Computed structure of low strain rate partially premixed CH4/air counterflow flames: implications for NO formation

AbstractThe cylindrical samples of TC4 titanium alloy prepared by spark plasma sintering (SPS) were compressed with hot deformation of 70% on the thermosimulation machine of Gleeble-1500. The temperature of the processes ranged from 850°C to 1,050°C, and the strain rates varied between 0.001 and 5 s−1. The relative density of the sintered and compressed samples was measured by the Archimedes principle. During hot deformation, the microstructure of the sample was observed. The results show that the average relative density of the samples was 90.2% after SPS. And the relative density was about 98% after the hot deformation of 70%. Under high temperature (>950°C), the sensitivity of flow stress to temperature was reduced. At low strain rate (0.001 s−1), the increase in the deformation temperature promoted the growth of dynamic recrystallization (DRX). At the same temperature, the increase in strain rate slowed down the growth of DRX grains. And the variation tendency was shown from the basket-weave structure to the Widmanstätten structure at a low strain rate (<0.1 s−1), with increase in the strain rate.

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Evaluation of threshold stress intensity in high strength hydrogen charged steel in low strain rate tension tests

Materials Science and Technology ◽

10.1179/mst.1993.9.11.1009 ◽

1993 ◽

Vol 9 (11) ◽

pp. 1009-1013 ◽

Cited By ~ 2

Author(s):

B. Ule ◽

F. Vodopivec ◽

L. Vehovar ◽

J. Žvokelj ◽

L. Kosec

Keyword(s):

Stress Intensity ◽

Strain Rate ◽

Threshold Stress ◽

High Strength ◽

Threshold Stress Intensity ◽

Tension Tests ◽

Low Strain Rate

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Looking for the hidden morphological signature of active faults in a Low Strain Rate region: clues from the eastern Kachchh region (NW India)

10.5194/egusphere-egu21-15982 ◽

2021 ◽

Author(s):

Eshaan Srivastava ◽

Nicolò Parrino ◽

Javed Malik ◽

Fabrizio Pepe ◽

Pierfrancesco Burrato

Keyword(s):

Strain Rate ◽

Multidisciplinary Approach ◽

Surface Deformation ◽

Active Faults ◽

Tectonic Geomorphology ◽

Seismic Events ◽

Rate Region ◽

Ongoing Work ◽

Morphotectonic Evolution ◽

Low Strain Rate

The Kachchh region (NW India), a pericratonic rift basin delimited by E-W trending major thrust faults, is a Low Strain Rate region[PB1]&#160;. In this area, the tectonic forcing magnitude is stronger enough to trigger infrequent significant earthquakes but not enough to overprint the climatic forcing signature. As a consequence, the active faults sources of the largest seismic events are largely poorly known and their geomorphic signature is subdued.&#160;Instrumental and paleoseismological evidence highlights that the eastern part of Kachchh experienced a significant number of seismic events such as the 1819-06-16 Allah Bund earthquake (Mw 7.8, also known as the Rann of Kutch earthquake), the 1956-07-21 Anjar earthquake (Mw 6.1), the 2001-01-26 Bhuj earthquake (Mw 7.6) and the 2006 events (Mw 5.0 and 5.6 earthquake occurred along Island Belt Fault and Gedi fault).&#160;In this region, the unavailability of useful outcrop information due to a significant climatic overprinting of the fault&#8217;s morphological signatures hampers the detection and parametrization of actively deforming faults.For this reason, in this ongoing work, we propose a multidisciplinary approach, aimed at detecting active geological structures and their related [PB2]&#160;surface deformation, which mainly consists of quantitative tectonic geomorphology and paleoseismological analyses and structural interpretation and modelling. Preliminary results are a morphotectonic evolution model and 3D fault model of the study area. Finally, we stress the concept that only a multidisciplinary approach could provide useful information to understand better the highly debated active tectonic framework of the study area.

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Effects of strain rate and CO2 on no formation in CH4/N2/O2 counter-flow diffusion flames

Thermal Science ◽

10.2298/tsci170922062r ◽

2018 ◽

Vol 22 (Suppl. 2) ◽

pp. 769-776

Author(s):

Fei Ren ◽

Longkai Xiang ◽

Huaqiang Chu ◽

Weiwei Han

Keyword(s):

Strain Rate ◽

Diffusion Flames ◽

Numerical Study ◽

Flame Temperature ◽

Co2 Concentration ◽

No Production ◽

Counter Flow ◽

Detailed Chemistry ◽

No Formation ◽

Key Factor

The reduction of nitrogen oxides in the high temperature flame is the key factor affecting the oxygen-enriched combustion performance. A numerical study using an OPPDIF code with detailed chemistry mechanism GRI 3.0 was carried out to focus on the effect of strain rate (25-130 s?1) and CO2 addition (0-0.59) on the oxidizer side on NO emission in CH4 / N2 / O2 counter-flow diffusion flame. The mole fraction profiles of flame structures, NO, NO2 and some selected radicals (H, O, OH) and the sensitivity of the dominant reactions contributing to NO formation in the counter-flow diffusion flames of CH4\/ N2 /O2 and CH4 / N2 / O2 / CO2 were obtained. The results indicated that the flame temperature and the amount of NO were reduced while the sensitivity of reactions to the prompt NO formation was gradually increased with the increasing strain rate. Furthermore, it is shown that with the increasing CO2 concentration in oxidizer, CO2 was directly involved in the reaction of NO consumption. The flame temperature and NO production were decreased dramatically and the mechanism of NO production was transformed from the thermal to prompt route.

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