Schegolev

pp. 217-237

The paper investigates an influence of helium fraction on the Prandtl number value for various gas mixtures. It is shown that a low value of the Prandtl number allows us to raise efficiency of gasdynamic energy separation in Leontyev's tube. The paper conducts a numerical research of the influence of gas mixture composition on the Prandtl number value, and verifies the calculation procedure, using the known experimental data and calculation results of other authors. It is shown that there are binary mixtures of the "light" and "heavy" gases, possessing abnormally low value of the Prandtl number, and the used calculation procedure allows correct calculation of their thermo-physical properties.

The article presents a research problem of heat and hydraulic characteristics of high-compact plate-fin heat-exchange surfaces. These heat-exchange surfaces are widely used in aerospace applications, space and renewable power generation. The experimental facility and measurement routine are described. The experimental facility has a closed loop, which allows to use it for different working mediums (air, mixtures of inert gases etc.). A transient method of heat research was used. The experimental data for BMSTU №9 surface in the range of Reynolds numbers from 100 to 700 for air is given in the article. Obtained experimental data was compared with the data of Kays and London for surface №104.

The non-stationary method with the usage of thermochromic liquid crystals is one of the modern approaches to the heat transfer characteristics evaluation. It allows calculating the local heat transfer coefficients distribution in the inner channels of turbomachine cooling systems. The structural scheme and technical implementation of experimental stand are shown. The process of data collection and processing for computing of local heat transfer coefficients was described.