San Diego, CA, United States
San Diego, CA, United States

Reaction Design is a San Diego-based developer of combustion simulation software used by engineers to design cleaner burning and fuel-efficient combustors and engines, found in everything from automobiles to turbines for power generation and aircraft propulsion to large diesel engines that use pistons the size of rooms to propel ships locomotives. The technology is also used to model spray vaporization in electronic materials processing applications and predict mixing reactions in chemical plants. ANSYS, a leader in engineering simulation software, acquired Reaction Design in January 2014. Wikipedia.

Time filter

Source Type

Naik C.V.,Reaction Design | Puduppakkam K.V.,Reaction Design | Modak A.,Reaction Design | Meeks E.,Reaction Design | And 3 more authors.
Combustion and Flame | Year: 2011

Blends of n- and iso-alkane components are employed as surrogates for Fischer-Tropsch (F-T) and biomass-derived jet fuels. The composition of the blends has been determined based on data available for two F-T fuel samples obtained from different sources, using a systematic optimization approach. A detailed chemical kinetic mechanism for combustion of the surrogate blends has been assembled. The mechanism has been validated against fundamental experimental data. While drawing initially from other studies in the literature, the mechanism has been improved by enforcing self-consistency of the kinetic and thermodynamic data for the various surrogate-fuel components represented by the mechanism. These improvements have led to more accurate predictions of flame propagation, flame extinction, and NO. x emissions. As part of the validation process, simulations were performed for a wide variety of experimental configurations, as well as for a wide range of temperatures and equivalence ratios for fuel/air mixtures. Comparison of the model predictions to the available literature data confirms the accuracy of the mechanism as well as of the approach for selecting the surrogate blends. © 2010 The Combustion Institute.

Westbrook C.K.,Lawrence Livermore National Laboratory | Naik C.V.,Reaction Design | Herbinet O.,University of Lorraine | Pitz W.,Lawrence Livermore National Laboratory | And 3 more authors.
Combustion and Flame | Year: 2011

A detailed chemical kinetic reaction mechanism is developed for the five major components of soy biodiesel and rapeseed biodiesel fuels. These components, methyl stearate, methyl oleate, methyl linoleate, methyl linolenate, and methyl palmitate, are large methyl ester molecules, some with carbon. carbon double bonds, and kinetic mechanisms for them as a family of fuels have not previously been available. Of particular importance in these mechanisms are models for alkylperoxy radical isomerization reactions in which a C. C double bond is embedded in the transition state ring. The resulting kinetic model is validated through comparisons between predicted results and a relatively small experimental literature. The model is also used in simulations of biodiesel oxidation in jet-stirred reactor and intermediate shock tube ignition and oxidation conditions to demonstrate the capabilities and limitations of these mechanisms. Differences in combustion properties between the two biodiesel fuels, derived from soy and rapeseed oils, are traced to the differences in the relative amounts of the same five methyl ester components. © 2010 The Combustion Institute.

Puduppakkam K.V.,Reaction Design | Liang L.,Reaction Design | Naik C.V.,Reaction Design | Meeks E.,Reaction Design | And 2 more authors.
SAE International Journal of Engines | Year: 2011

A multi-component fuel model is used to represent gasoline in computational fluid dynamics (CFD) simulations of a dual-fuel engine that combines premixed gasoline injection with diesel direct injection. The simulations employ detailed-kinetics mechanisms for both the gasoline and diesel surrogate fuels, through use of an advanced and efficient chemistry solver. The objective of this work is to elucidate kinetics effects of dual-fuel usage in Reactivity Controlled Compression Ignition (RCCI) combustion. The model is applied to simulate recent experiments on highly efficient RCCI engines. These engine experiments used a dual-fuel RCCI strategy with port-fuel-injection of gasoline and early-cycle, multiple injections of diesel fuel with a conventional diesel injector [ 1 ]. The experiments showed that the US 2010 heavy-duty NO x and soot emissions regulations were easily met without aftertreatment, while achieving greater than 50% net indicated thermal efficiency. However, as with other low-temperature combustion strategies, CO and unburnt hydrocarbon emissions must be controlled. Homogeneous charge compression ignition (HCCI) engine experiments were also earlier performed and simulated using a less detailed primary-reference-fuel (PRF) mechanism and single-component surrogates [ 1 ]. The present work introduces a more accurate multi-component representation of the gasoline and a more detailed kinetics mechanism for both the gasoline and diesel surrogates. The simulation results show accurate representation of combustion phasing and better predictions of unburned hydrocarbons and CO emissions as an outcome of using the detailed kinetics. The model demonstrates that the most-reactive surrogate component, n-heptane (component in both diesel and gasoline) ignites first, and the other, slower gasoline-surrogate components follow. The model also shows that the slowest gasoline surrogate component, toluene, is found disproportionately in the unburned hydrocarbon (UHC) emissions. Overall, the predicted UHC emissions can be broadly classified into three groups: surrogate-fuel species make up 37 wt%, large hydrocarbon intermediates that form from the surrogate fuels form 42 wt%, and small C 1 -C 4 hydrocarbons form 21 wt%. Of the surrogate fuels present, toluene has the largest concentration. Analysis of uncertainties in IVC temperature input on emissions predictions has also been performed. As the combustion phasing is retarded, the UHC and CO emissions increase for the base case and the uncertainties in temperature have a more dominant effect on emissions. © 2011 SAE International.

