Premixing quality and flame stability: A theoretical and experimental study

Models for predicting flame ignition and blowout in a combustor primary zone are presented. A correlation for the blowoff velocity of premixed turbulent flames is developed using the basic quantities of turbulent flow, and the laminar flame speed. A statistical model employing a Monte Carlo calculation procedure is developed to account for nonuniformities in a combustor primary zone. An overall kinetic rate equation is used to describe the fuel oxidation process. The model is used to predict the lean ignition and blow out limits of premixed turbulent flames; the effects of mixture nonuniformity on the lean ignition limit are explored using an assumed distribution of fuel-air ratios. Data on the effects of variations in inlet temperature, reference velocity and mixture uniformity on the lean ignition and blowout limits of gaseous propane-air flames are presented

Radiation-affected laminar flame propagation

Increased laminar flame thickness and flame speed under the influence of radiation is shown in terms of an original heat transfer number where is the weighted nongreyness, [kappa]p and [kappa]R are the Planck mean and the Rosseland mean of the absorption coefficient, [tau] = [kappa]M[delta]K is optical thickness, the mean absorption, [delta]K the conduction flame thickness, P = 4[sigma]TM3/([lambda]/[delta]K) the Planck number, TM the adiabatic flame temperature, [lambda] the thermal conductivity, and [omega] the albedo, the ratio of scattering to extinction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24110/1/0000367.pd

Radiation-affected laminar flame quenching

Under the influence of radiation, the increase in Peclet number characterizing the flame quench distance [Delta], , and the decrease in flame temperature are shown in terms of an original radiation number , where [varrho] is the density, cp the specific heat at constant pressure, Su the laminar flame speed, Tb the flame temperature, subscript u the unburned gas and superscript 0 the adiabatic gas, [lambda] the thermal conductivity, [eta] = ([kappa]P/[kappa]R)1/2 the weighted nongrayness, [kappa]P and [kappa]R being the Planck mean and the Rosseland mean of the absorption coefficient, [epsilon]w the wall emissitivity, [tau]=[kappa]Ml the optical thickness, [kappa]M=([kappa]P[kappa]R)1/2 being the mean absorption coefficient and l a characteric length (related to geometry or quench distance), [omega] the albedo of single scattering, and Bb0 the adiabatic flame Boltzmann number. , where Eb is the blackbody emissive power.It is qualitatively shown that the contribution of radiation to the heat transfer and the laminar flame quenching in small diesel engines can be as much as 35%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24736/1/0000158.pd

Expériences récentes en Pologne en matière de coopération avec des industries occidentales

Recent Industrial Experiments in Cooperation between Poland and Western Europe. Poland is only beginning commercial cooperation with Western countries but the law tends to favor this form of international commerce. Two important problems must be settled: financement for cooperation and the question of credit and customs tariffs.La Pologne n'est qu'au début d'une coopération commerciale avec les pays occidentaux mais la loi tend à favoriser cette forme de commerce international. Les deux problèmes les plus importants à régler sont le financement de la coopération et les questions de crédit et de tarifs douaniers.Tabaczynski E. Expériences récentes en Pologne en matière de coopération avec des industries occidentales. In: Revue de l'Est, vol. 5, 1974, n°2. pp. 35-39

Vogelgrippe, ASP und Co. : Wolf als Überträger von Tierseuchen – kann das sein?

Erst kam der Wolf, dann brach auf der Insel Rügen die Vogelgrippe aus. Kann der Wolf Tierseuchen einschleppen? Dies spricht dafür – und dagegen

ESTIMATION OF PROBABILITY DENSITY AND DISTRIBUTION FUNCTIONS

Abstract not availabl