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THE OPENUNIVERSITY OF SRI LANKA
DEPARTMENT OF MECHANICAL ENGINEERINGDIPLOMA IN TECHNOLOGY
MEX3235 THERMO-FLUIDSACADEMIC YEAR 2014/2015ASSIGNMENT 02
INSTRUCTIONS(1) This assignment is based on the course material
in Book 3(2) Answer all questions.(3) Write your registration
number clearly on your answer script(4) Submit your assignments as
stipulated in the specimen format for the tutor marked
assignment.(5) Send your answer scripts under registered cover to
the address given below or put it into the assignment box available
in front of the Mechanical Engineering research lab, science and
technology building.
THE COURSE COODINATORMEX3235DEPARTMENT OF MECHANICAL ENGINEERING
THE OPENUNIVERSITY OF SRI LANKAP.O. BOX 21, NAWALA, NUGEGODA.
(6) Last date of submission 14th June 2015. Strictly no late
submissions will be accepted due to any reason. .
1) a) A uniform film of oil 0.13 mm thick separates two discs,
each of 200 mm diameter mounted co axially. Ignoring edge effects,
calculate the torque necessary to rotate one disc relative to the
other at a speed of 7rev/s if the oil has a viscosity of 0.14
Pas.
b) Calculate the Gauge Pressure at point A in Figure Q1 (b)
Figure Q1 (b)2) A 450 reducing bend is connected in a pipe line
the diameter at the inlet and outlet of the bend being 600 mm and
300 mm respectively. Find the force exerted by water on the bend if
the intensity of pressure at the inlet to bend is 8.829 N/cm 2 and
rate flow of water is 600 liters / sec.
3) A sheet piling holds fresh water and salt water (relative
density = 1.035) on either sides of it as shown in Figure Q3. Find
the moment about the base M of the resultant force per unit length
of filing?
Figure Q3
4) A centrifugal pump is required to deliver 50 l/s of water to
a height of 30 m through a 100 m long pipe of 150 mm diameter. The
inlet losses in the suction pipe are estimated to be 0.35m.
Assuming an overall efficiency 70% and taking friction coefficient
as 0.015 for the pipe line , determine the power required to drive
the pump.
5) A venture section of a pipe develops a low pressure which can
be used to aspirate fluid upward from reservoir as shown in Figure
Q5. Show the exit velocity V2 is just sufficient to cause the
reservoir fluid to rise in the tube up section 1 if
Figure Q5
6) Calculate the flow through each of the pipes of the network
shown in Figure Q6.
Figure Q6
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