Abstract
Substantiation of using non-circular plain shaped surfaces to increase the compactness of power plants is presented. The criterion of thermohydraulic compactness is justified, which takes into account the layout and arrangement of heat transfer elements and their thermohydraulic efficiency. To simulate heat movement and transfer processes in elements of power plants, the computational fluid dynamics method is used. Verification is carried out with available literature data, the discrepancy of results does not exceed 2.4 %. For single elliptical and plane-oval shapes, there is a local maximum of efficiency, achieved at the axis ratio of 2.5 for elliptical and 2.75 for plane-oval. Studies of the change of the heat transfer coefficient in the tube bank rows are carried out. For the elliptical tube bank, heat transfer is stabilized from the fifth row. Heat transfer surfaces of circular, elliptical and plane-oval tubes with different combinations of geometric characteristics are considered. It is found that on the basis of elliptical tubes it is possible to reduce the volume of the heat transfer surface and increase the compactness of the entire power plant by 18.3 % compared to circular tubes and 2.4 % compared to flat-oval ones. Dimensionless indices of mass, volume, functional efficiency and service life of the heat exchanger are substantiated, allowing them to be compared as part of various power plants. It is advisable to continue studies of the features of heat transfer processes in close, with the relative longitudinal and transverse pitch ratio less than 1.5, banks of elliptical tubes with an axis ratio of 2.5
Highlights
The efficiency of power plants is increased by improving heat conversion processes in their elements
These applications of elliptical tubes as heat transfer surfaces will make it possible to increase the compactness of the entire power plant up to 18.3 % compared to circular tubes and up to 2.4 % compared to plane-oval ones
The results show the efficiency of using non-circular tubes to increase the compactness of power plants
Summary
The efficiency of power plants is increased by improving heat conversion processes in their elements. A promising direction of increasing compactness due to the intensification of heat transfer processes is the use of “well” streamlined tubes – plane-oval, elliptical, drop-shaped, etc. [4] and optimization of their arrangement in the bank The use of such surfaces would improve the thermohydraulic characteristics of tube banks, which, in turn, would reduce their weight and size parameters and increase compactness. In this regard, studies aimed at substantiating the use of shaped heat exchange surfaces to increase the compactness of power plants can be considered relevant
Published Version
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