Thin Layer Activation is a nuclear technique that has key advantages over other wear measuring techniques for mechanical systems,especially for in site experiments on equipment important to safety in nuclear plants.St...Thin Layer Activation is a nuclear technique that has key advantages over other wear measuring techniques for mechanical systems,especially for in site experiments on equipment important to safety in nuclear plants.Still,it incurs radioactive dose and,thus,must be proved radiologically safe before use,otherwise,the utilization of this technique may be hindered inviable.Proving said technique is safe previous to any operational/monetary cost is key,providing a methodology for this early assertion is the main contribution of this work—here,only non-occupationally exposed individuals are considered.This work offers a methodology,through a case study,to ascertain the Thin Layer Activation parameters to obtain safe levels of radioactive dose while maintaining statistically reliable results.This methodology consists of using simulations,through the Monte Carlo Method,to obtain the floors and ceilings for the previously mentioned activation parameters based on operation and work conditions on site.展开更多
Abradable seal rubber has been widely used in aero-engine fans to improve their efficiency by reducing the clearance between rotating and stationary components. To investigate the high-speed scraping behavior between ...Abradable seal rubber has been widely used in aero-engine fans to improve their efficiency by reducing the clearance between rotating and stationary components. To investigate the high-speed scraping behavior between a vulcanized silicone rubber and a Ti-6Al-4V fan blade and evaluate the abradable performance of seal rubber, abrasion tests were conducted at a blade tip velocity of 50–300 m/s with an incursion rate of 100 lm/s. The influences of the blade tip velocity on the wear mechanism and interaction forces were specially analyzed. It is shown that abrasive wear and pattern wear are the predominant wear mechanisms, and pattern wear can be seen as the emergence and propagation of cracks. With an increase of the blade tip velocity, both of the final incursion depth and wear mass loss of seal rubber exhibit growth trends. The gradual changes of rubbing forces with an increase of rubbing time are the characteristic of abrasive wear, and force curves with unstable mutations are a reflection of pattern wear. At a constant incursion rate of 100 lm/s, the maximum values of interaction forces decrease first and then grow with an increase of the blade tip velocity, and the blade tip velocity of 150 m/s becomes the cut-off point between abrasive wear and pattern wear.展开更多
基金the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financially supporting one of the authors (M.A.F.)the Instituto de Engenharia Nuclear (IENCNEN)+1 种基金Programa de Engenharia Mecanica (PEM-COPPE/UFRJ)for their invaluable help for the development of the research
文摘Thin Layer Activation is a nuclear technique that has key advantages over other wear measuring techniques for mechanical systems,especially for in site experiments on equipment important to safety in nuclear plants.Still,it incurs radioactive dose and,thus,must be proved radiologically safe before use,otherwise,the utilization of this technique may be hindered inviable.Proving said technique is safe previous to any operational/monetary cost is key,providing a methodology for this early assertion is the main contribution of this work—here,only non-occupationally exposed individuals are considered.This work offers a methodology,through a case study,to ascertain the Thin Layer Activation parameters to obtain safe levels of radioactive dose while maintaining statistically reliable results.This methodology consists of using simulations,through the Monte Carlo Method,to obtain the floors and ceilings for the previously mentioned activation parameters based on operation and work conditions on site.
基金supported by the Fundamental Research Funds for the Central Universities (No. 2013XZZX005)
文摘Abradable seal rubber has been widely used in aero-engine fans to improve their efficiency by reducing the clearance between rotating and stationary components. To investigate the high-speed scraping behavior between a vulcanized silicone rubber and a Ti-6Al-4V fan blade and evaluate the abradable performance of seal rubber, abrasion tests were conducted at a blade tip velocity of 50–300 m/s with an incursion rate of 100 lm/s. The influences of the blade tip velocity on the wear mechanism and interaction forces were specially analyzed. It is shown that abrasive wear and pattern wear are the predominant wear mechanisms, and pattern wear can be seen as the emergence and propagation of cracks. With an increase of the blade tip velocity, both of the final incursion depth and wear mass loss of seal rubber exhibit growth trends. The gradual changes of rubbing forces with an increase of rubbing time are the characteristic of abrasive wear, and force curves with unstable mutations are a reflection of pattern wear. At a constant incursion rate of 100 lm/s, the maximum values of interaction forces decrease first and then grow with an increase of the blade tip velocity, and the blade tip velocity of 150 m/s becomes the cut-off point between abrasive wear and pattern wear.
