MixSim: Retreat Curve impeller: How do I tell the impeller diameter?
I've been given the task to simulate a retreat curve impeller with a given diameter. In MixSim, there is no option to enter the impeller Diameter. What can I do? Try the following:  activate the check box (toggle option) "FixZoneDimensions?". This will advise MixSim to display the (now fixed) MRF zone dimensions in the preview graphics.  Modify the definition of the "RotZoneDia" parameter: Remove the " + [BladeThickness]" from the definition, so that the whole definition reads simply "[Diameter]".  By this, MixSim will calculate, display, and visualize the impeller diameter as the diameter of the MRF zone boundary (parameter "RotZoneDia").  Now play with the other parameters. You will find that... + The "Blade Length" is the length of the blade along its *curved* center line, from the hub surface to the blade tip. + If you set the blade curve radius to a very high value (100 meters or 1000 meters), the blade becomes (almost) straight, and the impeller diameter equals almost exactly the expression "2 * blade_length + hub_diameter". A small deviation in this equation results from MixSim accounting for the blade *thickness* also. This becomes obvious when you reduce the "Blade Curve Radius" again. + The automatic calculation of the impeller Diameter (which we display and visualize through the "RotZoneDia" parameter) does currently NOT take into account the.. o Retreat Angle and... o Blade Angle ...parameters.  Please REMEMBER to add " + [BladeThickness]" to the equation defining the "RotZoneDia" parameter. Also, if you are using the "Retreat Angle" or the "Blade Angle" parameter, please consider doublechecking the calculated MRF zone dimensions by temporarily fixing and viewing them in the preview graphics.  Finally, consider releasing the "FixZoneDimensions?" check box (toggle button) again, so that MixSim can grow the MRF zone when there is sufficient space available for that. 

