaldehyde compared to the equilibrium ratio at 1700 K (1:0.087:0.000024), point to direct chemical pathways to these higher energy isomers. The mechanism for the formation of the three C2H4O isomers is analyzed using a 0-D homogenous reactor kinetics simulation for ethylene oxidation. The ratios of the C2H4O isomers concentrations predicted by the kinetic model are compared to the experimental values.

Tabulated chemistry method for fast calculations of detailed chemical kinetics in system level simulations of internal combustion engines

To reduce the emissions from internal combustion engines, new combustion strategies along with alternate fuels blends are currently under investigation. The engine performance and emissions depend primarily on the chemical reactions occurring inside the engine. However, the modeling of reactions in engine simulation models using a detailed reaction mechanism is computationally very expensive, especially for very large mechanisms. Hence, a tabulated chemistry solver is developed in this work to reduce the computational time. The thermochemical states of the mixture are pre-calculated at different engine operating conditions based on homogeneous reactor simulations and stored in a lookup table which can be interpolated during the engine simulations. The present work introduces a novel method for thermochemical mapping between detailed chemistry and tabulated chemistry along with automatic identification of important intermediate species during table generation. The evolution of the thermochemical state of the mixture is described using a progress variable and its derivative. Different progress variables are investigated, and a novel formulation is proposed. The method is then applied to predict the reactions and knock phenomenon as well as the emissions in spark-ignited engines. The results using the tabulated chemistry are in good agreement with the detailed chemistry. The crank angle at the knock onset is predicted with a root-mean-squared error of 0.6 degrees crank angle. The cylinder pressure and temperature are in excellent agreement with the full detailed chemistry solution. The concentration of emissions (CO, NOx etc.) are also in good agreement for a wide range of engine operating conditions. The tabulated chemistry method provided a speedup of ~750 times as compared to detailed chemistry for a mechanism with 679 species. The computational time of the tabulated chemistry method remains constant and independent of the mechanism size. The method can be applied to large parametric studies for engine design, optimization, and calibration.

Effect of Solvent on the Rate of Ozonolysis: Development of a Homogeneous Flow Ozonolysis Protocol.

Herein, we describe the effect of organic solvents on ozone solubility and the rate of ozonolysis reactions using rapid injection NMR spectroscopy. The tabulated solubility and kinetic data allowed for the design of a homogeneous ozonolysis flow reactor capable of delivering precise quantities of dissolved ozone to various olefin substrates.