Question

(a) A pipe (K = 2.07x10° N/m2 dan E = 20.7x10 N/m², C1=1.0) with a length of 2500 mis carrying water from an open reservoir at a speed of 2 m/s. The diameter of the pipe is 150 mm with a thickness of 15 mm. When the valve at the downstream end is suddenly closed, calculate the i) increase of pressure at the valve. ii) time taken for the pressure wave to travel from valve to reservoir. iii) sketch the pressure vs. time at the valve and at the mid-point of the pipeline after the valve closure for two wave period. iv) if the valve is completely closed in 8 seconds, what is the difference in the calculation above?

Answer 1

ANNON The given oda (KW.01 X109 x 10Nim? E = 20 7 X 109 N/m²; c=1.0. tength of pipe : 2500 m s velocity - 2015 The diamehor or pipe - 150 mm Thicknek of pipe e 15 mm E When the value closed suddenly, Inweise of pressure of the value :- Jocrease velocity in pressure ap change on Sap = sco f = Density of fluid -chang in fluid velocity - Sonic velocity is the pipe V с S [/K + /e page: 1

mis s het D - 1000 + 0.15 어 2.67x10" 20 741090.015 c=1438 103 m/s Ap=8co > 1000 x 1436.03X (2-0) Ap= 4 Bly 09 x103 N/m2 6r) pascal 24314.09 xlo® /m (1) Time taken for pressure ware_to toa vel forms ap value to resesvior å 2x2500 I Tc = C 143603 To s3.476 seconds (iii) Time (Ta) Time (Ta) = 8 seconds Critical Time To = 3.47 seconds. .. Ta YTc gradul closure p = SL 1000 X 2X 2500 Тc pascal 3.47 pa pressure for sudden closure = 4314:09 x103 pasul pressure for gradual closure = 14.409 No for time pal Selce.