A MATHEMATICAL MODEL TO DETERMINE THE COEFFICIENTS OF HEAT TRANSFER THROUGH THE WALL OF OVIOD CROSS-SECTION
We developed a mathematical model for determining the coefficients of heat transfer through a wall of spring-twisted channels made of wires and "ovoid" in its cross-section - a smooth convex closed curve, known as ovoid, of heat exchangers. The rationale for carrying out a theoretical study of heat transfer in such channels is determined by the fact that the geometry of the flow channels are the presence of grooves in their inner side surface that cause circulation of the flow creating turbulence in the wall region, while intensifying the heat exchange in the channel. An important efficiency factor is the determination of heat emission and heat transfer coefficients in convective heat transfer. Calculation of heat transfer in this channel includes determination of the amount of heat transmitted through the wall having an ovoid cross section, per unit of time from a more heated to a less heated agent. The paper provides equations for determining the specific thermal resistances of the more heated and the less heated media, thermal resistance of a wall having complex geometry and total thermal resistance. The theoretical calculations of heat exchange processes are based on the classical principles of determining the coefficients of heat emission and heat transfer, and can be used for a series of spring-twisted channels in pipes of complex configuration. This work is a continuation of the authors' research aimed at creating efficient and small-sized heat exchange equipment, and is targeted at modernizing existing heat exchangers. Based on the results of the studies described in the article, the advantage of the proposed channel for heat exchangers in comparison with existing analogues is also shown. We established that when exchanging smooth-tube heat exchange elements for spring-twisted channels, the heat exchange area will increase, the heat transfer coefficient will increase significantly and the metal capacity of the structure will decrease, and the rate of scaling and scale on the surfaces of the spring-coiled channel will be reduced by about 5 times compared with smooth round tubes. All of the above can be the basis for designing a compact innovative heat exchange equipment of a large unit capacity.