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In the present paper, we discuss various approaches to measurement of velocity fields and velocity fluctuations in incompressible turbulent boundary layer by digital particle flow visualization methods. In particular, performing measurements in the vicinity of streamlined surface is considered. A description of the optical measuring system and methods to seed the flow with tracer particles is presented. Measured data for flow velocity fields and turbulent velocity pulsations in boundary layer on a flat impermeable plate are analyzed. Comparative data illustrating the efficiency of various algorithms for treating PTV images are presented.

A two-dimensional inlet of external compression with the increased flow rate factor at high supersonic velocities is constructed by the method of gasdynamic design. Its feature is that a flow with the initial oblique shock wave and the subsequent centered isentropic compression wave is formed over the external compression ramp of the inlet. These waves interact with one another so that a resulting stronger oblique shock wave and a velocity discontinuity arise in front of the entrance to the inlet internal duct. An example of an inlet configuration with the design flow regime corresponding to the Mach number M_d = 7 is considered. The characteristics of this inlet were obtained in the range of the free-stream Mach numbers M = 4−7 with the use of a Navier-Stokes code for turbulent flow. They are compared with characteristics of an equivalent conventional shocked inlet. As computations have shown, the inlet with the isentropic compression wave has much higher values of flow rate factor ϕ at Mach numbers М < M_d. So, for example, at М = 4 the value ϕ ≈ 0.72 for it is by 33 % higher in comparison with ϕ ≈ 0.54 for the equivalent shocked inlet.

When the stagnation temperature of the combustion chamber or ambient air increases, the specific heats and their ratio do not remain constant any more, and start to vary with this temperature. The gas remains perfect, except, it will be calorically imperfect and thermally perfect. A new generalized form of the Prandtl⎯Meyer function is developed, by adding the effect of variation of this temperature, lower than the threshold of dissociation. The new relation is presented in the form of integral of a complex analytical function having an infinite derivative at the critical temperature. A robust numerical integration quadrature is presented in this context. The classical form of the Prandtl-Meyer function of a perfect gas becomes a particular case of the developed form. The comparison is made with the perfect gas model for aim to present a limit of its application. The application is for air.

In the present work, the regimes of the flow and mixing of fluids in a T-shaped micromixer in the range of the Reynolds numbers from 1 to 1000 are investigated systematically with the aid of numerical modeling. The flow and mixing regimes are shown to alter substantially with increasing Reynolds numbers. Five different flow regimes have been identified in the total. The dependencies of the friction coefficient and mixing efficiency on the Reynolds number are obtained. A sharp increase in the mixing efficiency at a flow transition from the symmetric to asymmetric steady regime is shown. On the other hand, the mixing efficiency slightly drops in the laminar-turbulent transition region. A substantial influence of the slip presence on walls on flow structure in the channel and mixing efficiency has been revealed.

This paper presents physical modeling of thermal tornado under lab conditions. For the tested range of 0÷300 Hz, selective frequencies were discovered which facilitate the tornado decay. Data analysis was comp-lemented by velocity profile measurement using LDV system LD-05M. The results on velocity pulsation at selected points were recalculated into coefficient of correlation between velocities and function cos(2π f Δt_i) describing the acoustic oscillations. In the theoretical part of this paper, we present solution of dispersive equation of Euler's model and resulting boundary of stability for tornado existence. Satisfactory agreement between experiment and calculation has been observed.

The authors have formulated the problem of joint optimization of pressure and temperature of combustion products before gas turbine, profiles of nozzle and rotor blades of gas turbine, and cooling air flow rates through nozzle and rotor blades. The article offers an original approach to optimization of profiles of gas turbine blades where the optimized profiles are presented as linear combinations of preliminarily formed basic profiles. The given examples relate to optimization of the gas turbine unit on the criterion of power efficiency at preliminary heat removal from air flows supplied for the air-gas channel cooling and without such removal.

Numerical technique was developed for simulation of cavitating flows through the flow passage of a hydraulic turbine. The technique is based on solution of steady 3D Navier-Stokes equations with a liquid phase transfer equation. The approch for setting boundary conditions meeting the requirements of cavitation testing standard was suggested. Four different models of evaporation and condensation were compared. Numerical simulations for turbines of different specific speed were compared with experiment.

It was confirmed in experiments that during contact between cool and hot liquids, the lower subcooling of the cool liquid below the saturation temperature changes the characteristics of a vapor layer covering the fragments of hot liquid. This factor also decreases the probability of spontaneous direct contact between two kinds of liquid, explosive incipience of the cool liquid, and pressure pulse generation (the latter triggers fine fragmentation of hot coolant and vapor explosion). The mechanism that describes this trend in vapor layer behavior has been described.

Prospective cyclic hydrocarbon combustion processes those differ by the type of chemisorbent are considered. In the carbonate cycle for СО₂ isolation from flue gases a high-temperature solid regenerable СО₂ chemisorbent is used. In the oxygen cycle, solid oxygen chemisorbent is used that is restored via contacting with fuel and oxidized when exposed to air. A common feature of such processes consists in solid-state reactions of binding and releasing the products or reactants at different stages of the process. Requirements for chemisorbents are determined concerning cyclic processes. Various factors affecting the efficiency of their use are considered, literature data concerning the efficiency of proposed СО₂ concentration cycles are presented.

Hemosorption (purifying the blood outside an organism) and enterosorption (detoxification of an organism through the gastrointestinal tract) are the most promising methods of the sorptional medicine. As far as the adsorption of toxic substances with different molecular mass and nature is concerned, carbon sorbents are of interest to meet the requirements of medicine. Sorbents of different nature and structure are described. Methods for controlling the adsorption activity of the sorbent are indicated. A particular attention is paid to the development of selective sorbents for using in sorptional medicine and proteomics.