In trod uctionRecently, in connection with constantly growing prices of energy resources vital importance is imparted to the efficiency of production and consumption of the energy, as well as to energy saving techniques. A most frequent solution in this sphere is the installation of heat exchange skids (utilizer boilers, recuperators, waste gas heaters). Naturally, the requirements to the heat exchange equipment are similar to those of the main equipment: they are high efficiency and reliability, failure freedom etc.For fluid heat exchangers the power consumption for overcoming of friction and resistance (circulation flow energy) occuring during the fuid flow through the heat exchanger are generally negligible as compared with the respective calorific transfer. Accordingly, the influence of the consumed power for compensation of friction and resistance are rarely a crucial factor. But as for gaseous media heat exchangers the consumption of the mechanical energy for friction overcoming can rather easily reach values comparable with the value of the calorific transfer. Thereby it is necessary to remember that in the majority of industrial plants the mechanical energy "costs" are by several times (usually 3-5) more "expensive" than the equivalent thermal energy. 10.7463/0113.0532996 2It is easy to demonstrate that for the majority of channel shapes used to construct heat exchange surfaces the specific thermal load of the surface can be increased by the velocity increase of the coolant and the thermal load change is proportional to the velocity change raised to power close to 1.The energy input for the overcoming friction is also increased along with the growth of the flow velocity but it is generally changed proportionally to second power of the velocity. This is the characteristic feature of the correlation of the parameters of the calorific load and the friction (power for coolant pumping) which determines many features of heat exchangers of different classes. To compare surfaces with various ways of the heat exchange intensification a correlation is introduced between the efficiency growth of the heat transfer (correlation of Nusselt number on a surface with heat transfer intensifiers with Nusselt number on a smooth surface) and the resistance growth with the introduction of transfer intensifiers. This correlation is called Reynolds analogy with the following

Приведены принципы работы устройства газодинамического энергоразделения газа (трубы Леонтьева). Выполнен анализ возможных путей повышения эффективности его работы. Показано, что для газов с числом Прандтля порядка 0,7 увеличение количества переданной теплоты возможно за счет использования: вихревых механизмов интенси-фикации теплообмена и влияния сконденсированной фазы на интенсификацию тепло-обмена. Модернизирована методика расчета данного класса устройств, позволившая учесть влияние сконденсированной фазы на интенсификацию теплообмена. При этом учитывается не только теплота фазовых переходов в процессе конденсации, но и до-полнительное влияние на коэффициент восстановления температуры на стенке сверх-звукового канала слабых скачков уплотнения, вызванных течением сконденсированной фазы. По данным экспериментальных исследований на природном газе выполнена ве-рификация модернизированной методики расчета. В результате численных исследова-ний установлено, что при наличии конденсирующихся компонентов в сверхзвуковом потоке рабочего тела эффективность устройства газодинамического энергоразделения может быть повышена в 1,3-1,7 раза без значительного роста потерь полного давления в сверхзвуковом канале устройства энергоразделения.Ключевые слова: энергоразделение, число Прандтля, коэффициент восстановления температуры, труба Леонтьева, интенсификация теплообмена, природный газ, кон-денсация.The working principles of a gas-dynamic energy separation device known as the Leontiev tube are examined. Possible ways to improve the efficiency of the device are analyzed. It is shown that for gases with the values of the Prandtl number of around 0.7, it is possible to increase the amount of transferred heat by utilizing vortex heat transfer enhancement mechanisms and by using the influence of the condensed phase on the heat-transfer intensification. The existing methods for calculating this class of devices were refined to account for the condensed phase influence on the heat-transfer intensification. The refined methods take into account not only the heat of the phase change during condensation but also the effect of Mach shocks generated by the condensed phase flow on the temperature recovery factor on the wall of the supersonic flow channel. The calculation methods were verified against the experimental results obtained with natural gas. The results of numerical -------* Работа выполнена при поддержке Российского научного фонда (грант РНФ 14-19-00699).

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