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Autoignition Of N-Decane Under Elevated Pressure And Low-To-Intermediate Temperature Conditions, Kamal Kumar, Gaurav Mittal, Chih-Jen Sung
Autoignition Of N-Decane Under Elevated Pressure And Low-To-Intermediate Temperature Conditions, Kamal Kumar, Gaurav Mittal, Chih-Jen Sung
Dr. Gaurav Mittal
. The current experiments span a temperature range not fully investigated in previous autoignition studies on n-decane. Two-stage ignition, characteristic of large hydrocarbons, is observed over the entire range of conditions investigated, as demonstrated in the plots of raw experimental pressure traces. In addition, experimental results reveal the sensitivity of the first-stage and total ignition delays to variations in fuel and oxygen mole fractions, pressure, and temperature. Predictability of two kinetic mechanisms is compared against the present data. Discrepancies are noted and discussed, which are of direct relevance for further improvement of kinetic models of n-decane at conditions of elevated …
Cfd Modeling Of Two-Stage Ignition In A Rapid Compression Machine: Assessment Of Zero-Dimensional Approach, Gaurav Mittal, Mandhapati Raju, Chin-Jen Sung
Cfd Modeling Of Two-Stage Ignition In A Rapid Compression Machine: Assessment Of Zero-Dimensional Approach, Gaurav Mittal, Mandhapati Raju, Chin-Jen Sung
Dr. Gaurav Mittal
In modeling rapid compression machine (RCM) experiments, zero-dimensional approach is commonly used along with an associated heat loss model. The adequacy of such approach has not been validated for hydrocarbon fuels. The existence of multi-dimensional effects inside an RCM due to the boundary layer, roll-up vortex, non-uniform heat release, and piston crevice could result in deviation from the zero-dimensional assumption, particularly for hydrocarbons exhibiting two-stage ignition and strong thermokinetic interactions. The objective of this investigation is to assess the adequacy of zero-dimensional approach in modeling RCM experiments under conditions of two-stage ignition and negative temperature coefficient (NTC) response. Computational fluid …
Computational Assessment Of An Approach For Implementing Crevice Containment In Rapid Compression Machines, Gaurav Mittal, Sudhir Gupta
Computational Assessment Of An Approach For Implementing Crevice Containment In Rapid Compression Machines, Gaurav Mittal, Sudhir Gupta
Dr. Gaurav Mittal
In Rapid compression machines (RCMs), creviced pistons are often employed to suppress the formation of the roll-up vortex. The use of a creviced piston, however, can enhance other multi-dimensional effects especially during the first-stage of the two-stage ignition. Such multi-dimensional effects can be avoided by using ‘crevice containment’ in which the crevice zone is separated from the main reaction chamber at the end of compression. In this work, an approach for the implementation of ‘crevice containment’ in RCMs is assessed through reactive and nonreactive CFD simulations for a stepped combustion chamber geometry in which ‘crevice containment’ is achieved by using …
A Numerical Assessment Of The Novel Concept Of Crevice Containment In A Rapid Compression Machine, Gaurav Mittal, Mandhapati Raju, Anil Bhari
A Numerical Assessment Of The Novel Concept Of Crevice Containment In A Rapid Compression Machine, Gaurav Mittal, Mandhapati Raju, Anil Bhari
Dr. Gaurav Mittal
Rapid compression machines (RCMs) typically incorporate creviced pistons to suppress the formation of the roll-up vortex. The use of a creviced piston, however, can enhance other multi-dimensional effects inside the RCM due to the crevice zone being at lower temperature than the main reaction chamber. In this work, such undesirable effects of a creviced piston are highlighted through computational fluid dynamics simulations of n-heptane ignition in RCM. Specifically, the results show that in an RCM with a creviced piston, additional flow of mass takes place from the main combustion chamber to the crevice zone during the first-stage of the two-stage …