Intensive evaporation and boiling of a heterogeneous liquid droplet with an explosive disintegration in high-temperature gas area

Abstract

The using of the high-speed (not less than 10 5 frames per second) video recording tools (Phantom) and the software package (TEMA Automotive) allowed carrying out an experimental research of laws of intensive vaporization with an explosive disintegration of heterogeneous (with a single solid non-transparent inclusion) liquid droplet (by the example of water) in high-temperature (500-800 K) gases (combustion products). Times of the processes under consideration and stages (liquid heat-up, evaporation from an external surface, bubble boiling at internal interfaces, growth of bubble sizes, explosive droplet breakup) were established. Necessary conditions of an explosive vaporization of a heterogeneous droplet were found out. Mechanisms of this process and an influence of properties of liquid and inclusion material on them were determined.

Numerical Investigation of the Main Characteristics of Heat and Mass Transfer while Heating the Heterogeneous Water Droplet in the Hot Gases

“…With further development of the physical setting of the studying process, the physical and mathematical model [3] was extended to assess the impact of flow gap availability on the inert interface R=R 1 on the rate of evaporation of the heterogeneous droplet, as well as the supply of energy to the interface through a solid inclusion and film liquid [4]. Phase transformations at the boundary R=R 1 leads to decrease in characteristic thickness of water film around inclusion.…”

“…Analyzing the results of the numerical investigations of heat and mass transfer and phase transformations in heterogeneous droplets while heating in high-temperature gases by the models developed before [3][4][5] allowed determining the ranges of extreme values of parameters of droplet and gases when the effect of "explosive" droplet disintegration is possible due to intense vaporization at an inert interface. According to the results of numerical simulation, we can make a judgement on a possibility of applying the water with a wide range of values of absorption coefficient k λ without purification and clarification to intensify the phase transformation.…”

“…In conducting the investigations we developed several models that take into account various effects and allow analyzing the influence on heat and mass transfer intensity of a large group of factors (the main mathematical models are presented in the works [3][4][5]). …”

“…Nonlinear nonstationary differential partial equations describing the physical formulations [3][4][5] were solved by finite difference method, the finite-difference analogs of the original differential equations by a locally one-dimensional method and method of variable directions, nonlinear equations by the method of iterations. To solve the one-dimensional difference equations we applied the sweep method using a four-point implicit difference scheme.…”

Effect of the Addition of Petrochemicals onto the Atomization and Ignition of the Coal-Water Slurry Prepared from the Wastes

“…The evaporation of water has strong enough influence on the evolution of the aerosol properties during propagation in free space. The evaporation of water resulting the drying of different flying droplets observed in [18,19]. Problems of droplet fragmentation under extremal thermal conditions are investigated in [20,21].…”