AFT Blog
The term transient cavitation is thrown around frequently when talking about the effects that transient events have on piping systems. It is widely and correctly understood to be something that can be harmful to pipes and pipe system components, but how to predict and calculate transient cavitation is not something that is as equally understood. In...
Vacuum breaker and air valves are useful tools in the industry for protecting pipelines against vacuum or near vacuum conditions. High points in the pipe can be susceptible to these low-pressure conditions during surge events, as pressure waves moving through the system cause a sudden pressure upsurge or downsurge. AFT Impulse can help engineers to...
I am sitting on an airplane at this moment somewhere over the Atlantic Ocean and I am excited. Something that has been in the works for 22 years will happen next Monday, July 16 in Prague, Czech Republic. That is where the ASME PVP 2018 Conference will happen and I get to make a presentation.
Last year I helped AECOM, an AFT customer and AFT Impulse user, develop a set of pragmatic internal design documents for their project on handling radioactive fluid transport. Two of these documents provided their engineers guidance on interpreting and applying transient cavitation predictions.We proposed these two documents to the ASME PVP Division and they liked them enough to allow us to publish two new papers at their conference. I will be presenting these papers on behalf of AECOM and AFT.
AFT Impulse 5 now includes a second cavitation model option: The Discrete Gas cavity Model (DGCM). So, what is it and how is it different from the existing cavitation model? This article will provide a very high level overview. The method of characteristics (the finite difference basis for 1D transient flow modeling) assumes a constant wave speed for each pipe, from time step to time step. There are, however, many things that would cause a change in wave speed; cavitation being one the most significant. A change in wave speed will have a dramatic effect on the pressure spike that occurs...