摘要:

Past experimental evidence has shown that acetylene and molecular hydrogen are controlling elements in the reaction bath for PAH (polycyclic aromatic hydrocarbon) growth in fuel-rich premixed combustion. The present work provides experimental evidence that the amount of methane produced from the initial fuel also plays a significant role in determining the rate of PAH formation and needs to be considered as an additional parameter for characterizing the growth environment.

ISSN:0010-2202    

DOI:10.1080/00102200008935819

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

An experimental study to define a practical methodology mat will serve to assess the burning of crude oils on a water sub-layer by means of a bench scale procedure is presented, A modified ASTM-E1321 (LIFT) is combined with flash point measurements to extract fuel properties by means of an existing theoretical formulation. The fuel and water layers are treated as a thermally thick material with combined properties to be able to obtain an analytical solution for an ignition delay time and a flame spread velocity. The experimental results are then correlated to the theoretical formulation to obtain the “fire properties” described in the ASTM-E1321 standard. Five different parameters have been identified that describe the capability of a liquid fuel to sustain a flame: the critical heat flux for ignition, qo.ig,an ignition temperature, Tig,the heat contribution of the flame, φ, a thermal efficiency, a/hTand the thermal inertia, √kρc/a. The methodology is used to evaluate the effect of weathering on the flammability of Alaska North Slope (ANS) and Cook Inlet crude oils. The critical heat flux for ignition was found to be a strong function of the weathering level and a weak function of the fuel layer thickness. The ignition temperature depends on both the weathering level and the fuel layer thickness. Thermal efficiency, heat contribution from the flame and thermal inertia remained invariant with die weathering level and fuel layer thickness.

ISSN:0010-2202    

DOI:10.1080/00102200008935820

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Blended coal that consists of 70% anthracite and 30% bituminous coal is cheaper than pure bituminous coal, but it is very difficult to bum in the revolving cement kiln. To bum the blended coal, a new kind of burner, which is called the burner with velocity difference jets, is used. The combustion processes in the revolving cement kiln are simulated by means of improved multi-fluid model for two-phase turbulent flows with reaction. The better burner construction is decided by simulation, which should not only ensure the ignition and stable combustion for blended coal but also restrain the expansion of pulverized coal flow and make flame not touch the slagging layer of kiln. The results of integral simulation show that the ignition of blended coal is slower than that of bituminous coal, but the flame of blended coal is longer than that of bituminous coal. Thus the use of blended coal not only reduces the cost but also suits wet kiln better

ISSN:0010-2202    

DOI:10.1080/00102200008935821

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We study theoretically the pressure and gas flow fields produced by a deflagration wave as it passes down a cylindrical detonator delay element filled with a porous pyrotechnic. We model the flame front as a planar source of heat and gas which travels down the element with constant speed, thus eliminating the detailed chemistry of the reaction. It is shown that there are two key small dimension-less parameters β (the aspect ratio) and δ (a measure of the permeability of the porous pyrotechnic). The pressure field and mass flow circulation is studied for punctured and sealed elements.

ISSN:0010-2202    

DOI:10.1080/00102200008935822

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The thermochemistry and chemical kinetics for a partially premixed system in turbulent reacting flows are discussed in terms of activation energy asymptotics and a simple presumed pdf based on two delta functions. The resulting analysis permits fuel and products to coexist, i.e., finite rate kinetic effects are incorporated. Emphasis is placed on lean mixtures since these are of greatest applied interest but the analysis pertains to both rich mixtures and those spanning equivalence ratio of unity. Assessment of the thermochemical model is carried out in two ways, the most comprehensive of which involves the flow in a slender channel. Although the fluid mechanical description of this flow is highly simplified, a large number of parameters are found to be needed to characterize the operative aerothermochemical conditions, the implication being that a wide variety of flows are susceptible to treatment.

ISSN:0010-2202    

DOI:10.1080/00102200008935823

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor