Using ethanol or acetone as the working fluid, visualization of oscillations in steady state was observed visually by high-speed cameras, and temperature oscillating and heat transfer characteristics of closed-loop pl...Using ethanol or acetone as the working fluid, visualization of oscillations in steady state was observed visually by high-speed cameras, and temperature oscillating and heat transfer characteristics of closed-loop plate oscillating heat pipe with parallel channels(POHP-PC) were experimentally investigated by varying liquid filled ratios(50%, 70%, 85%), section scales(1 mm×1 mm and 1 mm×1.5 mm), inclination angles, working fluids and heating inputs. It was found that during operating there was mixed flow consisting of plug flow and annular flow in channels of oscillating heat pipe at steady-state. There was an equilibrium position for working fluid of condenser during oscillating, and periodic oscillations occurred up and down in the vicinity of equilibrium position. With heat input increasing, equilibrium position rose slowly as a result of vapor pressure of evaporation.Evaporation temperature oscillating amplitude possessed a trend of small-large-small and frequency trend was of small-large during steady-state. It may be generally concluded that temperature, whether evaporator or condenser, fluctuated sharply or rose continuously when oscillating heat pipe coming to dry burning state. Simultaneously, it was found that temperature difference of cooling water possibly dropped with heat input rising during dry burning state. Thermal resistance of No. 2 with acetone was lower than that of No. 1 during experiments, but No. 2 achieving heat transfer limit was earlier than No. 1. However, with ethanol, thermal resistance of No. 1 and No. 2 were similar with the heating input less than 110-120 W and filling ratios of 50% and 70%. And with filling ratio of 85%, heating transfer performance of No. 2 was better compared to No. 1 during all the experiments.展开更多
A digital photographic study of pool boiling with binary mixture Rll(CC13)-Rll3(CCl3CF3) was performed on a horizontal transparent heater at pressure of 0.1MPa. A high speed digital camera was applied to record th...A digital photographic study of pool boiling with binary mixture Rll(CC13)-Rll3(CCl3CF3) was performed on a horizontal transparent heater at pressure of 0.1MPa. A high speed digital camera was applied to record the bubble behaviors in boiling process. Strong effects of composition on bubble departure diameter, deparatre time, nucleation density were observed, which was attributed to the nature of the activation of the boiling surface and mass diffusion effects. The bubble departure diameter, departure period and nucleation density as functions of composition for binary mixtures R 11-R 113 were presented respectively. From the video images, it can be concluded that evaporation of microlayer is very important to the growth of bubble. It is also observed that there is not any liquid recruited into the microlayer below the bubble.展开更多
The purpose of this study is to design a tool, adapted to students' individual contexts and to enable students to reflect on their understanding of media characteristics. AHP (analytic hierarchy process) is a struc...The purpose of this study is to design a tool, adapted to students' individual contexts and to enable students to reflect on their understanding of media characteristics. AHP (analytic hierarchy process) is a structured technique for organizing and analyzing complex decisions. Using AHP, students have to define appropriate criteria and priorities for using media. It is expected that students" understanding of the characteristics of different types of media will emerge through reflection. Seventy two university students took part in this research. They were asked to prioritize their ways.of obtaining information about current affairs using sets of media such as TV, books, newspapers and web pages, Twitter and Facebook. AHP enables us to visualize a "real" understanding of media characteristics and students can reflect on that basis. As far as "information sources and media" is concerned, a few students indicated that it was the information source itself that was important rather than the type of media. Our tool fulfils the role of encouraging this type of reflection.展开更多
3D visualization technology is a tool used for displaying, describing, and understanding the characteristics of geologic bodies, and features high efficiency, objective accuracy, visual expression, etc. In this paper,...3D visualization technology is a tool used for displaying, describing, and understanding the characteristics of geologic bodies, and features high efficiency, objective accuracy, visual expression, etc. In this paper, the man-machine interactive interpretation and 3D visualization technology rapidly displaying and analyzing the 3D seismic data of hydrate ore volume is researched and developed using the hybrid rendering technique. Through the integrated interpretation on the 3D space structure, stratum, and seismic attributes, the visualized multi-attribute superimposition analysis is implemented for describing the spatial distribution characteristics of hydrate ore volume and exquisitely describing the subtle geological characteristics of hydrate ore volume. By the hybrid rendering technique, authentication and interpretation are provided for the geological exploration work, so as to greatly enhance the visualization and accuracy of the geological analysis, and also provide a good decision-making foundation for the subsequent development of resources.展开更多
