Free convective of a linear heterogeneous liquid in a square cavity at side heating

In this work the problem of free convection of the Newtonian poorly stratified liquid in the cell warmed up from left and cooled from right with the heat-insulated horizontal boarders is presented. Liquid with small concentration of salt and initial linear stratification on cell height is considered. The model of double diffusion in a Boussinesq approximation is applied to model the process. The problem is solved both in two - and three-dimensional statement by means of a control volume method and a SIMPLE algorithm. It is shown that vortex structures at the layered mode of convection have quasi-two-dimensional character.

Laboratory and Computational Fluid Dynamics Investigation of Homogenization in a Tank Stirred by External Pump

The scope of this study was to investigate the homogenization of a two-layer stratified liquid in a tank where liquid stirring was achieved by carrying out external recirculation. Furthermore, the aim of the research was to observe the effect of the height of the outlet during the time of mixing one. The experimental fluid was two-layer, density stratified liquid. From the perspective of homogeneity, the effect of the height of the outlet was investigated in laboratory. Moreover, the experimental device was modeled in CFD. In simulation examination, laminar - and k-ε-model were used, and the influence of the outlet position was observed. The difference was remarkable in the first part of the measurement caused by the presence of sharp concentration variation in the tank. After the operating time, the expected homogeneity was fulfilled at the outlet in all cases. Regarding of CFD research, the results suggest that the laminar model is more effective to describe the concentration changes at the sampling point in the tank investigated.

THE IMPACT OF LIQUEFIED NATURAL GAS COMPOSITION AND TECHNOLOGICAL CHARACTERISTICS OF THE STARTING STORAGE OF THE EQUIPMENT AT THE TIME OF OCCURRENCE OF THE PHENOMENON OF ROLLOVER

Objectives. Ways to prevent the onset of rollover in the liquefied natural gas storage.Method. The article deals with modern methods of mathematical modeling and software when solving problems in a nonlinear formulation. A regulatory analysis of existing methods of LNG transportation has been carried out.Result. Using the mathematical program ANSYS, the rollover process in the liquefied natural gas storage was modeled. In the ANSYS software package, 3d modeling of the process of heat and mass transfer of the stratified liquid in the liquefied natural gas storage was performed. When simulating a rollover phenomenon, the time to its occurrence was 30 minutes, which differs from the experimental value by 1.7%. Based on the results of the calculations, it can be determined that the time to the onset of rollover depends on the concentration of the component layers, on the filling and geometry of the reservoir. These factors lead to an increase in evaporation of liquefied natural gas of 0.04%.Conclusion. The method of numerical experiment allows to determine the distribution of pressure, temperature, density, concentration in the object under study, without resorting to real experiments. The use of the ANSYS software package of computational fluid dynamics in the process of heat and mass transfer of the stratified liquid in the liquefied natural gas storage is necessary when calculating the increased accuracy.