It is well know that pure substances (or almost pure) can be maintained in the liquid phase for t... more It is well know that pure substances (or almost pure) can be maintained in the liquid phase for temperatures much higher than those of the liquid-vapor phase change. In these superheated cases, it is necessary to startup the phase change through some adequate nucleation mechanism, generating a very fast sequence of phenomena. In the present study, a confined liquid (distillated water) was subjected to an adequate situation of pressure and temperature that allowed forming macro cavities, and because of the sudden expansion, generated a piston-like movement for the liquid dislocating. First tests were performed, in which the generation and collapse of cavities with lengths of about 25 cm were observed. The experimental system allows a good approximation to a one-dimensional movement of the volume of water, but also allows to observe intriguing geometrical patterns forming at the upper surface of this volume. The results show that the sudden expansions, with high accelerations and dece...
WIT Transactions on Engineering SciencesComputational Methods in Multiphase Flow VII, 2013
Considering liquid phases, it is well know that pure substances (or almost pure) can be maintaine... more Considering liquid phases, it is well know that pure substances (or almost pure) can be maintained in the liquid phase for temperatures much higher than those of the liquid-vapor phase change. In these superheated cases, it is necessary to startup the phase change through some adequate mechanism, generating a very fast sequence of phenomena. In the present study, a confined liquid (water) was subjected to an adequate situation of pressure and temperature that allowed forming macro cavities, which sudden expansion generated a piston-like movement while the liquid dislocated. The geometrical arrangements of the equipment allow the “use” of the reaction force, by stretching a spring. The aim of this study was to analyse the evolution of macro cavities generated by heating water under low pressure, describing the details of their dynamics and work production. First tests were performed using distilled water and a glass container (an adequately prepared mercury lamp) in which the generation and collapse of cavities with diameter of about 10-1m were observed, and peak forces of 400 to 500N were measured. A one-dimensional governing equation was obtained from the usual conservation equations, and the results show that it considers the relevant aspects for the quantification of the observed movements. A second experimental system, that allows a better approximation to the one-dimension movement, is also presented. The results show that the sudden expansions can be used to generate work (although a small quantity), which may be of interest in situations where energy can be freely obtained from the environment, like the solar energy.
It is well know that pure substances (or almost pure) can be maintained in the liquid phase for t... more It is well know that pure substances (or almost pure) can be maintained in the liquid phase for temperatures much higher than those of the liquid-vapor phase change. In these superheated cases, it is necessary to startup the phase change through some adequate nucleation mechanism, generating a very fast sequence of phenomena. In the present study, a confined liquid (distillated water) was subjected to an adequate situation of pressure and temperature that allowed forming macro cavities, and because of the sudden expansion, generated a piston-like movement for the liquid dislocating. First tests were performed, in which the generation and collapse of cavities with lengths of about 25 cm were observed. The experimental system allows a good approximation to a one-dimensional movement of the volume of water, but also allows to observe intriguing geometrical patterns forming at the upper surface of this volume. The results show that the sudden expansions, with high accelerations and dece...
WIT Transactions on Engineering SciencesComputational Methods in Multiphase Flow VII, 2013
Considering liquid phases, it is well know that pure substances (or almost pure) can be maintaine... more Considering liquid phases, it is well know that pure substances (or almost pure) can be maintained in the liquid phase for temperatures much higher than those of the liquid-vapor phase change. In these superheated cases, it is necessary to startup the phase change through some adequate mechanism, generating a very fast sequence of phenomena. In the present study, a confined liquid (water) was subjected to an adequate situation of pressure and temperature that allowed forming macro cavities, which sudden expansion generated a piston-like movement while the liquid dislocated. The geometrical arrangements of the equipment allow the “use” of the reaction force, by stretching a spring. The aim of this study was to analyse the evolution of macro cavities generated by heating water under low pressure, describing the details of their dynamics and work production. First tests were performed using distilled water and a glass container (an adequately prepared mercury lamp) in which the generation and collapse of cavities with diameter of about 10-1m were observed, and peak forces of 400 to 500N were measured. A one-dimensional governing equation was obtained from the usual conservation equations, and the results show that it considers the relevant aspects for the quantification of the observed movements. A second experimental system, that allows a better approximation to the one-dimension movement, is also presented. The results show that the sudden expansions can be used to generate work (although a small quantity), which may be of interest in situations where energy can be freely obtained from the environment, like the solar energy.
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