Minimum baffle height should be ______________?
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Answer: B. Twice the impeller diameter
Explanation
To ensure adequate baffling and mixing in stirred tanks, the minimum baffle height is typically set to twice the impeller diameter. Option B correctly identifies twice the impeller diameter as the standard minimum height for mixing baffles. Proper baffle height prevents central liquid swirling and promotes vigorous top-to-bottom fluid turnover. Baffles are vertical metal plates mounted against the inner walls of agitated vessels to disrupt swirling vortexes. Standard tank design configurations usually specify four baffles spaced evenly around the cylindrical tank circumference. Impeller diameter serves as the primary characteristic dimension used to scale all internal tank mixing geometries.
Options A, C, and D propose baffle dimensions that fail to provide the required flow disruption in agitated vessels. A baffle height equal to the impeller diameter is too short to control vortex formation in deep stirred tanks. Relating baffle height to tank diameter or total tank height incorrectly ignores the critical role of impeller sizing.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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