A theoretical model for the combustion of droplets in supercritical conditions and gas pockets

Sánchez Tarifa, Carlos and Crespo Martínez, Antonio and Fraga, Enrique (1972). A theoretical model for the combustion of droplets in supercritical conditions and gas pockets. In: "International Colloquium on Gasdynamics of Explosions", 12/09/1971-17/09/1971, Marsella, Francia.

Description

Title: A theoretical model for the combustion of droplets in supercritical conditions and gas pockets
Author/s:
  • Sánchez Tarifa, Carlos
  • Crespo Martínez, Antonio
  • Fraga, Enrique
Item Type: Presentation at Congress or Conference (Article)
Event Title: International Colloquium on Gasdynamics of Explosions
Event Dates: 12/09/1971-17/09/1971
Event Location: Marsella, Francia
Title of Book: Astronautical Acta. Proceedings of International Colloquium on Gasdynamics of Explosions,
Date: 1972
Volume: 17
Subjects:
Faculty: E.T.S.I. Aeronáuticos (UPM)
Department: Motopropulsión y Termofluidodinámica [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

Full text

[img]
Preview
PDF - Requires a PDF viewer, such as GSview, Xpdf or Adobe Acrobat Reader
Download (576kB) | Preview

Abstract

Supercritical combustion of droplets is studied by means of a physical model which assumes spherical symmetry, laminar conditions, constant pressure and a zero-thickness flame. Boundary conditions at the infinity state that temperature and composition of the mixture are given and constant. Initial distributions of temperature and mass fractions of the species are given, as well as the initial conditions at the droplet surface. As combustion proceeds, droplet surface is not considered to exist as a physical boundary allowing unrestricted diffusion of species through it. With some additional simplifications for the density and t r ansport coefficients, a numerical solution of the problem is obtained. An analytical solution of the problem is also obtained by means of an asymptotic analysis. This solution applies when the initial temperature of the droplet is small as compared with the temperature of the sourounding atmosphere. It is shown that this is the most impor t ant case from the technological point of view. For this case results show that an apparent droplet exists throughout most of the process, in which its surface is characterized by an abrupt change in temperature and composition of the chemical species. Results show burning rates, combustion times, flame radius and temperature at the droplet center as function of the principal variables of the process. In particular, the square of the apparent droplet radius is a linear function of time as occurs in subcritical combustion. It is shown that combustion times are faster in supercritical conditions than in subcritical conditions with the minimum value existing at critical conditions. A numerical application is carried out for the case of oxygen droplets burning in hydrogen and a comparison is carried out between the theoretical results obtained numerically and analytically as well as with those experimentally obtained.

More information

Item ID: 6459
DC Identifier: http://oa.upm.es/6459/
OAI Identifier: oai:oa.upm.es:6459
Deposited by: Memoria Investigacion
Deposited on: 22 Mar 2011 08:56
Last Modified: 20 Apr 2016 15:44
  • Logo InvestigaM (UPM)
  • Logo GEOUP4
  • Logo Open Access
  • Open Access
  • Logo Sherpa/Romeo
    Check whether the anglo-saxon journal in which you have published an article allows you to also publish it under open access.
  • Logo Dulcinea
    Check whether the spanish journal in which you have published an article allows you to also publish it under open access.
  • Logo de Recolecta
  • Logo del Observatorio I+D+i UPM
  • Logo de OpenCourseWare UPM