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The paper is the study of electric resistance of a graphene layer washed by a liquid with different flow rate parameters. Experiments demonstrate that if the fabricated composite (graphene upon a PET/EVA polymeric substrate) is submerged into distilled water, the sample resistance increases by 120 %. Meanwhile, the flow of liquid near the graphene layer decreases this gain in the electric conductivity. The effect offers a general design of a flow rate sensor based on the graphene layer, taken as a sensitive matrix. The study demonstrates that this design of graphene flow sensor (taken for distilled water) exhibits a linear dependency of the sensor resistance on flow rate.

Results of an experimental study and direct numerical modeling of the steady flow in a channel branching region simulating the proximal anastomosis of the femoral artery, are reported. The Reynolds number was Re = 1500, which value corresponds to the maximum blood flow during the period of heart contractions. The ratio of the rates of the liquid flows through the branch and the main channel was a varied parameter. Regularities in the development of the flow structure in the primary channel and in the branch region are revealed, with much attention having been paid to flow separation regions. The occurrence of secondary flows localized within the separation regions has been established. The ranges of the ratio of the flow rates at which flow turbulence signs appear in the mixing layer at the interface between these regions are determined.

Laser radiation is a leading tool in the field of materials processing and design. Recently, the prob-lem of controlled changes in the wetting properties of metals realized by the micro- and nanostructuring of surfaces has been actively investigated. In the pre-sent paper, the influence of the conditions of nano-second laser treatment on the wetting properties of a copper surface in the mode of formation of a ran-domly distributed hierarchical structure is investigat-ed. Special attention is paid to the evolution of the contact angle of wetting over time. The mechanisms of changing the wetting properties over time are con-sidered. It is shown that the overlap of laser spots is more important than the fluence in the beam from the point of view of hydrophobization of the copper surface.

The article presents the results of an experimental study of the cavitation flow around the NACA 0012 series foil in a narrow slit channel with a width of 1.2 mm. The aspect ratio of the streamlined body was 0.02. To identify the main features of the two-phase flow, high-speed visualization was performed using the Photron FASTCAM NOVA S12 camera with a sampling frequency of 20 kHz. The internal structure of cavities was detected. The main frequencies of cavities formation in the flow were determined using digital processing of visualization data. The close location of the channel walls was shown to significantly affect the return flow propagation under the cavity and its separation.

The study is focused on the process of bubble growth inside a intensively evaporating liquid droplet placed on a hot structured surface made of black silicon. Experiments are carried out with volatile fluids FС-72, HFE 7100, ethanol and water. The method using the Schliren-system was developed for study of bubble growth inside a droplet. The contact line speed was measured during microdroplet evaporation, including the case of a growing bubble inside the droplet. The speeds of the contact for droplet evaporation with/without bubble were compared. The contact line instability was found, emerging due to a developed structure of substrate; it facilitates the enlargement of local flows in microregions. This facilitates the heat transfer enhancement.

Microchannel cooling systems are widespread due to their efficiency. In this work boiling of dielectric liquid FC-72 in a flat microchannel with a height of 66 μm and a width of 10 mm was studied. Heating was carried out by a thin-film ITO heater in direct contact with the working liquid. The flow regimes at boiling in a wide range of liquid flow rates were investigated. It is shown that boiling regimes in a flat microchannel differ significantly from the flow regimes in circular and rectangular mini- and microchannels. The dependences of heat flux on the temperature head have been plotted. The dependence of the heat transfer coefficient on the heat flux was investigated for different regimes of the two-phase flow.

This paper presents calculation results on plasma ignition and combustion of coal in the furnace of the PK-39-II boiler at Reftinskaya SDPP. For mathematical modeling of coal combustion in the boiler furnace, a three-dimensional mathematical model Cinar ICE and a software package for physical modeling and calculation of hydro-dynamics, heat and mass transfer and combustion of fuels in the volume of furnace devices were applied used. Cal-culations were performed for two regimes of pulverized coal combustion: the traditional one and using plasma activa-tion of coal combustion. It is shown that the use of plasma-fuel systems (PFS) allows optimization of the coal com-bustion process in the combustion chamber. Three-dimensional modeling of a pulverized coal furnace equipped with a PFS allows one to determine the optimal PFS layout on boilers of thermal power plants.

An experimental study of the specific heat capacity of gadolinium-scandium-gallium and calcium-niobium-gallium garnets widely used in laser technology and microelectronics was carried out by the method of differential scanning calorimetry. New experimental results on the specific isobaric heat capacity in the temperature range of 300 -1270 K were obtained; approximation equations and a table of recommended values for scientific and practical use were developed on their basis. The comparison with the known literature data was carried out. The estimated error of the data obtained was 2-4%.

Combustion of liquid hydrocarbons sprayed with a jet of superheated steam is experimentally studied using n-heptane as an example as a promising method for efficient and environmentally safe combustion. with forced air supply to the gas generation chamber. It is a modernized design of an atmospheric burner with a natural air inflow, studied by the authors earlier, and it allows obtaining additional information about the effect of changing the excess air ratio inside the device on the process of burning liquid fuel in the presence of superheated steam. New data on the environmental and energy characteristics of the burner under study were obtained based on thermocouple measurements, gas analysis of intermediate flame components, measurements of combustion efficiency and harmful emissions in the final combustion products. They were compared with characteristics of the burner with natural air inflow. It was found that formation of carbon monoxide during the combustion of heptane is reduced by 25%, and formation of nitrogen is reduced oxides by 15% with a decrease in the excess air ratio in the combustion chamber from 0.7 to 0.16. At the same time, a burner with a natural air inflow is characterized by a higher flame temperature and a shorter flame length. At that, the level of CO and NO_x emissions in all regimes corresponds to the European standard EN 267. It was determined that the forced air flow does not have a noticeable effect on the heat generated for the studied regimes, and the calorific value of fuel combustion in all cases is close to the higher calorific value of heptane, which indicates the high efficiency of the combustion method under study.

The experimental results on the turbulent flow structure in a lattice matrix cell, which is a region between intersecting ribs on the opposite walls of a flat channel, are presented. The angle between the ribs was 2β = 60º, 90º and 120º; the Reynolds number calculated from the average velocity and hydraulic diameter of the channel was varied in the range Re = (1 - 7)×10⁴. The aerodynamic characteristics of the flow inside a lattice matrix cell placed in a rectangular channel with a cross-section of 20 × 150 mm and a length of 400 mm were measured using a two-component laser Doppler anemometer (LDA). The flow structure was studied in individual cells of 15 × 15 mm, formed by crossing ribs on the opposite channel walls. The complex three-dimensional structure of the flow in the matrix cells and strong turbulence of the flow in the near-wall regions are shown. The installation of ribs leads to a significant increase in hydraulic losses, especially at large crossing angles.