Flow pattern or velocity distribution on a distillation tray is of great importance in determining tray efficiency. And design of distillation process is mainly rely on experimental data which also can be used in veri...Flow pattern or velocity distribution on a distillation tray is of great importance in determining tray efficiency. And design of distillation process is mainly rely on experimental data which also can be used in verification of mathematical model for describing the flow pattern on a tray.In this paper,hot-film anemometer with X-type probe is applied to the measurement of gas-liquid two-phase flow on a sieve tray.First,a calibration method that used in this paper is proposed and a computational model for data processing is presented.Then the threshold method used to separate vapor signals from those of the liquid is described.Finally,typical measuring results,which include the magnitude and direction of local velocity,and the distribution of turbulent kinetic energy,are presented.展开更多
The present study concerns the measurement of the convective heat transfer coefficient on the solid-fluid interface by the pulsed photothermal method.This non-intrusive technique is apphed for the measurement of the l...The present study concerns the measurement of the convective heat transfer coefficient on the solid-fluid interface by the pulsed photothermal method.This non-intrusive technique is apphed for the measurement of the local heat transfer coefficients in cooling of a rectangular slab that simulates an electronic component.The heat transfer coefficient is deduced from the evolution of the transient temperature induced by a sudden deposit of a luminous energy on the front face of the slab.In order to draw up the heat transfer cartography by a non-destructive tool, the infrared thermography has been used.Two inverse techniques for the identification of the heat transfer coefficient are presented here.The first one is based on the assumption that heat transfer coefficient remains constant during the pulsed experiment,and the second one considered it variable in space and time.The temporal and spatial evolutions are expressed as a constant heat transfer coefficient(h_0)multiplied by a function of time and space f(x,t).The function f is deduced from the resolution of the conjugated convection-conduction problem,by a control volume technique for the case of thermally thick sample.The results are given for different air velocities and deflection angles of the flow.展开更多
文摘Flow pattern or velocity distribution on a distillation tray is of great importance in determining tray efficiency. And design of distillation process is mainly rely on experimental data which also can be used in verification of mathematical model for describing the flow pattern on a tray.In this paper,hot-film anemometer with X-type probe is applied to the measurement of gas-liquid two-phase flow on a sieve tray.First,a calibration method that used in this paper is proposed and a computational model for data processing is presented.Then the threshold method used to separate vapor signals from those of the liquid is described.Finally,typical measuring results,which include the magnitude and direction of local velocity,and the distribution of turbulent kinetic energy,are presented.
基金support of the Comite Mixte Franco-Tunisien pour la Cooperation Universitaire(Project CMCU N°08G1131)
文摘The present study concerns the measurement of the convective heat transfer coefficient on the solid-fluid interface by the pulsed photothermal method.This non-intrusive technique is apphed for the measurement of the local heat transfer coefficients in cooling of a rectangular slab that simulates an electronic component.The heat transfer coefficient is deduced from the evolution of the transient temperature induced by a sudden deposit of a luminous energy on the front face of the slab.In order to draw up the heat transfer cartography by a non-destructive tool, the infrared thermography has been used.Two inverse techniques for the identification of the heat transfer coefficient are presented here.The first one is based on the assumption that heat transfer coefficient remains constant during the pulsed experiment,and the second one considered it variable in space and time.The temporal and spatial evolutions are expressed as a constant heat transfer coefficient(h_0)multiplied by a function of time and space f(x,t).The function f is deduced from the resolution of the conjugated convection-conduction problem,by a control volume technique for the case of thermally thick sample.The results are given for different air velocities and deflection angles of the flow.
