The present status of research on the production of foam-glass from siliceous rock by the one-step scheme is examined. The main technological principles of the experimental production of granular foam-glass based on diatomites are formulated. The production process is described and the main properties of the 5 -10 mm fraction as compared with the normative requirements are presented.The simplification and cost reduction of the technology of granular foam-glass, which is an environmentally clean material in high demand, are problems of current interest [1 -5]. The trends in this field consist of the following.The process of obtaining foam-glass in the form of granules is the most easily implementable technology for producing foam-glass in the form of a building product ready for use.In the heat-treatment process the cross section of a granule is subject to smaller temperature gradients than foamglass blocks, which simplifies the foaming and annealing processes. A tunnel furnace many meters long and a stock of special molds are not required. Granular foam-glass has a wide range of applications, starting from heat-insulation fills and fillers in light concretes to thermal stabilization of the foundations of engineered structures. It is especially important to obtain fine granular foam-glass for developing new materials in order to impart special properties to them.
The work proposes test one-dimensional models of heat and mass transfer in heat pipes during cooling of active phased antenna arrays, which can be used in processing the test results of flat heat pipes in order to determine their performance characteristics and identify the parameters required for modeling in a more complex setting (for example, in flat and taking into account the presence of several localized sources of heat supply). To take into account the influence of the heat release power on the equilibrium temperature inside the heat pipe, the model has been added to take into account the dependence of the steam saturation temperature on the pressure, which is realized inside the steam pipeline when the heat pipe is heated. Numerous calculations carried out made it possible to refine the mathematical model. In particular, a significant effect on the temperature distribution along the heat pipe is shown, taking into account the dependence of the steam saturation temperature on the pressure in the parawire. It is shown that the introduction of standard functions for the characteristics of the coolant (water) in the liquid and vapor state, as well as taking into account the capillary pressure on temperature, makes it possible to refine the resulting solution.
The article provides an algorithm for calculating the limiting characteristics of heat pipes for cooling active phased antenna arrays at a given saturation temperature. The maximum transmitted power is determined taking into account the limitations of the heat pipes operation by the capillary limit, by boiling (transition to film boiling, boiling limit), by the sonic limit at which the speed of steam reaches the speed of sound (sonic limit), by the entrainment of droplets liquid coolant from the surface of the wick with a counter flow of steam (entertainment limit) and viscous limit, which is realized at low temperatures (viscous limit). It is shown that an increase in the thickness of the wick and its porosity may be necessary to increase the capillary limit of heat pipes, while an increase in the thickness of the wick increases the thermal resistance of the tube and, accordingly, can lead to overheating of the cooled elements. Based on the above algorithm, design calculations for two types of heat pipes have been carried out. The dependences of various limits of the heat pipe on the operating temperature are plotted. Based on the above algorithm, calculations were performed for two types of heat pipes.
In this paper, a mathematical model of a multilayer panel made of nanomodified carbon fiber reinforced plastic with asymmetric packing is proposed. The introduction of nanosized particles into the composition of the composite or its components (fiber or binder) allows not only to increase its physical and mechanical properties, but also to improve the picture of the residual stress-strain state. The paper investigates the effect of nanomodification of carbon fiber reinforced plastic on the residual stress-strain state after molding using numerical and analytical methods. Numerous results of computational experiments have been obtained. The results of numerical and analytical modeling are compared with experimental data. Conclusions are drawn about the possibility of reducing the residual stress-strain state in structures with asymmetric reinforcement schemes when using a matrix containing carbon nanoparticles. A mathematical model of a multilayer panel made of nano-modified carbon fiber with asymmetric packing has been built. Investigation of the residual stress-strain state of structural elements made of carbon fiber reinforced plastic made it possible to reveal the possibility of reducing the residual stress-strain state and leash in structures with asymmetric reinforcement schemes when using a matrix containing carbon nanoparticles.
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