CARS flames

CC is the other dominant product of hydrocarbon-fueled combustion and its CARS flame spectrum (23)is displayed in Figure 1A. The spectrum is complicated by Fermi resonance and the fact that the rotational transitions are closely overlapped. This precludes treating them as independently broadened and so-called collisional narrowing may need to be taken into account. Computer modelling is currently in progress. Since all hydrocarbon fuels are Raman-active,CARS should ultimately be capable of monitoring total hydrocarbon concentrations during combustion as well. 

Taran, J.P., "CARS Flame Diagnostics" presented at the CARS meeting of the Institute of Physics, AERE Harwell, March 1979. 

An interesting variation of Raman spectroscopy is coherent anti-Stokes Raman spectroscopy (CARS) (99). If two laser beams, with angular frequencies CO and CO2 are combined in a material, and if cjj — is close to a Raman active frequency of the material, then radiation at a new frequency CJ3 = 2cJ2 — may be produced. Detection of this radiation can be used to characterize the material. Often one input frequency is fixed and the other frequency, from a tunable laser, varied until matches the Raman frequency. CARS has the capabiHty for measurements in flames, plasmas, and... 

A visible cloud of vapor, 1 m deep, spread for 150 m and was ignited by a car that had stopped on a nearby road 25 minutes after the leak started. The road had been closed by the police, but the driver approached from a side road. The fire flashed back to the sphere, which was surrounded by flames. There was no explosion. The sphere was fitted with water sprays. But the system was designed to deliver only haif the quantity of water normally reeommended (0.2 U.S. gal/ft- min. or 8 L/m min.), and the supply was inadequate. When the fire brigade started to use its hoses, the supply to the spheres ran dry. The firemen seemed to have used most of the available w ater for cooling neighboring spheres to stop the fire from spreading, in the belief that the relief valve would pro-teet the vessel on fire. 

Flames were first observed at or near an unoccupied caboose. A flash fire resulted, propagating toward the punctured car area. An orange flame then spread upward, and a large vapor cloud flared with explosive force. Estimates of the time lapse between these occurrences range from 2 to 30 seconds. Almost immediately thereafter, a second, more severe, explosion was reported. ... 

Volume changes also can be mechanically determined, as in the combustion cycle of a piston engine. If V=V(i) is an explicit function of time. Equations like (2.32) are then variable-separable and are relatively easy to integrate, either alone or simultaneously with other component balances. Note, however, that reaction rates can become dependent on pressure under extreme conditions. See Problem 5.4. Also, the results will not really apply to car engines since mixing of air and fuel is relatively slow, flame propagation is important, and the spatial distribution of the reaction must be considered. The cylinder head is not perfectly mixed. 

Toyobo has developed high strength polyester tire cords, flame-resistant polyester (HEIM) that contribute to the improvement of car safety and helps save labor in manufacturing processes [40]. 

P. Magre, P. Moreau, G. Collin, R. Borghi, and M. Pealat 1988, Further studies by CARS of premixed turbulent combustion in high velocity flow. Combust. Flame 71 147-168. 

This reaction is energetically spontaneous, but it occurs quite slowly if the gases are just mixed because the activation energy to reaction is too high at 80 kJ mol-1. The reaction is much faster if the CO is burnt, but a naked flame is considered unsafe in a car exhaust. 

The combustion of gasoline is a fast and highly exothermic reaction. Gasoline is stored in a car s fuel tank, where it is exposed to oxygen in the air. Why does gasoline in a fuel tank not burst into flames spontaneously ... 

Harrad S, Ibarra C, Abdallah MA, Boon R, Neels H, Covaci A (2008) Concentrations of brominated flame retardants in dust from United Kingdom cars, homes and offices causes of variability and implications for human exposure. Environ Int 34 1170-1175... 

An inflammable PE sponge that does not release any toxic gas when in contact with fire has been developed by Sanwa Kako Co.Ltd. The inner side of the polyethylene is chemically coated with a flame retardant using electron beam technology. The material is claimed to be suitable for use in car seats, furniture and cushions. Commercial production of the material is planned for late 1993. This abstract includes all the information contained in the original article. 

Mayer, E., Car us, H., Analysis of Flame Propagation Based on Simplified Reaction... 

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