Power consumption during turbulent fluid agitation scales with the ______________ of the liquid?
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Answer: D. Density
Explanation
Turbulent fluid agitation power numbers remain constant, making power consumption directly proportional to fluid density. In fully turbulent regimes, inertial forces dominate viscous forces within the agitated liquid system. Fluid density directly scales the momentum transfer required by the rotating impeller blades during mixing. Agitation power characteristics are typically correlated using dimensionless numbers like the Reynolds and Power numbers. Turbulent flow in stirred tanks occurs at high impeller Reynolds numbers exceeding ten thousand. Dimensional analysis confirms that fluid viscosity has no significant effect on power in pure turbulence.
Chemical engineers use these scaling laws to design large industrial bioreactors and chemical mixing vessels. Accurate power predictions prevent motor overload and ensure adequate blending of dense industrial process slurries. Changes in batch composition and density require careful recalculation of operating power requirements. Option A is incorrect because viscosity influences power only in the laminar flow regime, not turbulent. Option B is irrelevant since thermal conductivity governs heat transfer rather than mechanical agitation power. Option C affects droplet formation and interfacial phenomena rather than bulk turbulent power consumption.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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