JNTU,B.Tech I Semester FLUID MECHANICS, November 2008

JNTU,B.Tech I Semester FLUID MECHANICS, November 2008

(Chemical Engineering)




1. Derive the equation for the interfacial height in a gravity decanter. [16]


2. (a) A pipe line tapers from 10cm dia to 4cm dia. The quantity of water flowing

the pipe is 0.15m3/sec. Calculate the average velocity at the two sections.


(b) Write one dimensional equation of continuity. [6]


3. Show that for a Newtonian fluid flowing in laminar flow through a pipe , the ratio

of average velocity to maximum velocity 0.5. [16]


4. (a) Calculate the hydraulic mean diameter of the annular space between a 40 mm

and a 50 mm tube. [4]

(b) A liquid having density of 0.97 gm/cc and a viscosity of 0.347 cp is flowing

through a pipe of diameter 10.2 cm with a velocity of 75 cm/s. Calculate the

Reynold’s number. [4]

(c) A steel pipe 2 ft in diamter carries water at about 15 ft/s. If the pipe has a

roughness of 0.0003ft, could he capacity be increased by inserting a smooth

plastic liner that reduces the inside diameter to 1.9 ft? Calculate the change in

pressure drop for the same flow and the charge in capacity for a fixed pressure

drop. [6]


5. Explain adiabatic compression. Derive the equation for shaft work for adiabatic

compression. [16]


6. Derive Ergun equation to calculate pressure drop through bed of solid particles.



7. Estimate the minimum fluidization velocity for a bed of particles fluidized by water

using the following data: Diameter of the particle = 120 ?m; sphericity =1; density

of the particle = 2500 kg/m3; density of water is 1000 kg/m3 ; minimum porosity

is 0.45; viscosity of water is 0.001 kg/m s. [16]


8. Sulphuric acid of specific gravity 1.3 is flowing through a pipe of 5 cm ID . A thin

tipped orifice os 1cm diameter is fitted in the pipe and the differential pressure

shown by the mercury manometer is 10 m .Calculate the weight of acid flowing per

hour . Take the orifice coefficient as 0.61. [16]


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