Quiz10 - V and Re and / D = (0.00085 ft)/(6/12 ft) =...

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57:020 Mechanics of Fluids and Transport November 19, 2010 NAME Fluids-ID Quiz 10. Water at 20 ° C ( ρ = 1.94 slug/ft 3 and µ = 2.09 × 10 -5 slug/ft s) is to be pumped through 2000 ft of pipe from reservoir 1 to 2 at a rate of 3 ft 3 /s. If the pipe is cast iron ( ε = 0.00085 ft) of diameter 6 in, what horsepower (1hp = 550 ft lbf/s) pump is needed? (Note: g = 32.2 ft/s 2 ) Energy equation: ° 1 ± + ² 1 2 ³´ + µ + ° = ° 2 ± + · ³ ³ + µ ³ + ¸ + ¹ (1) ¹ = º = » ¹ ¼ ² 2 ³´ (2) º = 1.8 log ½¾ ¿ À 3 . 7 Á . ¶¶ + 6 . 9 ÂÃ Ä (3) Solution: Compute V and Re: · = Å Æ = 3 ft 3 Ç ( È 4 )(6 12 ft) ³ = 15.3 ft s ÉÊ = Ë·Ì Í = Î 1.94 slug ft 3 Ï ¾ 15.3 ft s Á ¾ 6 12 ft Á 2.09 × 10 Ð5 slug ft s = 709000 (+2 points) With
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Unformatted text preview: V and Re and / D = (0.00085 ft)/(6/12 ft) = 0.0017, by using the equation (3), = 0.0227 (+2 points) The energy equation (1) and the head loss equation (2), along with p 1 = p 2 = p a , V 1 V 2 0, and h t = 0 (no turbine), yield an expression for pump head: = ( ) + 2 = (120 ft) + 0.0227 2000 ft 6 12 ft 15.3 ft s 2 32.2 ft s = 450 ft (+5 points) Thus, the pump power is = = 1.94 slug ft 3 32.2 ft s 3 ft 3 s (450 ft) = 84332 ft lbf s = 153 hp (+1 point)...
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This note was uploaded on 12/08/2011 for the course MECHANICS 57:020 taught by Professor Fredrickstern during the Fall '10 term at University of Iowa.

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