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In the post-cooling pumping plant, each pipe coil is supplied at a flow rate of approximately:
Answer & Solution
Correct answer: B.
1. The chosen flow rate must keep water flow turbulent inside the embedded pipe.
2. Turbulent flow drives the heat-transfer coefficient up, accelerating cooling.
3. The unit prescribes 15 to 17 litres per minute per coil.
4. This rate produces a velocity about four times the minimum turbulent threshold.
5. The lower and higher flow rates would either be laminar or wasteful.
_Source: IGNOU Concrete Technology, Unit 7 "Concreting Equipment" (Mixers, Cableways, Batchers, Buckets, Pre/Post Cooling)._
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