Engineering topics

Bellan, Josette

Publications and source records attributed to Bellan, Josette.

62 records · Page 4

NASA NTRS1990

Electrostatic Dispersion Of Drops In Clusters

Electrical charging speeds evaporation. Report presents theoretical study of evaporation and dispersion of electrostatically charged clusters of drops in liquid fuel sprays. Represents extension of studies described in article, "More About Evaporation of Drops in Clusters" (NPO-17594). Undertaken in effort to learn how electrostatic atomization used to disperse fuel better in order to reduce formation of soot in diesel engines and other power and combustion systems.

Bellan, Josette↗

NASA NTRS1990

Behavior Of Evaporating Liquid Drops In Clusters

Report presents critical analysis of methods, developed for calculating behavior of evaporating liquid drops in dense and dilute clusters. Essential to understanding variety of physical and chemical phenomena occurring in combustion of sprayed fuels and in sprays used in agriculture, food industry, and painting. Presents insights on important aspects of two-phase flow.

Bellan, Josette↗

NASA NTRS1990

Convective Evaporation Of Clusters Of Drops

Report presents results of continuing theoretical research in behaviors of sprayed liquid fuels at temperatures characteristic of furnaces. Two earlier papers arising from this investigation described in "Evaporation of Dense Fuel Sprays" (NPO-16954).

Bellan, Josette↗

NASA NTRS1989

Turbulence And Evaporation In Clusters Of Drops

Report presents theoretical model of evaporation of cluster of drops of single-component liquid fuel in and of processes of exchange between cluster and gas surrounding it. Formulation of model has three components: description of conservation of mass, molecular species, and enthalpy in sphere of influence of each drop; description of conservation of mass, molecular species, and enthalpy in cluster volume; description of convective effects by use of differential equations expressing conservation of momentum for gases and drops. Results obtained from analysis show turbulence enhances evaporation and controlling factor in evaporation of very dense clusters. Practical implication of findings evaporation of fuel controlled more readily near fuel injector than farther along combustor.

Bellan, Josette↗

NASA NTRS1989

Effects Of Turbulence On Ignition

Report presents theoretical study of effects of turbulence on ignition of drops of single-component liquid fuel. Closely related to article, "Turbulence and Evaporation in Clusters of Drops" (NPO-17323). Uses theoretical model for evaporation and model for ignition developed previously. Radial velocity, va, of gas at surface of sphere of influence taken as algebraic combination of rate of evaporation and speed with which radius changes. Weighting factors of algebraic combination are such that in dilute spray, all new vapor coming from drops trapped in cluster, whereas in dense spray where evaporation strong, maximum new vapor escapes to ambient.

Bellan, Josette↗

NASA NTRS1989

Model Of Turbulent Gas Eddies Containing Drops

Report proposes development of mathematical model of turbulent eddy of gas containing drops of liquid fuel. Closely related to those described in "Turbulence and Evaporation in Clusters of Drops" (NPO-17323) and "Effects of Turbulence on Ignition" (NPO-17335). Goal to initiate development of theory of interactions of several eddies containing drops during evaporation, ignition, and combustion of liquid fuels injected into combustors. Numerical results of analysis given as plot of nondimensionalized evaporation time versus initial ratio of air mass to fuel mass.

Bellan, Josette↗

NASA NTRS1988

Evaporation And Ignition Of Dense Fuel Sprays

Simple theoretical model makes useful predictions of trends. Pair of reports presents theoretical model of evaporation and ignition of sprayed liquid fuel. Developed as part of research in combustion of oil and liquid fuels derived from coal, tar sand, and shale in furnace. Work eventually contributes to increase efficiency of combustion and decrease pollution generated by burning of such fuels.

Bellan, Josette↗

NASA NTRS1987

Convective Evaporation Of Sprayed Liquid

Theoretical model developed to analyze behavior of both dense and dilute clusters of evaporating liquid drops in gas flows. Particularly useful in search for methods of controlling evaporation, ignition, and combustion of fuel sprays.

Bellan, Josette↗