基金Project(51306198)supported by the National Natural Science Foundation of ChinaProject(NR2013K07)supported by Beijing Key Lab of Heating,Gas Supply,Ventilating and Air Conditioning Engineering,China+1 种基金Project(331614013)supported by Beijing University of Civil Engineering and Architecture,ChinaProject(00921915023)supported by Organization Department of Beijing,China
文摘Using ethanol or acetone as the working fluid, visualization of oscillations in steady state was observed visually by high-speed cameras, and temperature oscillating and heat transfer characteristics of closed-loop plate oscillating heat pipe with parallel channels(POHP-PC) were experimentally investigated by varying liquid filled ratios(50%, 70%, 85%), section scales(1 mm×1 mm and 1 mm×1.5 mm), inclination angles, working fluids and heating inputs. It was found that during operating there was mixed flow consisting of plug flow and annular flow in channels of oscillating heat pipe at steady-state. There was an equilibrium position for working fluid of condenser during oscillating, and periodic oscillations occurred up and down in the vicinity of equilibrium position. With heat input increasing, equilibrium position rose slowly as a result of vapor pressure of evaporation.Evaporation temperature oscillating amplitude possessed a trend of small-large-small and frequency trend was of small-large during steady-state. It may be generally concluded that temperature, whether evaporator or condenser, fluctuated sharply or rose continuously when oscillating heat pipe coming to dry burning state. Simultaneously, it was found that temperature difference of cooling water possibly dropped with heat input rising during dry burning state. Thermal resistance of No. 2 with acetone was lower than that of No. 1 during experiments, but No. 2 achieving heat transfer limit was earlier than No. 1. However, with ethanol, thermal resistance of No. 1 and No. 2 were similar with the heating input less than 110-120 W and filling ratios of 50% and 70%. And with filling ratio of 85%, heating transfer performance of No. 2 was better compared to No. 1 during all the experiments.
基金Supported by the National Natural Science Foundation of China (No.10355001) and the Century Programme of ChineseAcademy of Sciences.
文摘A digital photographic study of pool boiling with binary mixture Rll(CC13)-Rll3(CCl3CF3) was performed on a horizontal transparent heater at pressure of 0.1MPa. A high speed digital camera was applied to record the bubble behaviors in boiling process. Strong effects of composition on bubble departure diameter, deparatre time, nucleation density were observed, which was attributed to the nature of the activation of the boiling surface and mass diffusion effects. The bubble departure diameter, departure period and nucleation density as functions of composition for binary mixtures R 11-R 113 were presented respectively. From the video images, it can be concluded that evaporation of microlayer is very important to the growth of bubble. It is also observed that there is not any liquid recruited into the microlayer below the bubble.
文摘The purpose of this study is to design a tool, adapted to students' individual contexts and to enable students to reflect on their understanding of media characteristics. AHP (analytic hierarchy process) is a structured technique for organizing and analyzing complex decisions. Using AHP, students have to define appropriate criteria and priorities for using media. It is expected that students" understanding of the characteristics of different types of media will emerge through reflection. Seventy two university students took part in this research. They were asked to prioritize their ways.of obtaining information about current affairs using sets of media such as TV, books, newspapers and web pages, Twitter and Facebook. AHP enables us to visualize a "real" understanding of media characteristics and students can reflect on that basis. As far as "information sources and media" is concerned, a few students indicated that it was the information source itself that was important rather than the type of media. Our tool fulfils the role of encouraging this type of reflection.
文摘3D visualization technology is a tool used for displaying, describing, and understanding the characteristics of geologic bodies, and features high efficiency, objective accuracy, visual expression, etc. In this paper, the man-machine interactive interpretation and 3D visualization technology rapidly displaying and analyzing the 3D seismic data of hydrate ore volume is researched and developed using the hybrid rendering technique. Through the integrated interpretation on the 3D space structure, stratum, and seismic attributes, the visualized multi-attribute superimposition analysis is implemented for describing the spatial distribution characteristics of hydrate ore volume and exquisitely describing the subtle geological characteristics of hydrate ore volume. By the hybrid rendering technique, authentication and interpretation are provided for the geological exploration work, so as to greatly enhance the visualization and accuracy of the geological analysis, and also provide a good decision-making foundation for the subsequent development of resources.