In order to understand the internal flow pattern of a heat exchanger, new method flow visualization is developed using water paint instead of the aluminum powder or saw dust in conventional way. A mixture of water and white water paint adding a little amount of surface active agent is adopted to obtain the internal flow pattern of heat exchanger without sticking of tracer to the model surface. The mixture liquid having weight ratio of water, white water paint and surface active agent 4:1:1/2000 shows the best condition for visualization. Using this tracer, it is possible to trace the time-line and the streak-line around the model clearly. Various kinds of fin arrangement of the exchanger are tested.
The purpose of this study is to investigate how the flow patterns of jet-wedge system change by setting a pair of plates at right angles to the jet axis. The flow is visualized by the color tracer injection method. When the distance between the jet axis and the tips of a pair of plates which is set downstream the nozzle exit is made small, the displacement width of the jet oscillation becomes small. On the orther hand, though the distance is changed, the Strouhal number of the jet oscillation remains nearly constant. Further decrease of the distance calms the jet oscillation.
The flow in the intersecting region of two streams inside an X-shaped flow network is complex due to combined consequence of the ramming phenomena and the centri fugal force induced by the flow passage geometry. The flow visualization study was conducted using a recirculating flow loop with an intersecting duct installed between two head tanks of different heads. In this study, both the symmetric and asymmetric flows are investigated by the string method to visualize flow oscillations of the shear layer in the intersecting region. The difference in flow branching from the intersecting region due to a change in the intersecting angle is disclosed. The variation of oscillation amplitudes is found to be small in 60°and 90°intersecting ducts. It is also found that the center position of oscillation amplitudes is at one side and the dispersion of flow oscillation is small in case of the asymmetric level at upper tanks.
Recently electrical measurement technique for geophysical survey has become to contribute to the problems in groundwater delineation, evaluation and protection, landfills, earth and water contamination, chemical waste disposal, nuclear waste disposal, earthquake risk evaluation, radon emanations, landslides, land subsidence, crop-land salinization, and general geoengineering problems. In this paper, a fundamental problem on electric field measurement for high accuracy resistivity interpretation has been investigated by the three-dimensional resistance network algorithm. Usually, the conventional direct current resistivity methods include mainly two kinds of electrode array moving systems, i. e., so-called the first potential and the second potential methods. Also the potential methods can be conducted by not only the potential apparent resistivity measurement, but also the electric field measurement by which the response due to target inhomogeneity may be enhanced effectively including its visualization for resistivity high-resolution prospecting.