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This paper presents a method of estimating all three global kinetic parameters, A (preexponential factor), E (energy of activation), and n (reaction order), from the results of a single dynamic (nonisothermal) thermogravimetry (TG) run on a propellant sample. The procedure will also show how satisfactorily pyrolysis of the propellant can be represented by the simple relation of Eq. 4 (d{alpha}/dT = (1{minus}{alpha}){sup n}(A/{phi})e{sup {minus}E/RT}) with constant values of A, E, and n where {alpha} = fractional reaction, T = temperature, {phi} = programmed increase in T, and R = universal gas constant.

This paper examines the relative flammability hazard presented by the fuel tank headspace vapours of various alcohol-gasoline blends, including methanol (MlOO), ethanol (ElOO), winter gasoline, summer gasoline and winter and summer blends of M85, E85 and E10. Ignition tests were conducted to establish flammability limits for each of the fuels. Measured limits were compared to those predicted by the RMC multicomponent fuel volatility model and conclusions were drawn as to the comparative hazards of the fuels studied. The model was also used to examine the effect of fuel tank fill level on the flammability limits of the respective blends. The results show the tendency of the flammability limits both to broaden and shift to warmer temperatures with decreasing fill level or increasing alcohol content.

The method presented allows real fuel behavior to be described with simple explicit equations. Instantaneous values of the properties of both phases of a vaporizing fuel can be computed.

An investigation of recirculating characteristics of circular turbulent confined jets with large density variations is presented. This numerical study aims at testing analytical predictions associated with the Craya-Curtet number. It investigates also its effect on the dynamic field and recirculation. It appears that for different density (He-air, CO2-air) and geometry ratios, the non-isothermal Craya-Curtet number [1] is not sufficient to describe the flow pattern or predict its recirculation. Depending on the momentum, aspect and density ratios of the flow, the centre of the recirculating flow (the eye) tends to reach the initial (non-self-preserving) region of the jet and influences the development of the jet. As a consequence, predictions are not in agreement with theory. The reason is that initial conditions do not satisfy the hypothesis used in the prediction of recirculation theory. Calculations are performed in three configurations: CO2, air and He. These configurations are fully developed pipe jets evolving in an air secondary turbulent flow. Validations are performed using experimental data [2] obtained in similar configurations for the three gases.

The physical and chemical processes that occur typically in and around an oil-sand fragment are examined experimentally when the fragment is suddenly introduced into a hot, low-uniform-velocity, gaseous oxidizing stream. With increasing temperature, three regimes were identified in the behavior of the fragments: volatilization, slow heterogeneous combustion, and combustion of the fuel as a diffusion flame. An expression for the oil mass removal with time is then suggested on the basis of a Fourier number for the fragment. Moreover, it is shown that autoignition occurred within the issuing volatiles at temperatures above 520° C.

Experiments have been performed on laminar diffusion flames of mixtures of water and hydrocarbon vapor of different compositions with the mole fractions of water ranging up to about 0.9. The soot emission from the flame decreased steadily with an increase in water concentration; concurrently, there was a progressive decrease in the maximum flame temperature. It is concluded that the reduction in sooting tendency of diffusion flames with water addition is mainly a thermal effect.