Effect of temperature conditions on the mechanism of formation, molecular structure, and properties of polyurethanes

1982 ◽  
Vol 20 (10) ◽  
pp. 2863-2878 ◽  
Author(s):  
V. P. Dorozhkin ◽  
V. I. Kimelblat
Keyword(s):  
Molecular Structure ◽  
Effect Of Temperature ◽  
Structure And Properties ◽  
Mechanism Of Formation ◽  
Temperature Conditions

scholarly journals Effect of Temperature Conditions on Flame Evolutions of Turbulent Jet Ignition

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2226
Author(s):  
Jiaying Pan ◽  
Yu He ◽  
Tao Li ◽  
Haiqiao Wei ◽  
Lei Wang ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Early Stage ◽  
Turbulent Jet ◽  
Combustion Stability ◽  
Effect Of Temperature ◽  
Main Chamber ◽  
Detailed Chemical Kinetics ◽  
Jet Flame ◽  
Spherical Flame ◽  
Temperature Conditions

Turbulent jet ignition technology can significantly improve lean combustion stability and suppress engine knocking. However, the narrow jet channel between the pre-chamber and the main chamber leads to some difficulties in heat exchange, which significantly affects combustion performance and mechanical component lifetime. To clarify the effect of temperature conditions on combustion evolutions of turbulent jet ignition, direct numerical simulations with detailed chemical kinetics were employed under engine-relevant conditions. The flame propagation in the pre-chamber and the early-stage turbulent jet ignition in the main chamber were investigated. The results show that depending on temperature conditions, two types of flame configuration can be identified in the main chamber, i.e., the normal turbulent jet flame propagation and the spherical flame propagation, and the latter is closely associated with pressure wave disturbance. Under low-temperature conditions, the cold jet stoichiometric mixtures and the vortexes induced by the jet flow determine the early-stage flame development in the main chamber. Under intermediate temperature conditions, pre-flame heat release and leading pressure waves are induced in the jet channel, which can be regarded as a transition of different combustion modes. Whereas under high-temperature conditions, irregular auto-ignition events start to occur, and spherical flame fronts are induced in the main chamber, behaving faster flame propagation.

Mechanism of Formation and Molecular Structure of α-Halothioacetones

2004 ◽  
Vol 74 (4) ◽  
pp. 594-599 ◽  
Author(s):  
V. A. Shagun ◽  
L. G. Shagun ◽  
M. G. Voronkov
Keyword(s):  
Molecular Structure ◽  
Mechanism Of Formation

scholarly journals Polyfluorenylacetylene for near-infrared laser protection: polymer synthesis, optical limiting mechanism and relationship between molecular structure and properties

RSC Advances ◽  
2017 ◽  
Vol 7 (85) ◽  
pp. 53785-53796 ◽  
Author(s):  
Gang Zhao ◽  
Yan Feng ◽  
Shanyi Guang ◽  
Hongyao Xu ◽  
Naibo Lin ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Near Infrared ◽  
Optical Limiting ◽  
High Thermal Stability ◽  
Photon Absorption ◽  
Structure And Properties ◽  
Absorption Mechanism ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Good Solubility

The incorporation of styryl/stilbene–fluorene into polyacetylenes not only endowed the polymers with novel near-infrared optical limiting properties based on a two-photon absorption mechanism but good solubility and high thermal stability.

Sign in / Sign up

Export Citation Format

Share Document