Laser-induced fluorescence for high-pressure flow visualization

A pressure-exchange ejector transferring energy by compression and expansion waves has the potential for higher efficiency. The width and position of each port are essential in pressure-exchange ejector design. A dimensionless time τ expressing both port widths and the positions of port ends was introduced. A prototype was designed and the experimental system was set up. Many sets of experiment with different geometrical arrangements were conducted. The results suggest that the efficiency greatly changes with the geometrical arrangements. The efficiency is about 60% at proper port widths and positions, while at improper geometrical arrangements, the efficiency is much lower and the maximum deviation may reach about 20%. The proper dimensionless port widths and positions at different operating conditions are obtained. For a fixed overall pressure ratio, the widths of the high pressure flow inlet and middle pressure flow outlet increase as the outlet pressure increases and the low pressure flow inlet width is reduced with a larger outlet pressure. The middle pressure flow outlet (MO) opening end remains constant at different outlet pressures. The positions of the high pressure flow inlet (HI) closed end and the low pressure flow inlet (LI) open end increase with the elevation of outlet pressure, however, the distance between the HI closing end and the LI opening end is constant. The port widths and positions have a significant influence on the performance of the pressure-exchange ejector. The dimensionless data obtained are very valuable for pressure-exchange ejector design and performance optimization.

Download Full-text

Acetone planar laser-induced fluorescence for supersonic flow visualization in air and nitrogen jet

International Journal of Mechanical and Materials Engineering ◽

10.1186/s40712-014-0028-1 ◽

2014 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Vikas M Shelar ◽

Shrisha Rao MV ◽

GM Hegde ◽

G Umesh ◽

G Jagadeesh ◽

...

Keyword(s):

Supersonic Flow ◽

Flow Visualization ◽

Laser Induced Fluorescence ◽

Planar Laser Induced Fluorescence ◽

Planar Laser ◽

Supersonic Flow Visualization

Download Full-text

Microfluidic Control Board for High-Pressure Flow, Composition, and Relative Permittivity

Analytical Chemistry ◽

10.1021/acs.analchem.8b02758 ◽

2018 ◽

Vol 90 (21) ◽

pp. 12601-12608 ◽

Cited By ~ 5

Author(s):

Martin Andersson ◽

Karolina Svensson ◽

Lena Klintberg ◽

Klas Hjort

Keyword(s):

High Pressure ◽

Relative Permittivity ◽

Control Board ◽

Pressure Flow

Download Full-text

Direct Observation of Filling Process and Porosity Prediction in High Pressure Die Casting

Materials ◽

10.3390/ma12071099 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1099 ◽

Cited By ~ 3

Author(s):

Hanxue Cao ◽

Chao Shen ◽

Chengcheng Wang ◽

Hui Xu ◽

Juanjuan Zhu

Keyword(s):

Numerical Simulation ◽

High Pressure ◽

Flow Visualization ◽

Flow Pattern ◽

Experimental Verification ◽

Die Casting ◽

Filling Process ◽

High Pressure Die Casting ◽

Visualization Experiment ◽

Pressure Die Casting

Although numerical simulation accuracy makes progress rapidly, it is in an insufficient phase because of complicated phenomena of the filling process and difficulty of experimental verification in high pressure die casting (HPDC), especially in thin-wall complex die-castings. Therefore, in this paper, a flow visualization experiment is conducted, and the porosity at different locations is predicted under three different fast shot velocities. The differences in flow pattern between the actual filling process and the numerical simulation are compared. It shows that the flow visualization experiment can directly observe the actual and real-time filling process and could be an effective experimental verification method for the accuracy of the flow simulation model in HPDC. Moreover, significant differences start to appear in the flow pattern between the actual experiment and the Anycasting solution after the fragment or atomization formation. Finally, the fast shot velocity would determine the position at which the back flow meets the incoming flow. The junction of two streams of fluid would create more porosity than the other location. There is a transition in flow patterns due to drag crisis under high fast shot velocity around two staggered cylinders, which resulted in the porosity relationship also changing from R1 < R3 < R2 (0.88 m/s) to R1 < R2 < R3 (1.59 and 2.34 m/s).

Download Full-text