NOVEL TRENDS OF DEVELOPMENT AND PERFECTION THE MODERN HEAT EXCHANGERS

Some actual aspects of advancement the problem of improvement the heat exchange equipment are considered in the paper. First of all the actual items related to middle and high temperature recuperators are discussed with proper up-to — date approaches. The classification of flue gases heat recovery appliances has been proposed along with the statement and analysis of the main characteristics of the recovery plants and option the ways of optimization the mentioned characteristics. The problem of Reynolds analogy (similarity of relative change the heat transfer phenomenon and variation the hydraulic resistance) within the channels of different purpose and of various cross-section supplied with and without the obstacles has been analyzed in application to separate cases of flow along the surfaces equipped with the cavities (dimples) or the convex elements. Thermal Performance Factor (TPF) of the heat exchange process is qualitatively like to Reynolds analogy factor and is highly depended upon rate of heat transfer and of friction factor in conditions of the scheme under consideration for flow over the surface or flow within the channel. The various media has been compared used as a working body in the heat exchanger’s channels: gaseous, liquid and the nanofluids, the last appeared in practice since 2000. Analysis has been carried out on effect of using the secondary energy emitters (SEE) arranged inside the tube channels, on resulting heat flux by heat exchange between outward flow of combustion products and the inner air flow. Bibl. 23, Fig. 6.