Особенности динамики струйного потока, генерируемого при поверхностном кипении жидкости на лазерном нагревателе

It was experimentally found that hot submerged jets appeared at laser induced nucleation boiling near the tip optical fiber placed in water exponentially decrease the velocity with the increasing of laser power (heat flux). This result was obtained for closed cylindrical cuvette where hot jets collided with walls slipped the cuvette boundary and transfer the heat. Obtained result is necessary to take into account at precise laser induced surface cleaning inside the closed volumes, for development of medical technologies of laser therapy of pathologically changed vessels, cysts, and for other applications.

Самопроизвольное (спонтанное) вскипание затопленных струй, генерируемых при коллапсе паровых пузырьков

The effect of secondary spontaneous boiling of submerged jets formed during the collapse of vapor bubbles during the bulk boiling of water subcooled to the saturation temperature at the end of a laser optical fiber is experimentally discovered.

Mathematical modeling of the kinematics of chemical droplets when pulverizing with a sprayer based on a new two-fluid turbulent model

A mathematical modeling and numerical solution of the motion of the droplets of chemical reagents outflowing from the pneumatic sprayer are developed in the article. A new efficient two-fluid turbulence model is used to simulate turbulent flow. The mass fraction of liquid in the gas stream is considered small. Therefore, the effect of the liquid phase on the dynamics of air is ignored. The "parabolize" system of hydrodynamic equations is solved for the gas flow. For this, a marching method of integrating equations is used. The Lagrange approach is used to find the droplet trajectories. It is shown that the new turbulence model can be successfully applied to study two-phase submerged jets. The solutions obtained made it possible to determine a pattern of the field treatment by chemical reagents and define the sprayer's optimal parameters.

On the Consideration of Diffusive Fluxes Within High-Pressure Injections

Mixing characteristics of supercritical injection studies were analyzed with regard to the necessity to include diffusive fluxes. Therefore, speed of sound data from mixing jets were investigated using an adiabatic mixing model and compared to an analytic solution. In this work, we show that the generalized application of the adiabatic mixing model may become inappropriate for subsonic submerged jets at high-pressure conditions. Two cases are discussed where thermal and concentration driven fluxes are seen to have significant influence. To which extent the adiabatic mixing model is valid depends on the relative importance of local diffusive fluxes, namely Fourier, Fick and Dufour diffusion. This is inter alia influenced by different time and length scales. The experimental data from a high-pressure n-hexane/nitrogen jet injection were investigated numerically. Finally, based on recent numerical findings, the plausibility of different thermodynamic mixing models for binary mixtures under high pressure conditions is analyzed.