Visualization Techniques of Closed Conduit Flows by Hydrogen Bubble Methods

抄録

Many techniques have been developed for the visualization of fluid flows. Dye, smoke, A1 powder and tuft have been often used to visualize flow patter. But, each technique is intended for its qualitative use and not supposed to yield quantitative information. Especially, in case of high speed, transient and separated flows, they can provide no information. A new technique called "Hydrogen bubble method" provides very fine bubbles in the water flow as a tracer. These bubbles can thus illustrate the pattern of the water flows in considerable detail. In this paper, the uncertainty of the hydrogen bubble method by buoyancy, wakes and absorption is examined. This method can be used successfully to give a flow profile for the range up to the velocity 6m/sec. Finally, flow profiles for a transverse plate fin are presented as an illustration.