THERMAL INFLUENCES ON THE SURFACE OF THE METALLIC FAIRINGS ABOUT THE PYROTECHNIC ARTICLES UNDER THE CONDITIONS FOR SHOT AND FLIGHT

The pyrotechnic articles of the special designation (illuminating and tracer means, pyrotechnic IR-emitters, tracer compositions, the elements of rocket-space technology and others) on the basis of the condensed mixtures from the powders of the metallic fuels (magnesium, aluminum, titanium, zirconium and other), nitrate-containing oxidizers (sodium nitrate, potassium, strontium, barium, lead and other) and additions of organic matter (paraffin, stearin, naphthalene, antracene, urotropin, iditol, kauchuk SKN-10-1, resin 214 and other), which under the conditions for shot and flight undergo intensive external thermal influences with the supersonic blowout by airflow are examined. Under the action of external heat fluxes the essential heating of the metal housings of articles occurs, early ignition and the development of the combustion of the charges of pyrotechnic mixtures under the conditions of increasing temperatures of heating and external pressures, which leads to the inflammableexplosive destruction of articles. The results of experimental and theoretical studies of the process of heating the surfaces of the metallic fairings of the pyrotechnic articles by external supersonic airflow are represented. Analytical expressions for the heat-flow distributions from the boundary layer along the surface of fairing are obtained and established that it has a maximum, whose location along the surface of fairing for the stream-line conditions of flow is located in the environment of front critical point, and for the turbulent regime of flow this maximum already displaces along the surface of fairing