Fluid Dynamics Professional for Mixing Device

I am designing a vessel for vortexing water and have the following specific questions. I am not looking for design input beyond these parameters. 1. Blade length In a cylindrical vessel of 20cm internal diameter containing 4 litres of water, how long would two ceramic aerofoil blades need to be, mounted at the base of the vessel, to reliably produce a full-depth vortex reaching from base to surface — while avoiding toroidal flow? 2. Blade angle At what angle would those blades need to be pitched so that anticlockwise rotation produces upward water flow and clockwise rotation produces downward water flow? 3. Vessel height How high would the walls of a 20cm diameter vessel need to be to prevent water surface contact with a lid during full vortex operation at your recommended RPM? 4. RPM At the blade length and angle you recommend, what RPM reliably produces a full-depth vortex in a vessel of these dimensions? 5. Base edge geometry Is a flat base with rounded bottom edges or sharp cornered bottom edges more conducive to full-depth vortex formation in a cylindrical vessel?