摘要:

In some technical gas burners the gas stream is subdivided in a number of single jets which will be influenced mutual. The paper shows some results of experiments with very simple town gas and natural gas burners with three and five parallel single jets. Measurements of concentration, flame length, and flame width in free and enclosed multiple flames are described. The results show that there is a simple relation between the flame length of multiple burners and the number of jets and the distances between the central and the outer flames. The data of flame length derived from photography and from the axial concentration of CO agree well; so it is possible to measure the length, the width, and the average value of combustion intensity of flames quickly and with fairly good accuracy.

ISSN:0010-2202    

DOI:10.1080/00102207508946678

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

An asymptotic analysis is presented for the problem of droplet vaporization in a stagnant atmosphere taking into account the unsteady effects in the gas phase. The ratio of the densities of the ambient gas and of the liquid is considered as a small parameter. The results of the classical quasi-steady theories are recovered in the first approximation, and corrections due to unsteady effects are obtained for the vaporization rate and for the droplet lifetime, which are found to be of the order of the square root of the density ratio

ISSN:0010-2202    

DOI:10.1080/00102207508946679

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

A semi-empirical model for computing the ion concentration in premixed hydrocarbon flames is developed. The model takes the kinetics of ion formation and recombination, ambipolar diffusion, and convection into account, but depends on a prior knowledge of the flame kinetics. Dimensionless variables which influence the ion distribution and are related to the Damkohler similarity groups are identified. Computed ion profiles are in reasonable agreement with experimental results.

ISSN:0010-2202    

DOI:10.1080/00102207508946680

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

ISSN:0010-2202    

DOI:10.1080/00102207508946681

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Often in combustion engineering, when unpremixed gaseous reactants are burned in a low-speed shear flow, product formation is controlled by the rate of mixing, rather than by the rate of reaction. The reaction mechanism is usually modeled as a direct one-step irreversible reaction, with Lewis-Semenov number taken as unity. For laminar flow, Burke and Schumann suggested how knowledge of a passive scalar in the same flow field as the reactants, satisfying similar boundary conditions, and possessing identical diffusion coefficients, furnishes the diffusion-flame solution. Analogously, for the turbulent case, under almost identical constraints, Toor indicated how knowledge of the mean field and probability density function for a passive scalar in an inert flow yields the mean-field behavior of the turbulent diffusion flame in the same flow. The only additional condition is that, in general, the heat associated with chemical reaction must not alter the dynamics. Here, Toor's method is extended to the two-step symmetrical chain reaction of interest in chemical lasers. The highly nonGaussian probability density function implied by large-scale turbulent structure observed in, at least, portions of the two-dimensional mixing layer downstream of a splitter plate is developed further.

ISSN:0010-2202    

DOI:10.1080/00102207508946682

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

A simple model for carbon monoxide in gas turbines is developed. For typical engine idling and full power conditions the model examines the effect of the parameters equivalence ratio, residence time and degree of mixing on both the equilibrium carbon monoxide concentration and the approach to this level within the various regions of the combustor. The model is largely intended to be interpretive rather than predictive, but the curves presented enable one to qualitatively follow reported trends in carbon monoxide emission levels with the above parameters. Finally suggestions are made for minimizing carbon monoxide emissions at the idling condition.

ISSN:0010-2202    

DOI:10.1080/00102207508946683

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Data are given on the formation of NO and NO∞. in the forward stagnation region of flames surrounding burning cylinders simulating the droplet combustion of n-heptane and ethanol. Temperature profiles are also given and it was found that the maximum yields of NO and NO∞were situated towards the lean side of the maximum flame temperature. In addition HCN concentrations have been measured. It has been shown that considerable NO is formed near the liquid surface by a prompt-NO mechanism. The addition of fuel-nitrogen in the form of pyridine enhanced the level of NO but did not increase the amount of HCN formed

ISSN:0010-2202    

DOI:10.1080/00102207508946684

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The spontaneous ignition composition limits of four flame systems—cool, blue, yellow plume and transition—have been mapped out for the n-butane system in a dynamic flow reactor at atmospheric pressure. The cool and blue flames occur within as well as outside the fuel-oxidizer concentration limits for n-butane hot flames.

ISSN:0010-2202    

DOI:10.1080/00102207508946685

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Nonmetallized double-base propellant and ammonium perchlorate (AP)/binder sandwich combustion were studied in standard and high acceleration environments in order to determine the acceleration sensitive combustion mechanisms. Experimental techniques used were high speed motion pictures, two-color schlieren, and centrifuge mounted combustion bombs. It was found for double-base propellant that the temperature increased continuously from the surface into the visible flame. Acceleration induced burning rate augmentation occurred and resulted in elimination of the visible flame. A modified surface or subsurface zone is proposed as the acceleration sensitive combustion mechanism. AP/binder sandwich combustion was also found to be acceleration sensitive with binder flow-AP interactions proposed as the mechanism.

ISSN:0010-2202    

DOI:10.1080/00102207508946686

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor