Abstract
The results of research of non-stationary heat exchange in combined packages intended for creation of special water- and heat-resistant protective clothing of firefighters from dangerous and harmful factors during emergency rescue and other urgent works, with participation of non-toxic substances, acid solutions, alkalis, oil and petroleum products, liquid toxic substances, as well as during operation in water with temperature from 0 to 70 °С are presented. The stability of clothing material packs has been investigated as a transient heat exchange process in a multilayer plate with ideal thermal contact at the joints of the layers. The unlimited plate is heated on both sides under different heat exchange conditions according to Newton’s Law, with constant action of the heat source on one of the surfaces of the hot liquid contacting through the waterproof thin surface. Second surface of the plate interacts with external medium, temperature of which varies according to linear law. At solving the equation of non-stationary thermal conductivity with nonlinear transport coefficients, linearization methods are used based on the approximation of nonlinear coefficients, such that nonlinear equations become approximately linear. The entire heat transfer process is divided into a plurality of small-time intervals within which the transfer coefficients are constant. The zonal method of investigation of non-stationary thermal conductivity in clothing packages establishes equations for calculation of temperature, densities of thermal flows, distribution of temperature across thickness of clothing packages. It has been shown that under accepted calculation simplifications, parameter values are well consistent with the experiment. The composition of the clothing package is proposed, which meets the technical requirements of TУ BY 101114857.082-2015 “Personal Protective Kits”.
Highlights
With constant action of the heat source on one of the surfaces of the hot liquid contacting through the waterproof thin surface
Second surface of the plate interacts with external medium, temperature of which varies according to linear law
At solving the equation of non-stationary thermal conductivity with nonlinear transport coefficients, linearization methods are used based on the approximation of nonlinear coefficients, such that nonlinear equations become approximately linear
Summary
Представлены результаты исследования нестационарного теплообмена в комбинированных пакетах, предназначенных для создания специальной водотермостойкой защитной одежды пожарных от опасных и вредных факторов при проведении аварийно-спасательных и других неотложных работ с участием нетоксичных веществ, растворов кислот, щелочей, нефти и нефтепродуктов, жидких токсичных веществ, а также при работе в воде с температурой от 0 до 70 °С. Устойчивость пакетов материалов одежды исследовалась как нестационарный процесс теплообмена в многослойной пластине с идеальным тепловым контактом на стыках слоев. Неограниченная пластина нагревается с обеих сторон при различных условиях теплообмена по закону Ньютона, с постоянным воздействием теплового источника на одну из поверхностей, контактирующей с горячей жидкостью через водонепроницаемую тонкую поверхность. Зональным методом исследования нестационарной теплопроводности в пакетах одежды установлены уравнения для расчета температуры, плотностей тепловых потоков, распределения температуры по толщине пакетов одежды. И. Исследование нестационарного теплообмена в комбинированных пакетах водотермостойкой защитной одежды пожарных / А.
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