AFT Blog
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...
AFT Applications have the ability to display the output in different languages. We supply files for French and Spanish with our installation which should be used. Other language files can be created using the language.dat file template. To select a new language select Output Language from the Tool menu and then select the language you would like to use. Once a new language is selected the Output Control will reflect the output parameters in that language. When the model is run and the results will be displayed in the Output tab in the selected language. The Graph Results and Visual Report...
You have just finished designing your system and built a model of your system in AFT Fathom and have convinced your team and the client that the system will achieve all the desired pressures, flow rates, and temperatures. The next big question is, “How much will this system cost?” With AFT Fathom, you have the ability to answer that question in great detail! You can easily determine the full cost of pipe materials and system components! Not only that, but you can quickly figure out how much it will cost to install and operate the entire system! You will even be...
One of the many new features in AFT Impulse is the ability to show junction locations in profile plots. This can be enormously helpful when analyzing large, complicated systems. When enabled, all junction locations are identified by a vertical bar with a junction ID flag at the top. To show junction locations, click on the button in the toolbar.Show Junction Locations will also work for animations.
Applied Flow Technology is proud to release a new version of AFT Impulse, now at version 5. AFT Impulse 5 encapsulates all of the new interface and navigational enhancements from AFT Fathom 8, as well as a considerable breadth of new and improved technical features. One such feature is our newly enhanced Relief Valve Junction. A relief valve can still be modeled as Internal, Exit, or Inline Exit, but we now offer four unique opening/closing profiles as well. With these new profiles, you can now directly model many specialty valves which were previously difficult to model accurately! Another very useful enhancement...
AFT Fathom can EASILY size valves AND orifice plates with a SINGLE Control Valve junction! There is no need to perform strenuous hand calculations to determine a valve Cv or an orifice diameter. Just specify the system boundary conditions, pipe input properties, and the desired flow rate (or pressure) and AFT Fathom will calculate the Cv, K factor, and equivalent orifice diameter/area for you all at once! Figure 1 illustrates a control valve junction at the location of a valve or an orifice plate. For known flow, use a Flow Control Valve (FCV). For known upstream pressure, use a Pressure Sustaining...
AFT Arrow uses Newton iteration to find a simultaneous solution for all junction pressures. Well, maybe not all junctions. When “Use Exhaustive Tolerance Criteria” is NOT selected, AFT Arrow will only check junction pressures that find their way into the solution matrix. The AFT Arrow solver builds a matrix of equations based on the number of flow splits in the model. Each flow split must have a common pressure that is consistent with the flow and pressure drop in all of the connected pipes. Finding the right pressure for each flow split can become rather tricky. To find the pressure using...