JNTU exam papers B -Tech I Sem – Fluid mechanics for chemical engineering -November 2008

JNTU II B.Tech I Semester Supplimentary Examinations, November 2008

FLUID MECHANICS FOR CHEMICAL ENGINEERING

(Chemical Engineering)SET-4

 

 

1. A continuous gravity decanter is to separate chlorobenzene, with a density of 1109

kg/m3, from an aqueous wash liquid having a density of 1020 kg/m3. If the total depth in the separator is 1 m and the interface is to be 0.6 m from the vessel floor,

(a) what should the height of the heavy-liquid overflow leg be;

(b) how much would an error of 50 mm in this height affect the position of the interface?

 

2. (a)Explain the behavior of Non-Newtonian fluids with the help of plot and give examples

(b) Differentiate between incompressible and compressible fluids. Give examples.

 

3. (a) Define ’Equivalent diameter’ for fluid flow through ducts of noncircular diameter.

(b) Calculate the hydraulic mean diameter of the annular space between a 4 cm and 6 cm tubes.

(c) Draw velocity profile for laminar flow in a circular pipe.

 

4. Air enters a convergent – divergent nozzle at a temperature of 555.6K and a pressure

of 20atm. The throat area is one-half that of the divergent section assuming the Mach number in the throat is 0.8,what are the values of the following quantities at the throat ; Pressure, temperature, linear velocity, density and mass velocity.

 

5. (a) Urea pellets are made by spraying drops of molten urea into cold gas at the top of separator of a tall tower and allowing the material to solidify as it falls. Pellets 6mm in diameter are to be made in a tower 25m high containing air at 200C.T e density of urea is 1330Kg/m3.What would be the terminal velocity of the particle assuming free settling conditions.(?gas= 0.018CP,?gas=1.21kg/m3)

(b) Discuss the following:

i. Kozeny Carman Equation

ii. Burke- Plummer Equation.

 

6. (a) A catalyst tower of spherical particle diameter 4.0 mm is to be fluidized with water at 250C. The original unexpanded bed was 0.7m ant the voidage associated is 0.37.The height of the expanded bed is 2 m. Find the voidage for the expanded bed.

 

(b) Distinguish between aggregative fluidization and particulate fluidization with applications.

 

7. Discuss the working, merits and demerits of any four common types of valves used in process industry.

 

8. (a) Explain the working of a reciprocating compressor.

(b) Derive the expression for the work done for an isothermal compression.

 

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