Shall-and-tube heat exchangers based on the bundles with in-line or staggered arrangements have been widely used in industry and power engineering. A large number of theoretical and experimental works are devoted to study of hydrodynamic and heat transfer processes in such bundles. In that, works the basic studies of heat and mass transfer for these bundles are found. However, heat exchangers of this type can have big dimensions and mass. One of the ways to improve the weight and dimensions of the shell-and-tube heat exchangers is to use compact arrangement of tube bundles. A new design of heat exchanger is proposed, in which there are no gaps between adjacent tubes that touch each other. Different geometry of these tube bundles with displacement of adjacent tubes in the direction of transverse to the flow is considered. Numerical modelling and experimental investigations of hydrodynamic, heat and mass transfer processes in such tube bundles has been carried out. The distribution of velocities, temperatures, and pressure in inter-tube channels have been obtained.

Numerical modeling of heat and hydrodynamics processes in the channels of compact small diameter tube bundles with different transverse shifted arrangement is carried out. The fields of velocities, temperatures, and pressures in the tube bundle channels were obtained, and their influence on heat transfer conditions and hydraulic losses were analyzed. The calculation of the thermohydraulic efficiency for different constructions of the tube bundles had been carried out, and their results with data of well-known tube bundles of different geometry are compared.

Accumulation of thermal energy is produced with the aim of storing at certain times, when there is an overabundance of this energy and its further use in other periods of time when there is a deficit thermal energy. Thermal energy storage may be carried out under heating of any material (water, solid materials etc.) or by using the phase or chemical transformation of the material (melting and crystallization processes, direct and reverse chemical reaction). Thermal accumulators with phase or chemical transformations are allowed to concentrate a large amount of energy in a relatively small volume of accumulating material. In this paper an experimental study and numerical modeling of heat and mass transfer in the heat accumulator during phase transformations of the accumulating material are presented. The experimental plant consists of a chamber filled with paraffin. In experimental studies, the changes of the temperature distribution in heat accumulating material and tube bundles have investigated. Numerical simulation of melting and solidification of heat accumulating material during the heated and cooled of tube bundles were performed. As the results of research, the basic laws of melting and crystallization processes in heat accumulator during phase transformations of heat accumulating material were determined.

Tube bundles with cross flow heat carrier chart are widely used in many power systems due to their relatively simple design, low cost, low pressure drops, high efficiency etc. In order to exploitation these tube bundles in dirty and aggressive applications, protective coatings can be applied to the heat transfer surface to enhance effectiveness and minimize pollutant deposits. Protective coatings generally using for improving wear resistance, corrosion resistance, thermal conductivity to heat transfer surface and thermal insulation of frame surfaces of heat exchangers. In this work physico-mechanical and thermophysical properties of heat conduct coating materials forheat transfer surface are investigated. Experimental and numerical investigations of hydrodynamics andheat transfer processes for compact small diameter tube bundles coated by epoxy composite with high thermal conductivity nanofillers are presented. Experimental investigations of investigated tube bundles were carried out in open circuit section type wind tunnel of subsonic speeds.

The work reports on the experimental research on the determination of the number of Nusselt concerning the compact bundle of small diameter smooth tubes. Having an inline arrangement, it lacks the gapsbetween adjacent tubes of longitudinal rows. In comparison to the traditional inline arrangement, this type of bundle is noticed to have significant advantages such as an increased coefficient of heat transfer and reduced aerodynamic resistance of the tube bundle. At the same time, the use of the compact bundle of small diameter smooth tubes leads to the beneficial reduction of the size and mass of heat exchangers of the shell–and–tubes type. Several series of experimental investigations uponthe aforementioned kind of bundle in open circuit section type wind tunnel of subsonic speeds applyingvarious hydrodynamic flow conditions are ran. As a result of these investigations, the correlations and definite dependences of the Nusselt numbers Nu and Euler numbers Eu on the Reynolds number Re of tube bundle were revealed.