Chemical reaction and ignition in mixtures of magnesium and sodium nitrate

The isothermal kinetics and self-heating in binary mixtures of magnesium and sodium nitrate have been studied as a function of temperature and reactant composition. The effects of reduced pressures (down to 10⁻¹ torr) and of replacing the air over the reactants by argon have been examined. Comparative studies of mixtures of sodium nitrate with magnesium oxide, aluminium oxide, and aluminium were also made. From these measurements it is concluded that magnesium is oxidized in the melt by oxygen atoms produced by the decomposition of sodium nitrate and that it is the exothermicity of this reaction which leads to ignition.     

Determination of the optimum orientations for the double-exposure, flat-plate collector and its reflectors

A procedure is presented for determining the optimum angles of tilt for the double exposure flat-plate collector¹ and its various reflectors. Vector analysis has been employed in deriving the various relations.     

Mixing and chemical reaction in an initially non-uniform temperature field

The development of the velocity, temperature and the concentration profiles in the vicinity of the trailing edge is investigated under the boundary layer approximation for an arbitrary initial temperature profile and an arbitrary value of the parameter B for the chemical kinetics.

A series solution is constructed in terms of a system of “universal functions”, from which the initial development of an arbitrary initial temperature profile can be calculated with or without chemical reaction. The first three terms in the series for the temperature have been tabulated previously and are presented here in a diagram.

In the case of no chemical reaction, the analytical results for a given initial temperature distribution predict that the temperature gradient normal to the dividing stream line tends to increase for a limited distance in the downstream direction. This may not be anticipated from the consideration of thermal diffusion alone. Experimental results confirm this qualitative trend. With the three terms in the series solution for the temperature, the agreement between the analytical and the experimental results appears also quite satisfactory.

The analytical results will enable us to calculate the development of the temperature field with chemical reaction. There are as yet no experimental data for comparison.