| Due to internal attractive forces of a liquid, air bubbles within the liquids are compressed. The resulting pressure (bubble pressure) rises at a decreasing bubble radius. The bubble pressure method makes use of this bubble pressure which is higher than in the surrounding environment (water). A gas stream is pumped into a capillary that is immersed in a fluid. The resulting bubble at the end of the capillary tip continually becomes bigger in surface; thereby, the bubble radius is decreasing. |
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| The pressure rises to a maximum level. At this point the bubble has achieved its smallest radius (the capillaryradius) and begins to form a hemisphere. Beyond this point the bubble quickly increases in size and soon bursts, tearing away from the capillary, thereby allowing a new bubble to develop at the capillary tip. It is during this process that a characteristic pressure pattern develops (see picture), which is evaluated for determining the surface tension. |
Bubble pressure method for measuring the dynamic surface tension
| Because of its many potential applications, surface tension has become an important process parameter; it is therefore necessary to measure surface tension simply and efficiently. Characterized by dynamic measurements and continuous method of operation the bubble pressure method accomplishes this goal, as it determines the dynamic surface tension of liquids quickly and easily. |
