A T-junction is a fundamental fluid element prevalent in pipe networks of water supplies and power plants. In the present study, a double T-junction was investigated for flow instability and fluid vibration. Both axi-...A T-junction is a fundamental fluid element prevalent in pipe networks of water supplies and power plants. In the present study, a double T-junction was investigated for flow instability and fluid vibration. Both axi-aligned and skewed double T-junctions are examined from viewpoint of flow instability. With single-phase flow in an open-ended double T-junction, fluid vibration is induced in both side branches because of a high shear rate with a point of inflection. The frequency of vibration in the downstream branch is higher than that in the upstream branch. Except for the upstream branch in the skewed double T-junction, the frequency is higher than that in a single T-junction. The fluid vibrations are closely associated with the fluid interference created by the presence of the two side branches.展开更多
Sedimentary processes have direct effects on the geometry, distribution, and geophysical and geochemical properties of sedimentary rocks. Being able to qualitatively and quantitatively visualize the movement vector of...Sedimentary processes have direct effects on the geometry, distribution, and geophysical and geochemical properties of sedimentary rocks. Being able to qualitatively and quantitatively visualize the movement vector of sediments in fluid media is essential for understanding the complicated earth surface processes. Nonintrusive measuring and observing the interaction between the movement of fluid media and particles by a laser sheet flow visualization technique requires a light source that is thin and monochromatic. Yet, an ideal laser sheet generator is rather expensive and inaccessible, especially for schools and universities residing in low-income countries. This project is proposing a less-expensive option for a laser sheet source for nonintrusive flow visualization and modeling. Here, cylindrical lens is used to convert from point laser into sheet laser. Multiple combinations of laser diodes of various wavelength (nanometer) and power (milliwatt) and cylindrical lenses of various dimensions are analyzed. The pair that is able to produce the thinnest and brightest light sheet is not only effective but also affordable. The combination of manufactured laser module of 532 nm 50 mW and a single rod lens is able to generate a light sheet that is less than 4 mm thick. When choosing a laser module, this research recommends one at a wavelength of 532 nm with any electric power (high wattage results in high lumens).展开更多
A three - dimenslonal finite element model is developed to deal with the polymeric liquid flow in coat - hanger die. This model is used to predict the flow behavior of the 2％ CMC/watsr solution in the coat - hanger d...A three - dimenslonal finite element model is developed to deal with the polymeric liquid flow in coat - hanger die. This model is used to predict the flow behavior of the 2％ CMC/watsr solution in the coat - hanger die with linearly taper manifolds and its validity is experimentally verified quantitatively and qualitatively by using Laser Doppler Velocimetry and Particle Image Velocimetry respectively.展开更多
文摘A T-junction is a fundamental fluid element prevalent in pipe networks of water supplies and power plants. In the present study, a double T-junction was investigated for flow instability and fluid vibration. Both axi-aligned and skewed double T-junctions are examined from viewpoint of flow instability. With single-phase flow in an open-ended double T-junction, fluid vibration is induced in both side branches because of a high shear rate with a point of inflection. The frequency of vibration in the downstream branch is higher than that in the upstream branch. Except for the upstream branch in the skewed double T-junction, the frequency is higher than that in a single T-junction. The fluid vibrations are closely associated with the fluid interference created by the presence of the two side branches.
文摘Sedimentary processes have direct effects on the geometry, distribution, and geophysical and geochemical properties of sedimentary rocks. Being able to qualitatively and quantitatively visualize the movement vector of sediments in fluid media is essential for understanding the complicated earth surface processes. Nonintrusive measuring and observing the interaction between the movement of fluid media and particles by a laser sheet flow visualization technique requires a light source that is thin and monochromatic. Yet, an ideal laser sheet generator is rather expensive and inaccessible, especially for schools and universities residing in low-income countries. This project is proposing a less-expensive option for a laser sheet source for nonintrusive flow visualization and modeling. Here, cylindrical lens is used to convert from point laser into sheet laser. Multiple combinations of laser diodes of various wavelength (nanometer) and power (milliwatt) and cylindrical lenses of various dimensions are analyzed. The pair that is able to produce the thinnest and brightest light sheet is not only effective but also affordable. The combination of manufactured laser module of 532 nm 50 mW and a single rod lens is able to generate a light sheet that is less than 4 mm thick. When choosing a laser module, this research recommends one at a wavelength of 532 nm with any electric power (high wattage results in high lumens).
文摘A three - dimenslonal finite element model is developed to deal with the polymeric liquid flow in coat - hanger die. This model is used to predict the flow behavior of the 2％ CMC/watsr solution in the coat - hanger die with linearly taper manifolds and its validity is experimentally verified quantitatively and qualitatively by using Laser Doppler Velocimetry and Particle Image Velocimetry respectively.
