Synergetic Effect of Potassium Oxysalts on Combustion and Ignition of Al/CuO Composites

In this study, we studied the synergetic effect of potassium oxysalts on combustion and ignition of nano aluminum (Al) and nano copper oxide (CuO) composites. Potassium periodate (KIO4) and potassium perchlorate (KClO4) are good oxidizers with high oxygen content and strong oxidizability. Different contents of KIO4 and KClO4 were added to nano Al/CuO and the composites were assembled by sonication. When the peak pressure of nano Al/CuO was increased ~5–13 times, the pressurization rate was improved by ~1–3 orders of magnitude, the ignition delay time was shortened by ~0.08 ms–0.52 ms and the reaction completeness was adjustable when 30–70% KIO4 and KClO4 were added into the composites. The reaction of Al/KIO4 and Al/KClO4 at a lower temperature was helpful to ignite the ternary composite. Meanwhile, CuO significantly reduced the peak temperature of oxygen released from the decomposition of KIO4 and KClO4. The synergetic effect of binary oxidizers made the combustion performance of the ternary composites better than that of the binary composites. The present work indicates that KIO4 and KClO4 are promising additives for nano Al/CuO to tune and promote the combustion performance. The ternary composites have potential application in energy devices and combustion apparatus.

Using the group analysis transfer operator in the method of similarity for studying the fuel combustion process in engines

In this paper, we study modelling of the process of combustion of small quantities of a pyrotechnic mixture based on potassium perchlorate and aluminium powder in impulse devices (engines). The analysis of combustion processes includes an introduced general criterion (prime criterion) of similarity composed of Wobbe numbers that are determined for the engine and its model in the course of theoretical studies or experiments. Research data show that the transfer operator in the field of group theory is mostly used for describing the process of combustion of metallized pyrotechnic mixtures.

Salting-in–salting-out effect of potassium salts on the binary liquid water + n-butoxyethanol system with a closed delamination region

The work is devoted to the comparative characteristics of the salting-in –salting-out effect of potassium formate, nitrate and perchlorate on the binary liquid water + n-butoxyethanol system with a closed delamination region in a temperature range of 10–150°C. The introduction of potassium formate or potassium nitrate into the mixtures of the critical composition of the binary water + n-butoxyethanol system leads to a decrease in the LCST (lower critical solution temperature) and an increase in the UCST (upper critical solution temperature) of this system, while the addition of potassium perchlorate leads to an increase in the LCST and a decrease in the UCST. For three ternary systems potassium salt + water + n-butoxyethanol, the distribution coefficients of n-butoxyethanol between the aqueous and organic phases of the monotectic state were calculated for several temperatures. It has been found that the distribution coefficient increases with temperature in each system. It has been established that potassium formate and potassium nitrate have a salting-out effect, the former having a particularly strong one. Potassium perchlorate at low concentrations and relatively low temperatures is characterized by a salting-in effect, which turns into a weak salting-out effect at higher temperatures. The results obtained can be used to develop practical recommendations for carrying out selective extraction of organic solvents and extractive crystallization of salts.

Fuel Ratio and Additives Influence on the Combustion Parameters of Novel Polyurethane-based Flares

Pyrotechnic compositions using polyurethane as binder were designed to maximize the temperature of combustion and the burn rate. The flares consisted in mixtures of potassium perchlorate/Mg-Al alloy/polyurethane/additives. In order to determine the optimum input ratio that conducts to the most appropriate solution in terms of theoretical amount of heat released, specific volume of gaseous products and chemical composition, Explo5� thermochemical software runs were executed. Further, the temperature of combustion and the burn rate were determined by infrared thermography, while the heat of combustion and the specific volume of gases were obtained using an adiabatic calorimeter coupled with a Julius-Peters volumeter. The fuel ratio was varied in the compositions in order to optimize the combustion, and the addition of chlorinated rubber confirmed a significant enhancement in both parameters.