Numerical Study of Heat Exchange Processes in Channels of Small-Sized Panel-Radiant Heating Systems of Premises

Abstract

The article presents the results of numerical 3D modeling of free-convective heat transfer processes in the channels of one of the main variants of a panel-radiant heating system of premises. The features of hydrodynamics and heat transfer in vertical channels of rectangular cross-section with the presence of horizontally arranged pipes and ribs mounted vertically on them, and various conditions of heat transfer on the surfaces of the adiabatic wall and radiation shield bounding the channels are revealed. The spatial distributions of temperature and air flow velocity in the system for two possible heat transfer modes are determined. The modes are implemented in different ranges of variation of the modified Rayleigh number Ra and correspond to heat transfer modes with a pre-existing thermal conductivity (Ra ≤ 10) and convective (Ra ≥ 100) heat transfer mechanism. It is shown that there is a limitation of the mass flow rate of the free-convective air flow through the channels of the system. It is established that the average heat transfer coefficient in the channel of the panel-radiant system is a monotonously increasing function of the distance between the edges of the system. The criterion dependences of the Reynolds and Nussellt numbers on the Rayleigh number and on the main design parameters of the system are proposed. A formula has been obtained for calculating the power of specific (per unit length) heat removal from the heating surfaces of the internal elements of the baseboard system. It is proved that the specific heat removal power takes on a maximum value at a certain value of the intercostal gap, at which a transient heat exchange regime should take place. Correlations between the capacities of convective and radiative heat fluxes generated in the considered heat exchange system have been established. The calculated and existing experimental data on the specific heat removal capacity are compared and their satisfactory agreement is indicated

The work was partially supported under the government task by the Ministry of Science and Higher Education of the Russian Federation (project no. FSFN-2024-0022)

Please cite this article in English as:

Grishin Yu.M., Khandramay N.A. Numerical study of heat exchange processes in channels of small-sized panel-radiant heating systems of premises. Herald of the Bauman Moscow State Technical University, Series Natural Sciences, 2025, no. 1 (118), pp. 100--118 (in Russ.). EDN: DVSTPB

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