Results of a numerical study of the thermal effectiveness of a gas wall screen implemented via gas blowing through cylindrical inclined holes embedded in a transverse trench are reported. The calculations were performed using 3D Reynolds-averaged Navier–Stokes equations, with the flow turbulence being modeled by means of the Reynolds-stress model. Blowing into the trench was compared to the conventional cooling technique using gas blowing without a trench. The film cooling effectiveness with gas injection through circular holes embedded in trench exceeds significantly the effectiveness of blowing without a trench. Such a method of coolant supply into the flow proved to be especially advantageous at high blowing ratios. Due to the formation of vortical structures inside the trench, a more uniform cooling flow in the spanwise direction can be achieved. A comparative analysis is indicative of acceptable qualitative agreement of the experimental and predicted data.

The structure of gas-droplet polydisperse jet was studied experimentally and numerically. Experiments were carried out using the Particle Image Velocimetry/Particle Tracking Velocimetry/Interferometric Particle Imaging methods, which allowed simultaneous measurements of parameters for the average and pulsation carrying and disperse phases. Gas phase turbulence was calculated using the model of Reynolds stresses transfer. Significantly non-isotropic character of velocity pulsation of particles along and across the section of the gas-droplet jet was demonstrated in experiments and calculations. Strong dependence of axial pulsations of disperse phase velocity on the size of its particles is observed.

The flow patterns and heat transfer of a downstream bubbly flow in a sudden pipe expansion are experimentally and numerically studied. Measurements of the bubble size were performed using shadow photography. Fluid phase velocities were measured using a PIV system. The numerical model was employed the Eulerian approach. The set of RANS equations was used for modelling two-phase bubbly flows. The turbulence of the carrier liquid phase was predicted using the Reynolds stress model. The peak of axial and radial fluctuations of the carrier fluid (liquid) velocity in the bubbly flow is observed in the shear layer. The addition of air bubbles resulted in a significant increase in the heat transfer rate (up to 300%). The main enhancement in heat transfer is observed after the point of flow reattachment.

The mathematical model is developed and the swirling two-phase flow behind a sudden tube expansion is simulated numerically using the model of Reynolds stress transport. The gas phase is described by the threedimensional RANS-equations taking into account the back effect of particles on transport processes in gas. To calculate the dispersed phase dynamics in a swirling confined flow, the Euler approach are used. It is found that with an increase in size, the particle are not involved into the separated flow and keep a positive value of the averaged axial velocity along the computational domain. Due to inertia of particle, the zone of reverse flows for the dispersed phase is noticeably smaller than the recirculation zone of gas phase. Performance of the developed mathematical model for description of the swirling two-phase flows in the presence of detachment areas is shown.