Question

An orifice meter with orifice diameter 15cm is inserted in a pipe of 30cm diameter. The
pressure difference measured by a mercury oil differential manometer on the two sides
of the orifice meter gives a reading of 50cm of mercury. Find the rate of flow of oil of
sp.gr.0.9 taking the coefficient of discharge as 0.64.​

Answer 1

Explanation:

Given An orifice meter with orifice diameter 15 cm is inserted in a pipe of 30 cm diameter. The pressure difference measured by a mercury oil differential manometer on the two sides of the orifice meter gives a reading of 50 cm of mercury. Find the rate of flow of oil of sp.gr.0.9 taking the coefficient of discharge as 0.64.

• Diameter of orifice d1 = 15 cm = 0.15 m  = 0.15 / 2  
• Diameter of pipe d2 = 30 cm = 0.3 m = 0.3 / 2
•  So Area A1 will be π r^2 = π / 4 x (0.15)^2
•                                        = 0.0176625
•       Area of pipe A2 will be = π / 4 x (0.3)^2
•                                          = 0.07065
•  Specific gravity of oil is 0.9
• So differential manometer measured will be x = 50 cm of mercury
•                                                                                   = 0.5 m
• Therefore Differential head h = x (Sp gr of mercury / Sp gr of oil – 1)
•                                               = 0.5 (13.6 / 0.9 – 1)
•                                               = 7.05 m  
• Now rate of flow through an orificemeter will be  
•                                Q = Coef of discharge x A1 A2 x √2gh / √A2^2 – A1^2
•               = 0.64 x 0.0176625 x 0.07065 x √2 x 9.81 x 7.05 / √(0.07065)^2 – (0.0176625)^2
•                    = 0.1374 cu m / sec
•                         = 137.4 litres / sec

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https://brainly.in/question/11634018