Effect of Temperature on Cavitating Jet

Oike and Kobayashi* presented an experiment study on the effect of water temperature on cavitating jets. Here are the highlights of their article.

First of all, theirexperiments confirmed a known effect of stand-off distance on erosion (as shownto the right). There are two peak erosion points that occurred when the ratiosof stand-off distance to nozzle diameter (s/d) are 15X and 55X. The first peakis associated with the erosion pit at the center of impact while the secondpeak is associated with the outer ring (as shown in the photo).

To study the effect oftemperature on erosion, they used 4 sets of injection/surrounding watertemperatures, (20ºC, 20ºC), (20ºC, 50ºC), (50ºC, 20ºC), (50ºC, 50ºC), in theirexperiments. When s/d=15, the higher injection water temperature increased themass loss by about 3X, regardless surrounding water temperature. When s/d=55,the higher temperatures in both injection and surrounding water increased themass loss by about 4X. The authors believed that the higher injection watertemperature promotes the occurrence of cavitation bubbles in the jet and thusthe erosion power. They also believed that increasing both the injection andsurrounding temperatures promotes the occurrence of bubbles in the cavitationcloud surrounding the jet.

* Oike, M. and Kobayashi, R. (2006) Influence of water temperatures on cavitating jet, Proceedings of the 8^th Pacific Rim International Conference on Water Jet Technology, Oct. 10-12, Qingdao, China, Paper 7.