Ключевые слова: boundary conditions

Influence of heat resistance of the enclosing structures of a heated room on the choice of the type and location of the heating device

https://doi.org/10.58224/2618-7183-2026-9-1-5
Аннотация
The article examines the influence of heat resistance of enclosing structures on the choice of type and location of heating devices in the room. The main attention is paid to the relationship between the thermal characteristics of fences and the method of heat transfer of heating devices. The paper considers two main types of heat transfer: convective and radiative. It is shown that at low thermal stability of structures, it is advisable to use devices with a predominant convective heat transfer (convectors, panel radiators), and at high – with radiation (radiators, underfloor heating, infrared heaters). A mathematical model of spatial non-stationary heat transfer in a heated room is developed, taking into account various thermophysical characteristics of enclosing structures and the type of heat release sources. The study of the amplitude of fluctuations in the temperature of air and internal surfaces, depending on the type of heating device, is carried out. The practical significance of the work is the development of scientifically based recommendations for the selection and placement of heating devices, taking into account the heat resistance of enclosing structures. The results of laboratory tests confirm the theoretical conclusions and demonstrate the nature of the temperature distribution in the room under various heat exchange conditions. The results of the study show that the correct choice of the type and location of the heating device allows you to ensure uniform heating of the room, minimize energy consumption for heating and create comfortable microclimate conditions.
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Heat and mass transfer in concrete mixtures during transportaion along the route «Manufacturer of liquid – phase solution – consumer of solid-phase concrete»

https://doi.org/10.58224/2618-7183-2025-8-6-6
Аннотация
The durability of concrete is a critical operational parameter that directly determines the service life of concrete structures. Achieving a concrete mixture with specified rheological and strength properties is a vital technological stage, as the quality of the initial material governs the load-bearing capacity of the final reinforced concrete elements. In the technological process, the transformation of concrete mixture components into a liquid non-Newtonian system with distinct rheological characteristics, followed by solidification into a structured composition, depends significantly on the variability of physico-mechanical, thermophysical, and structural-mechanical properties of both individual components and the overall mixture.
Developing comprehensive mathematical models that describe the entire technological cycle—from production to placement—poses a multifactorial challenge aimed at ensuring the design durability of construction structures. Particular emphasis is placed on modeling heat and mass transfer processes within heterogeneous concrete systems, as these non-stationary external influences critically affect the operational characteristics of the final material. Transport and hardening parameters heavily influence structural transformations within the cement stone, ultimately impacting strength and deformation properties. Effective resolution of this problem necessitates modern numerical modeling techniques that incorporate the rheological behavior of concrete mixtures and hydration kinetics.
The proposed mathematical and algorithmic framework underpins efforts to minimize concrete structure degradation by simulating rheological parameters during transportation and placement. A principal achievement is the creation of heat and mass transfer analysis algorithms that integrate predictive models with real-time monitoring data, laying a methodological foundation for future technological process control systems. The solutions further include optimization of logistical parameters under varying temperature and humidity conditions and the establishment of criteria to assess the structural homogeneity of concrete mixtures.
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