THERMAL EFFECT ON BUBBLE RISE – AN EXPERIMENTAL STUDY

Abstract

This paper presents the findings of an experimental study on the effect of temperature gradient on bubble rise velocity in water. At the bottom of the chamber holding water, a bubble (equivalent diameter, req 1 mm) is created and rises through it. At a height of 60 cm from the chamber’s bottom, a high-speed camera (1000 fps, Kodak, Model 1000 HRC) is mounted with a 90 mm Macro lens. It is connected to a computer. For image capture and processing, the commercial tools Sigma Scan Pro 5.0 and Adobe Photoshop are used. The chamber can be heated with infrared light, resulting in a constant temperature gradient of 1.10C/cm between 30 and 40 cm above the needle in the water. Bubble rise characteristics, such as bubble size and rise velocity, are determined both in the presence and absence of a temperature gradient. The current study clearly demonstrates that this gradient causes an additional increase in terminal rise velocity.