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The paper deals with the numerical study of heat and mass transfer in the process of direct evaporation air cooling in the laminar flow of forced convection in a channel between two parallel insulated plates with alternating wet and dry zones along the length. The system of Navier–Stokes equations and equations of energy and steam diffusion are being solved in two-dimensional approximation. At the channel inlet, all thermal gas-dynamic parameters are constant over the cross section, and the channel walls are adiabatic. The studies were carried out with varying number of dry zones (n = 0–16), their relative length (s/l = 0–1) and Reynolds number Re = 50–1000 in the flow of dry air (j₀ = 0) with a constant temperature at the inlet (T₀ = 30 °C). The main attention is paid to optimization analysis of evaporation cell characteristics. It is shown that an increase in the number of alternating steps leads to an increase in the parameters of thermal and humid efficiency. With an increase in Re number and a decrease in the extent of wet areas, the efficiency parameter reduces.

A horizontal water layer of 0.29÷0.44 mm thickness, locally heated from the substrate, is investigated. The value of thermocapillary deformation occurring at local heating is measured by an inverted laser scanning confocal microscope Zeiss LSM 510 Meta. The heater in the form of strip of 0.5-mm width, 40-mm length, and 0.5-mm height made of indium oxide is sputtered on a sapphire substrate. The water temperature from the side of the substrate is measured using the infrared scanner Titanium 570M. We studied in detail the effect of the initial layer thickness and heating power on the value of thermocapillary deformation and temperature field. It is shown that defor-mation increases with an increase in thermal capacity and decrease in the layer thick-ness. Results of numerical simulation are in good qualitative agreement with the measurement results.

The approximate analytic solution of the problem of temperature field in a rectangular plate with an internal temperature-dependent source is obtained by the method of fast expansions. The critical value of a parameter characterizing heat release, which fun-damentally affects the analytic solution form, is found. The maximum solution error is shown to amount to 0.02 at the consideration of the first three terms of the Fourier series in fast expansion. Temperature fields are presented, and an analysis of the influence of the plate sizes and the heat release magnitude on their formation is given. Recommendations on the plate shape choice are given.

The density and the thermal expansion of liquid lithium–lead alloys with Pb content of 83.0 and 84.3 at. % was measured using gamma-ray attenuation technique over the temperature range from liquidus to 1000 K. The density change during solid–liquid phase transition was directly measured for the first time for Li_15.7Pb_84.3 alloy. A comparison of the obtained results with literature data has been carried out.

Thermoelectric materials have attained importance because of the gargantuan energy crisis the world faces today. A thermoelectric material can be used efficiently and frequently, provided, its figure of merit ZT is increased. Also, easy availability, manufacturing, and low cost are the other factors to be considered for a novel ther-moelectric material. A theoretical model is proposed in this paper for the enhancement of the figure of merit of thermoelectric materials.

In the present study, a model for the heating of inert-matrix-hosted metal nano-particles with laser radiation taking into account the melting processes is examined. The calculations were performed using the characteristics of gold and pentaerythritol tetranitrate materials. The kinetic dependences of the temperature and molten-layer thickness on nanoparticle surface were calculated. The main non-dimensional govern-ing parameters of the model were identified. An expression for the maximum thickness of molten layer was obtained. The results can be used in predicting the stability of nonlinear-optics devices with hosted gold nanoparticles, in raising the efficiency of hyperthermia cancer therapy, and in optimizing the optical detonators.

Radiation heat loss is an important type of heat loss in thermal systems. In this work, a numerical study of the transient response of two circular radiation heat shields in-serted between two parallel and circular surfaces of emissivities ε1 and ε2 is pre-sented. The same dimensions have been assumed for the two main radiating surfaces and the two radiation shields. The radiation shields are assumed to have different emissivities on their top (ε3 and ε5) and bottom (ε4 and ε6) surfaces, and both are as-sumed to be different but linear functions of temperature. A specific configuration is investigated in detail to highlight the transient temperature and heat transfer characte-ristics of the system. Some new results for the transient temperature and heat transfer characteristics of the system such as the effect of shield location, shield emissivities, the temperature dependence of shield emissivities, system dimensions, temperatures of the hot and cold surfaces and emissivities of the hot and cold surfaces are pre-sented for future references. It has been observed that increasing the temperature of the first radiation shield by changing a parameter such as surface emissivity or dis-tance between the radiation shield or the temperature of the hot surface, will not nec-essarily decrease the temperature of the second radiation shield.

The paper considers using a differential method for thermal calculation of a furnace with finding the thermal and aerodynamic parameters within the radiation chamber of a tube furnace. The furnace is equipped with acoustic-type burners allocated in three tiers on the lateral walls. The method implies joint numerical solution of 2D radiation transfer equations using the S2-approximation of the discrete ordinate method, of energy equations, flow equations, k-ε turbulence model, and single-stage modeling of gas fuel combustion. Typical results of simulation are presented.

A new approach has been developed to solve the optimization problems of conti-nuous parameters of thermal power plants. It is based on such organization of opti-mization, in which the solution of the system of equations describing thermal power plant, is achieved only at the endpoint of the optimization process. By the example of optimizing the parameters of a coal power unit for ultra-supercritical steam parame-ters, the efficiency of the proposed approach is demonstrated and compared with the previously used one, in which the system of equations was solved at each itera-tion of the optimization process.