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	Q: In turbulent flow, how large are the three components of flow for baffled and unbaffled tanks?
	A: That depends on the impeller type. For a flat bladed paddle in an unbaffled tank, Nagata showed that the tangential component of flow is as much as 75-80% of the tip speed (near the impeller). Nagata also showed that at the bottom and near the top, the tangential component was still as high as 70% of the tip speed. Now that's a vortex!

Put in baffles and Nagata found that the tangential flow component went down to about 25% of the tip speed between the baffles and the blade tips. He still determined about 80% of the tip speed at about 80% of the blade diameter at the impeller height.

Nagata also showed that the radial component increased by a factor 4 with the baffles!

Bernd Hoefler, Siegfired Buhlmann, and Bernd Lohr (1979) did a beautiful job of documenting the three components of velocity for a fully baffled tank and 4 different types of impellers: RT, PR, Ekato-MIG, and a very tall RP. They basically confirmed Nagata on the RP. They found the maximum tangential velocity right out at the tip of the paddle's blades at about 53% of the tip speed, and then dropping off dramatically. They also found v(radial,max) = 37% and v(axial,max) = 42% of the tip speed near the wall.

Hoefler, Buhlmann, and Lohr also showed how good a down-pumping Pr is in translating tangential flow into axial flow. v(axial,max) = 0.45 m/s (at 200 mm above the dished bottom, so about 1/2 D below the impeller. This is about 18% of tip speed. v(radial,max) = 0.2 m/s was at the same spot. v(tang,max) is right at the tip of the blade and is about 0.22 m/s or about 9% of the tip speed. They studied their impellers in a large 1.6 m3 tank: T=1.2 m, D=0.4 m. OB=0.45 m. Z = 1.385 m, 4 baffles, N=120 RPM. TS = 2.5 m/s.

	Q: I am confused. How do you navigate your site? It is so large.
	A: Click on the Help button just below the logo and the site's navigational features are explained.

	Q: Do you offer management consulting services?
	A: Not in the traditional sense of consulting management on managerial issues. We consult on engineering, large-scale reactor operation, and R&D matters that are rooted in mixing of the reactants in reactors and vessels. Our audience may include managers, but our intent is to improve your chemical and biochemical processes, not the way you manage people.

Q: I looked up liquid-gas mixing in the mixing forum and it said very little. Surely there is more to gas-liquid mixing than what you wrote about. It is too vague to be helpful. What's up?

A: The entire Mixing Forum is a work in progress. Instead of waiting till it is complete before publishing it, we made the decision to fill the pages as we go. The Mixing Forum eventually will be a complete web based book on mixing, full of hyperlinks and help links to internal and external sites. The purpose of the book is to make identifying, solving or optimizing mixing processes quick and easy. Basic principals will be provided with links to specific articles, other websites that have a better grasp of that technology or have already published that information, and little programs that illustrate the respective topic. Just because a topic in the Mixing Forum is not complete, shouldn't indicate that Post Mixing cannot be of service or troubleshoot your process now. Email us or fill out a Feedback form if you want to know something before it appears in the Mixing Forum.

This page will be the place where common mixing related questions and questions you may have about Post Mixing will be answered. If you have a question you would like to see answered here, click on Feedback or send an email and you will find the answer here soon. Watch news for announcements of updates to the FAQs.

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