Abstract

In recent years efforts have been realised to increase the compression of the phenomena associated to the liquid - gas two-phase flow, for which mathematical models have settled down that try to reflect the comportment of the flow as it is the case of the model of both Fluid. A cause of the complexity that represents the modelled one is the mass transfer, moment and energy between phases due to the interaction between phases. At the moment the used models of calculation in CFD and thermal hydraulics codes trust experimental correlations highly employees of the flow regime to determine the interface area, nevertheless this procedure does not reflect the physical nature and they become appear irregularities in the zone of interphase due to phenomena of transport not described by these models. In this one sense a theory of transport of interface area has been recently propose that seems to be a viable solution to the problem of the obtaining of constituent equations of the interface area and with her, the closing of the model. This equation consists of convective terms and temporary that can be solved mathematically or analytically, on the other hand it contains terms source and drain that represent the creation and destruction of bubbles that not yet completely have been modelled; for the understanding of these terms it is required experimental information and this one deficiency the one that tries to palliate this one work by means of the obtaining of an experimental data base that contributes useful information for the modeleld two-phase systems. 
For the obtaining of the data base it was necessary to design, to construct and to orchestrate an experimental installation that allowed to the formation of two-phase flows underwater-to-air with superficial velocities of liquid phase and gas similar to the existing ones in the present nuclear reactors. The system of formation of two-phase mixture that was designed and constructed allows the obtaining of several regimes of flow, in its operation it uses porous means frequently employees by other similar groups of investigation in applications and configurations. 
Between the used techniques of measurement is a complete system of acquisition of image of high speed of capture, laser anemometry that required of the development of a specific methodology in the signal processing, and sensors of conductivity of four ends that were developed explicitly for this one work of investigation. 


In the obtaining of a useful prototype of a conductivity sensor the development of a scheme of processing of signal that allowed to extract of the electrical signals useful information and at the same time to discriminate the contracted electrical noise in the signal, in addition given its high specialization was necessary, this sensor was to be construed of way manual, too was developed a manufacture methodology that considerably reduced to the cost and time of construction, increasing at the same time the quality and reliability of this instrument as well as the one of its results. The experiments developed in this investigation imply local measures of principals parameters of two-phase flow as they are the concentration of interface area, fraction of hollows, interface speed, distribution of I number of bubbles, size of bubble and superficial speed of the liquid phase. The realised measurements allow to know the evolution the flow structures in regimes bubbly and in transition bubbly to slug, for it the local techniques of measurement were used before described. Like part of the validation of the techniques and used processes of measurement, some results were compared with the obtained ones by another group of investigation with an ample trajectory in this one field. 
The obtained results allow to know temporary values average the parameters of flow before mentioned and have been compared with the obtained ones by other authors. The used instrumentation is able to offer to useful information about the evolution these parameters with respect to the variation of the initial conditions of flow. Some processes of interaction between bubbles with base to developments realised by other authors like part of the validation of the obtained data were evaluated. One hopes that the obtained data allows the development of the constituent relations like is it the equation of transport of interface area that reflected the true influence of the interface area on comportment global of the two-phase flow.