Petrochemical Deep Processing Version 2018.12.04
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Participation: Prize 1 Wealth； Correct answer: Reward of 3 wealth points ； Note: This post is valid for 48 hours. https://bbs.hcbbs.com/static/image/hrline/2.gif True or False: If a centrifugal water pump transports 200 tons of water in two hours, then its flow rate is 100 t/h. ( ) Answer: Correct. Your participation is the greatest support for our work. Giving roses to others leaves a pleasant fragrance in one’s own hands. https://bbs.hcbbs.com/static/image/hrline/1.gif https://bbs.hcbbs.com/static/image/hrline/2.gif Note: The answers will be published automatically after two days. ““My Device, My Home” – Large-scale Original Photo Sharing Event (Part 2): https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1868167&extra=page%3D1 Petrochemical Deep Processing Section [Daily Question] Summary Post: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1496481
Wrong, the flow rate should be greater than 100 t/h.
The main performance parameters indicated on the centrifugal pump’s nameplate are values measured under conditions of maximum efficiency when using clean water at 20°C. However, various losses occur during the actual operation of the pump: (1) Volumetric loss – The loss caused by leaks in the pump is referred to as volumetric loss. The ratio of the pump’s power without volumetric losses to its power with volumetric losses is called the pump’s volumetric efficiency ηv. (2) Hydraulic loss: When a fluid flows through the impeller and pump casing, changes in the speed and direction of the flow, along with the presence of a reverse pressure gradient, give rise to circulations and vortices, resulting in energy loss. This type of loss is known as hydraulic loss. The hydraulic efficiency ηh of a centrifugal pump at its rated flow rate is generally between 0.8 and 0.9. (3) Mechanical losses: The losses caused by the friction between the high-speed rotating impeller and the liquid, as well as the mechanical friction at bearings, shaft seals, and other locations, are referred to as mechanical losses. The mechanical efficiency ηM is generally between 0.96 and 0.99. Therefore, 200 tons of water were delivered in two hours, so the designed flow rate of the pump should be greater than 100 t/h.