Conradi M.,Reaction Design | Junkers T.,Reaction Design
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2013

The [2 + 2] photocycloaddition between maleimide and various alkenes was optimized in a simple custom-made UV flow reactor. While complete maleimide conversion is only achieved with excesses of at least 10 eq. of alkene and reaction times of 12-24 h in batch, complete reactions with yields in the range >98% could be obtained in 5 min in the flow reactor under strictly equimolar conditions. Functional alkenes carrying allyl, alcohol, amine and ether moieties were successfully conjugated in good yields under optimized reaction conditions. As is demonstrated, the reaction gains in flow most characteristics of a high-efficient reaction, making the process highly valuable for upscaled synthesis of maleimide conjugates. © 2013 Elsevier B.V. All rights reserved.

Naik C.V.,Reaction Design | Puduppakkam K.,Reaction Design | Meeks E.,Reaction Design
SAE International Journal of Fuels and Lubricants | Year: 2010

At temperatures below 1100 K, the oxidation of nitric oxide (NO) impacts the oxidation of hydrocarbons, causing a sensitization effect in fuel combustion. This effect can be important in engine operations, especially those involving high levels of exhaust-gas recirculation (EGR). Many researchers have observed this NO sensitization for the oxidation of hydrocarbons in HCCI engines as well as stirred reactors. They used several model-fuel components relevant to gasoline, such as n-heptane, iso-octane, and toluene. As found in stirred reactor experiments, NO tends to increase the extent of oxidation for high-octane fuel components, such as iso-octane and toluene. However, for the low-octane component n-heptane, NO has an inhibiting effect on hydrocarbon oxidation, particularly at low temperatures corresponding to the negative temperature coefficient (NTC) region. In this study, a detailed reaction mechanism for the combustion of complex gasoline surrogates has been extended to incorporate the sensitization effect of NOx on the oxidation of hydrocarbons. The NOx sub-mechanism incorporates recent updates in the kinetics literature for the hydrogen cyanide and related chemistry, as well as various production pathways that lead to NOx emissions from fuel combustion. The gasoline-NOx mechanism contains 1833 species and 8764 elementary reaction steps, including formation of several polycyclic aromatic hydrocarbons (PAH) species. The extended self-consistent surrogate mechanism has been validated against available stirred-reactor measurements that cover a range of pressures, temperatures, and equivalence ratios for various small and large hydrocarbon components included in the mechanism. It successfully captures NO's inhibiting effect for n-heptane at temperatures below 650 K as well as its promoting effects at higher temperatures. Though validation data are not available for all the components of a complex gasoline surrogate, self-consistency of the mechanism that is built on rate-rules should guarantee the predictive capability for other components as well as their blends. In addition to the validation using the limited fundamental experimental data available, modeling using the detailed reaction mechanism has been performed for a typical gasoline HCCI engine using an eight-component gasoline surrogate. Higher levels of NO are predicted to significantly advance the combustion phasing due to the sensitization effect. The expected effect of exhaust gas recirculation (EGR) on combustion phasing and emissions has also been discussed.[CN1] © 2010 SAE International.

Shi Y.,University of Wisconsin - Madison | Liang L.,Reaction Design | Ge H.-W.,University of Wisconsin - Madison | Reitz R.D.,University of Wisconsin - Madison
Combustion Theory and Modelling | Year: 2010

Acceleration of the chemistry solver for engine combustion is of much interest due to the fact that in practical engine simulations extensive computational time is spent solving the fuel oxidation and emission formation chemistry. A dynamic adaptive chemistry (DAC) scheme based on a directed relation graph error propagation (DRGEP) method has been applied to study homogeneous charge compression ignition (HCCI) engine combustion with detailed chemistry (over 500 species) previously using an R-valuebased breadth-first search (RBFS) algorithm, which significantly reduced computational times (by as much as 30-fold). The present paper extends the use of this on-the-fly kinetic mechanism reduction scheme to model combustion in direct-injection (DI) engines. It was found that the DAC scheme becomes less efficient when applied to DI engine simulations using a kinetic mechanism of relatively small size and the accuracy of the original DAC scheme decreases for conventional non-premixed combustion engine. The present study also focuses on determination of search-initiating species, involvement of the NOx chemistry, selection of a proper error tolerance, as well as treatment of the interaction of chemical heat release and the fuel spray. Both the DAC schemes were integrated into the ERC KIVA-3v2 code, and simulations were conducted to compare the two schemes. In general, the present DAC scheme has better efficiency and similar accuracy compared to the previous DAC scheme. The efficiency depends on the size of the chemical kinetics mechanism used and the engine operating conditions. For cases using a small n-heptane kinetic mechanism of 34 species, 30% of the computational time is saved, and 50% for a larger n-heptane kinetic mechanism of 61 species. The paper also demonstrates that by combining the present DAC scheme with an adaptive multi-grid chemistry (AMC) solver, it is feasible to simulate a direct-injection engine using a detailed n-heptane mechanism with 543 species with practical computer time. © 2010 Taylor & Francis.

Naik C.V.,Reaction Design | Puduppakkam K.,Reaction Design | Meeks E.,Reaction Design
SAE International Journal of Engines | Year: 2013

3-D Computational Fluid Dynamics (CFD) simulations have been performed using a detailed reaction mechanism to capture the combustion and emissions behavior of an IFP Energies Nouvelles optical diesel engine. Simulation results for in-cylinder soot volume fraction (SVF) have been compared to experimental data reported by Pires da Cruz et al. [1] for the engine operating in low-temperature combustion (LTC) mode with high EGR, and for varied operating conditions. For the simulations, a 4-component surrogate blend containing n-hexadecane, heptamethylnonane, 1-methylnaphthalene, and decalin was used to represents the chemical and physical properties of the standard European diesel used in the engine tests. A validated detailed surrogate mechanism containing 392 species and 2579 reactions was employed to model the chemistry of fuel combustion and emissions. In addition, a new pseudo-gas soot model was developed and coupled with the fuel chemistry to simulate in-cylinder soot nucleation, growth, and oxidation processes. A 60° sector mesh containing 53500 cells was used for the engine simulations using the FORTÉ CFD simulation software. Comparisons of calculated incylinder soot volume fractions to those measured show good agreement for crank-angle-resolved SVF. Soot production nominally begins as soon as the combustion starts around 6 crank angle degrees (CAD) after TDC, and peaks approximately 12 CAD after TDC when soot oxidation begin to dominate. Simulations captured the location of soot in the center of the bowl just above the wall, and trends in SVF with variation in operating parameters, including fuel loading, EGR, injection timing, and intake temperature. Advancing injection timing and increasing fuel loading increases peak soot levels, whereas lower EGR and lower intake temperatures lower peak soot levels. Simulations also capture the trends in other emissions for varied operating conditions. Further analyses have been performed to understand the combustion and emissions processes. Copyright © 2013 SAE International.

Naik C.V.,Reaction Design | Westbrook C.K.,Lawrence Livermore National Laboratory | Herbinet O.,University of Lorraine | Pitz W.J.,Lawrence Livermore National Laboratory | Mehl M.,Lawrence Livermore National Laboratory
Proceedings of the Combustion Institute | Year: 2011

New chemical kinetic reaction mechanisms are developed for two of the five major components of biodiesel fuel, methyl stearate and methyl oleate. The mechanisms are produced using existing reaction classes and rules for reaction rates, with additional reaction classes to describe other reactions unique to methyl ester species. Mechanism capabilities were examined by computing fuel/air autoignition delay times and comparing the results with more conventional hydrocarbon fuels for which experimental results are available. Additional comparisons were carried out with measured results taken from jet-stirred reactor experiments for rapeseed oil methyl ester fuels. In both sets of computational tests, methyl oleate was found to be slightly less reactive than methyl stearate, and an explanation of this observation is made showing that the double bond in methyl oleate inhibits certain low temperature chain branching reaction pathways important in methyl stearate. The resulting detailed chemical kinetic reaction mechanism includes more approximately 3500 chemical species and more than 17,000 chemical reactions. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

Reaction Design | Date: 2012-04-13

Method and apparatus for reducing chemical reaction mechanisms are disclosed. A method comprises obtaining data for one or more chemical species in a chemical reaction model from a database, the database including properties of the one or more chemical species; grouping the chemical species in a chemical reaction model into one or more isomer groups according to molecular properties of the chemical species; assigning a representative isomer to at least one isomer group; replacing, in one or more chemical reaction equations of the chemical reaction model, one or more groups of chemical species with a corresponding representative isomer; and executing the chemical reaction model by an apparatus to determine results.

Loading Reaction Design collaborators
Loading Reaction Design collaborators