[PDF] Standard Method Of Vibratory Cavitation Erosion Test Modificed eBook

Author : Y. Meged
Publisher :
Page : 30 pages
File Size : 36,60 MB
Release : 2014
Category : Cavitation erosion
ISBN :

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In the framework of the International Cavitation Erosion Test (ICET), 119 vibratory cavitation erosion tests were performed. Seventy of these tests were with vibrating specimens (VRV), and forty-nine with stationary specimens (VRS). From these tests, twenty tests of each type were chosen for this study. VRV tests are covered by ASTM G32-10, whereas for VRS, no standard has yet been published. This anomaly stems from the difficulties encountered in both testing and evaluating of VRS tests. All forty cavitation erosion-time curves were analyzed by the Transient Response for Erosion (TRE) method. For each curve, all three parameters were determined, namely: time lag (TL), time constant (?), and the asymptotic value of the mean depth of erosion, mean depth of erosion (MDE) MDEMAX. These parameters were further applied to calculate the scatter of test results as obtained from various specimens tested under identical conditions. This method enables the determination of the absolute and relative scatter values at any time value along the test. Finally, several guidelines are specified for preparation of a future VRS standard.

Author : Y. Meged
Publisher :
Page : 10 pages
File Size : 39,78 MB
Release : 2003
Category : Modeling
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The rate of mass loss in vibratory cavitation erosion tests varies with time. As a consequence, this process is treated empirically. It is suggested by the author that the cumulative mass loss-time curve test results can be represented accurately by the Weibull cumulative distribution function. This model was verified for 26 tests of nine metals. Among these metals is Ni 200, which is a standard reference material for erosion tests. This model allows treating the results of vibratory cavitation erosion tests analytically, thereby obtaining invaluable information from the test data.

Author : Georges L. Chahine
Publisher :
Page : 35 pages
File Size : 45,30 MB
Release : 2018
Category : Cavitation erosion
ISBN :

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Predicting cavitation erosion under full-scale operating conditions is difficult and relies on laboratory testing using accelerated methods such as ASTM G32-09, Standard Test Method for Cavitation Erosion Using Vibratory Apparatus, and ASTM G134-95, Standard Test Method for Erosion of Solid Materials by a Cavitating Liquid Jet. The main difficulty is that full-scale cavitation intensity is often unknown, and correlating cavitation field characteristics of the accelerated method and the full scale is not obvious. The problem is more acute for compliant polymeric coatings, used for protection or repair of parts subject to cavitation. Extensive testing of such materials shows that, unlike metallic surfaces, they are highly resistant to low-intensity cavitation but fail catastrophically when the intensity exceeds a certain threshold. Such behavior creates the risk of accepting a candidate coating for its resistance to cavitation if the coating was tested at a low cavitation intensity not representative of the application field conditions. This highlights the need to conduct tests with a range of cavitation intensities rather than a single intensity. This article uses results from extensive tests under various forms of cavitation to propose a generalized definition of cavitation intensity. It then presents data on the response of both metals and polymeric coatings to various levels of accelerated cavitation. A new method to test the coatings at varying cavitation intensities is then presented. Such tests provide maps of material resistance to different levels of cavitation and are helpful to make an informed decision. The tests also show that during cavitation exposure, the coatings are subjected not only to mechanical stress but also to significant heating, which dynamically modifies their properties during the exposure. Temperature rise in the coating when exposed to cavitation is directly connected to the cavitation intensity to which it is exposed, and this interaction needs to be considered.

Author : Y. Meged
Publisher :
Page : 10 pages
File Size : 50,49 MB
Release : 2005
Category : Affected material zone
ISBN :

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The resistance of materials to liquid impingement erosion and to cavitation erosion are considered related properties. Hence, test methods dealing with these erosion mechanisms that are covered by ASTM standards are considered as alternative tests for some applications.These methods consist of vibratory cavitation erosion, cavitating liquid jet erosion, and liquid impingement erosion.