Skip to main content

Fluid Mechanics

MICRO MANOMETERS AND INCLINED MANOMETER

Introduction

Micro-manometers and inclined manometers are modified forms of simple U-tube manometer.

Micro-Manometer

Micro-manometer is also known as single column manometers. The construction of a micro-manometer is as follows:

  • One limb of manometer is a tank of large cross sectional area as compared to the cross sectional area of the other limb.
  • This tank acts as a reservoir to hold the manometer fluid.
  • The cross sectional area of the tank is 100 times greater than that of the other limb.
  • When there is change in the pressure in the pipe, there is negligible change in the level of fluid in tank.
  •  This change can be neglected and pressure can be measured as height of liquid in the other column.

It is of two types:

i. Vertical column micro-manometer

ii. Inclined column micro-manometer

1.Vertical Column Micro-manometer



Initially, when there is no fluid flowing in the pipe the level of manometer liquid is at XX. But due to liquid pressure in the pipe the level of manometer liquid moves down from XX to YY in the tank and rises in the right limb to the distance h2 from XX. 

Let,      

ρ1 = density of liquid for which pressure has to be determined

             ρ2 = density of manometer liquid (assume mercury)

             S1 = Specific gravity of liquid for which pressure has to be determined

             S2 = Specific gravity of manometer liquid

             δh = Fall in the level of liquid in the tank

             A = Area of cross-section of the tank

             a = Area of cross-section of the right limb

             h = Pressure head of fluid in the pipe (as head of water)

Let h be the pressure in terms of height of fluid in the pipe.

h1 is the distance from the datum line XX to the centre of pipe

h2is the height of heavy liquid from the datum line XX in the right limb

The rise in the manometer fluid in the right limb will be equal to the fall of level in the tank.

Therefore:

              δhA=a.h2

             

Pressure in the left limb at YY= 

Pressure in the right limb at YY= 

According to Pascals law,

If the cross sectional area of the tank A is very large compared to cross sectional area of the right limb then i.e. A >> a, then,

Ratio of a/A will be zero and the above equation can be re-written as:

2.Inclined column Micro-manometer

  • Inclined manometers are more sensitive than vertical column manometers. 
  • Initially, when there is no fluid flowing in the pipe the level of manometer liquid is at XX. 
  • But due to liquid pressure in the pipe the level of manometer liquid moves down from XX to YY in the tank and rises in the right limb to the distance h2 from XX. 



Let,      

             S1 = Specific gravity of liquid for which pressure has to be determined

             S2 = Specific gravity of manometer liquid

             δh = Fall in the level of liquid in the tank

             A = Area of cross-section of the tank

             a = Area of cross-section of the right limb

             h = Pressure head of fluid in the pipe (as head of water)

h1 is the distance from the datum line XX to the centre of pipe

h2 is the height of heavy liquid from the datum line XX in the right limb

 = length of manometer fluid along the right limb

The rise in the manometer fluid in the right limb will be equal to the fall of level in the tank.

From equation for vertical column micro-manometer we have:

       

And since h2 = l Sin α


Labels:

Comments

Post a Comment

Popular posts from this blog

Fluid Mechanics "Centrifugal Pumps"

Centrifugal Pumps : we'll just cover certain sections of it, it's on your course syllabus. But we'll start off looking at centrifugal pumps .  A very common type of pump. Swimming pool pumps, spa pumps, all kinds of pumps.  Quite a few of them are centrifugal pumps. I thought so. Okay,sometime this quarter, I don't think this early, you're going to run a test on a centrifugal pump in the fluids lab.  And from that test you're going to put together some performance curves for our centrifugal pump.   So, this is how we  test a centrifugal pump.  I'll go through the procedure that we use in our fluids lab.  We have a pump in a circuit with water in it, from a big reservoir.  The water is pumped through here, it goes around, back into the big reservoir.  We have flow meters in the test setup so we know what the flow rate Q is. We have pressure gauges at points one and two. A centrifugal pump is a radial type of a pump.  There's an impeller ...
Post a Comment
Read more

HSC Computer Science Syllabus 2019

HSC Computer Science Syllabus 2019 Computer SciencePaper I  1. OPERATING SYSTEMS : Operating system, services in 0.5, windows 98, Windows NT, LINUX, File systems, Multitasking, Multiprogramming, Memory Management, G.U.I., Security threats, computer Viruses, Worms, Security. 2. Data Structure: Introduction to data structure operation, Algorithmic notations, control structures, Arrays. Representation in memory, Transversing, Deleting, Sorting Printer array, Records in memory using, array. Linked list, Representation in memory.Trees, Binary trees.  3. C++ : Introduction of C++, Arrays, Pointers, references, strings principle of object oriented programming, classes and object, constructors and destructors, operator overloading and type conversions, inheritance, virtual function and polymorphism class. 4. HTML:  Introduction to HTML, advantage and disadvantage of HTML, study of tags, < HEAD> ,  <TITLE>, <BODY>, <P>, < BR>, <UL>, ...
Post a Comment
Read more

First and Zeroth Law of Thermodynamics

 First law Of Thermodynamics; To understand thermodynamics well and to make any calculations in thermodynamics, it is extremely important that we have its basic rules. These are some of the basic laws of thermodynamics.The first law of thermodynamics in  will try to understand about this very useful rule through medium. Heat was not considered a form of energy when thermodynamics was developing. But after some time it was proved that heat is also a form of energy, after that an attempt to find a relationship between heat and work started. Heat and work are two different forms of the same entity, and that entity is called energy. This means that if heat is supplied to a system, it can come out as work, or as work is done on a system, it can come out as heat. While the relationship between heat and work came out, a new term introduced the whole world, which was called internal energy. The first law of thermodynamics shows the relation between heat, work and internal energy. F...
Post a Comment
Read more