Suppose that, instead of using a P.D. pump in Example 10.2, we used a centrifugal pump, which for 200 gal / min had a reported NPSHR of 10 ft. What would be the maximum elevation above the sump at which we could place the pump, assuming that we have a way to prime it? The NSPHR is for the pump only, not including the friction in the lines. There is no inlet valve like that in Example 10.2.answer is 11.4ft Example 10.2. We wish to pump 200 gal / min of water at 150°F from a sump. We have available a P.D.pump that can reduce the absolute pressure in its cylinder to 1 psia. We have an */ g (for the pipe only) of 4ft. The friction effect in the inlet valve may be considered the same as that of a sudden expansion (see Sec.5.5) with inlet velocity equal to the fluid flow velocity through the valve, which here is 10 ft / s. Theatmospheric pressure at this location is never less than 14.5 psia. What is the maximum elevation above thelowest water level in the sump at which we can place the pump inlet?The lowest pressure we can allow in the cylinder (P2) is 3.72 psia, the vapor pressure of water at 150°F. Ifthe pressure were lower than this, the water would boil, interrupting the flow. The density of water at 150°F is61.3 lbm/ft³. Thus,hmax(14.5 -3.7)lbf/in²61.3 lbm/ft³ 32.2 ft/s²144 inft²lbm . ft(10 ft/s)²-32.24 ftlbf.2.32.2 ft/s²= 25.4 ft - 1.6 ft - 4 ft = 19.8 ft = 6.04 m(10.B)

Answered: Image /qna-images/answer/4d5163d3-cc29-4dfc-8247-c3782dc2e9c9.jpg

Answered: Example 10.2. We wish to pump 200 gal /…

Introduction to Chemical Engineering Thermodynamics

8th Edition

ISBN:9781259696527

Author:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart

Publisher:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart

Chapter1: Introduction

Section: Chapter Questions

Problem 1.1P

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Suppose that, instead of using a P.D. pump in Example 10.2, we used a centrifugal pump, which for 200 gal / min had a reported NPSHR of 10 ft. What would be the maximum elevation above the sump at which we could place the pump, assuming that we have a way to prime it? The NSPHR is for the pump only, not including the friction in the lines. There is no inlet valve like that in Example 10.2.

answer is 11.4ft