Measuring the VOLUME of a BUBBLE, especially at its detachment, is a basic subject in gas-liquid two-phase flow research. A new indirect method for this measurement under constant flow conditions is presented. An electronic device is designed and constructed based on laser beam intensity. This device calculates the frequency of the BUBBLE formation by measuring the total time of the formation process and counting the number of BUBBLEs crossing the laser beam. The BUBBLE VOLUME at detachment can be calculated by dividing the VOLUMEtric flow rate of air by the frequency of BUBBLE formation. The latter and the BUBBLE VOLUME at detachment are measured for three different heights of water above the tip of the orifice (50, 100, and 150 mm), three orifice diameters (1, 2, and 3 mm), and different gas flow rates between 2000 and 10000 ml/hr. Comparing and validating the results with the results of the image processing (IP) method and the correlations presented by other studies shows the strong accuracy of the present method.

The gas-liquid two-phase flow with interfacial behaviors and BUBBLE-liquid interactions is widely encountered in industrial processes such as that in gas-liquid reactors. The complicated phase structure makes it difficult to be modeled. The present work proposes a multi-scale mathematical model to simulate the bubbly flow in a square column. The VOLUME of fluid (VOF) method is applied to treat the separated interface, and the discrete BUBBLE model (DBM) is incorporated to handle the dynamics of dispersed BUBBLEs. The hybrid model is validated against the benchmark experimental data to study the accuracy and suitability of the modeling framework for bubbly flows. And the influence of interphase forces on bubbly flow patterns and velocity profiles is investigated. It is found that the employment of both pressure gradient force and Ishii-Zuber drag model provides fairly good agreements with experimental data for velocity profiles.

The phenomenon of nuclear boiling has always been recognized suitable for heat transfer between different boiling regimes. Study on boiling is considered as a new field which meets different research and industrial needs such as heat transfer in nuclear reactors, cooling units, rocket motors, electronic equipment cooling, batteries, etc. In this study, a chamber with immiscible fluid, water, steam, and air, having a side wall with uniform heat flux has been studied in 3D. To do so, we first considered the prediction of the heat flux interval for which the boiling occurs in the form of nuclear boiling. In this study, two-phase fluid VOLUME (VOF) approach was used for modelling boiling on the vertical wall and two-phase flow. In this research, Ansys software package was used for numerical modelling and numerical simulation. Distribution of the velocity field follows more uniform pattern in dimensionless heights less than 0.9. In this study, BUBBLEs are only present near a wall with heat flux that has a lower Rayleigh number. Also, existence of these BUBBLEs on the wall, which prevents fluid infiltration, affects vortices caused by natural convection. However, the general and uniform patterns of vortices remain unchanged in most part of the fluid, which is because of the limited amount of BUBBLEs near the wall with heat flux. Natural convection increases the height of fluid inside the chamber, which leads to the formation of stronger vortices at a dimensionless height of 0.9 that has a high Raleigh number due to high heat flux. In this case, the continuous use of heat flux gives rise to the production of BUBBLEs over time.

Local velocities and aspect ratios of rising BUBBLEs were measured to investigate the effects of BUBBLE detachment shape on rising BUBBLE hydrodynamics. Two types of capillary were employed to generate BUBBLEs of identical VOLUME: one glassy nozzle aligned vertically and the other stainless steel needle aligned horizontally. Horizontally injected BUBBLEs had spherical initial shape and their values of aspect ratio slightly fluctuated around unity. However, vertically injected BUBBLEs had surface-stretched initial shape and their values of aspect ratios decreased sharply from 1. 1 to 0. 65. There is a notable correspondence between the variation of local velocities and aspect ratios which reflects the relevance of the detachment shape of the BUBBLEs to their surface energy. Correlations of Taylor & Acrivos and Vakhrushev & Efremov for aspect ratio were examined by experimental data.

Given the importance of the securities market in each country's economy and the adverse effects of the price BUBBLE on the irrational fluctuations of the stock market, it is clear that it must be prevented,therefore, with reference to the ambiguity of the factors causing the price BUBBLE, research is underway. Investigating the relationship between the VOLUME of transactions and the value of transactions with the price BUBBLE in different industries of the Stock Exchange during the years 2006 to 2016 is a step towards recognizing this phenomenon. To investigate these communications, we used DCC-GJR-GARCH, diagonal BEKK and COPULA models. The results of the study of the relationship between the VOLUME of exchanges and the value of exchanges with price BUBBLEs suggest that there is a negative and complete correlation between them. In relation to the study of the relationship between price BUBBLEs and research variables, we found that oil prices have a reverse and significant relationship with BUBBLE prices. Other variables are not meaningful relationships with price BUBBLEs. Also, in the study between variables of research with VOLUME of transactions, it was determined that changes in tax VOLUME and oil price variables have a reverse and significant relationship with the VOLUME of transactions and the value of transactions with the VOLUME of transactions has a direct and significant relationship.