Combustion Process. Unconventional Conditions

This paper firstly sets up a six-thermal current model through further developing numerical simulation of three-dimensional combustion process under microgravity. Since the spread of flame in microgravity has the feature of coupling, which is overcome by using the method of additional source in this paper. At the same time in the diffusion flame simulation model, the SCRS is used to simplify the equation group of differential, which simplifies the process of solving of the normal FORTRAN language program. By using the enhanced FORTRAN Language program to simulate combustion progress in microgravity, a better simulation result is obtained.On the basis of simple diffusion flame spread model, the author establishes a three-dimensional microgravity numerical simulation model of flame spreading along the vertical board. The model details the control equation of component in order to further close in upon the real process. Through calculating with these two models, the author finds out that the function of diffusion plays the leading role in the progress of flame spread because of the disappear of the function of buoyancy. The simulation of temperature field and velocity field proves "the spray of surface fuel" effect, the rule of isotropy of velocity and the symmetrical and even distribution of temperature.The author also establishes a three-dimensional numerical simulation model of the candle to test three assumptions of why the candle burns with blue hemisphere flame under the environment of microgravity which has been brought forward by some expert. And the result of calculation indicates that the maximum temperature of the flame of the candle is lower than the minimum temperature producing black fume in microgravity and without strong convection. It also proves the statement that the candle's highest temperature in microgravity is lower than that in normal gravity.The use of candle experiment facilities equipped in the parabolic flight of zero-G aircraft is taken to observe and record the condition ofclassical hemisphere candle flame. Then the author makes an analysis of the pictures observed. For it can only get scattered temperature value in microgravity environment from the experiment, the author applies error theory and neural network theory to get a smooth and continuous curve of flame temperature value in different gravity situation so that the temperature of flame can be analyzed and compared.