Question

..Liquid water at 20°C flows through an inclined Venturi meter at a flow rate of 0,12 m²/s. The inside Assume no head loss from point 1 to point 2. A mercury manometer is used to measure the pressure ipe diameter is reduced from 32 cm at point I to 16 cm at point 2. Point 1 is 28 cm lower than point 2. difference, as shown in the sketch. (a) Calculate the Reynolds number of the flow in the pipe at point 1. What does this result indicate? (b) Calculate the pressure difference, p,- 2. (4 marks) (c) Calculate the height of mercury (hm) in the manometer. (4 marks) (2 marks) Az=28 cm -32 cm

Answer 1

- at zoº for water e= 998 kg/m3 given u=1.902x10 3 Pais a=0.12 m/s Qa Avia A2V. , V. = I (0.322) => 1 = 1.492 m/s Vo - 0.12 I (0.162) = ₂ = 5.968 mis 0-12 @ 6 and Z₂-Z, = 0.28 m. Reynolds number Recevo)= 998*1.492 *0:32 1.002 x 103 Re=475558.78 (Turbalent) Hlow Apply Bernoullis equation bio point o E 7 + 12 + 24 = ++22 eg zg Р. - P. =212) + Z₂-Z, Perem os (5-9682_1-492) + 0.28 = 1.982 Pi-P2 = was 99889.& 1 x 1.982 = 18, - P2 = 19.44 kport 2x9-81

= 1.982 0 Head in water coloumn => P- ta the manometer a hasa hom ( em 1) 1.982 = hm (13550 -1) by hm = 0.1575 m of Hg. I