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Writer's pictureTaliya Mammadhasanzada
Aug 9, 20204 min read

Fluid of Flow 2 🧚🏻

Warm greetings to all in the 7th post on #Day6 ! Today we are going to continue to Fluid of flow 2🤹🏻, our main focus will be an fluid in motion, continuity, water hammer and energy of a fluid in motion. Here we go 🤩🚀,



The Fluid in Motion🧙🏻‍♀️

🧪When a fluid flows through a duct or over a surface, the velocity over a plane at right angles to the stream is not normally uniform. The variation of velocity can be shown by the use of streamlines which are lines so drawn that the velocity vector is always tangential to them. The flowrate between any two streamlines is always the same. Constant velocity over a cross-section is shown by equidistant streamlines and an increase in velocity by closer spacing of the streamlines. There are two principal types of flow which are discussed in detail later, namely


  • laminar and

  • turbulent flow.


In laminar flow, movement across streamlines occurs solely as the result of diffusion on a molecular scale and the flowrate is steady. In turbulent flow the presence of circulating current results in transference of fluid on a larger scale, and cyclic fluctuations occur in the flowrate, though the time-average rate remains constant. A group of streamlines can be taken together to form a streamtube, and thus the whole area for flow can be regarded as being composed of bundles of streamtubes.

🔗Figures 2.3, 2.4 and 2.5 show the flow patterns in a straight tube, through a constriction and past an immersed object.





In the first case, the streamlines are all parallel to one another⚙️, whereas in the other two cases the streamlines approach one another as the passage becomes constricted, indicating that the velocity is increasing📈.



Continuity💥

⛓Considering the flow of a fluid through a streamtube, as shown in Figure 2.6,


🖇then equating the mass rates of flow at sections 1 and 2:



It is seen that it is important to be able to determine the velocity profile so that the flowrate can be calculated, and this will be done in the future's pots. For laminar flow in a pipe the mean velocity is 0.5 times the maximum stream velocity which occurs at the axis. For turbulent flow, the profile is flatter and the ratio of the mean velocity to the maximum velocity is about 0.82


Water Hammer💧🔨

🛠If the flow rate of a liquid in a pipeline is suddenly reduced, such as by rapid closure of a valve for example, its rate of change of momentum can be sufficiently high for very large forces to be set up which may cause damage to the installation. In a pipeline carrying water, the resulting pressure wave may have a velocity as high as 1200 m/s. The behavior of the pipe network will be influenced by a large number of factors, including the density and the bulk modulus of elasticity of the liquid, Young's modulus for the material of the pipe, and the design and layout of the installation. The situation can arise with the flow of any liquid, but it is usually referred to as water hammer📿



on account of the characteristic sound arising from water distribution systems.


Energy of a Fluid in Motion🧨

🧲The total energy of a fluid in motion is made up of a number of components. For unit mass of fluid and neglecting changes in magnetic and electrical energy, the magnitudes of the various forms of energy are as follows.



  • Pressure energy🔑

This represents the work which must be done in order to introduce the fluid, without change in volume, into the system. It is therefore given by the product

✅P*v,

where P is the pressure of the system and v is the volume of unit mass of fluid.




  • Potential energy🧯

The potential energy of the fluid, due to its position in the earth's gravitational field, is equal to the work which must be done on it in order to raise it to that position from some arbitrarily chosen datum level at which the potential energy is taken as zero. Thus, if the fluid is situated at a height Z above the datum level, the potential energy is

✅Z*g,

where g is the acceleration due to gravity which is taken as constant unless otherwise stated


  • Kinetic energy💡

The fluid possesses kinetic energy by virtue of its motion with reference to some arbitrarily fixed body, normally taken as the earth. If the fluid is moving with a velocity u, the kinetic energy is

✅u^2/2 (u square per 2).


References 📖

  1. Coulson&Richardson, Chemical Engineering Design Volume 1

  2. DODGE, B. F.: Chemical Engineering Thermodynamics (McGraw-Hill, New York, 1944).

  3. DE NEVERS, N.: Fluid Mechanics for Chemical Engineers, 2nd edn (McGraw-Hill, New York, 1970).

  4. DOUGLAS, J. F.: Solution of Problems in Fluid Mechanics (Pitman, London, 1971).

  5. MASSEY, B. S.: Mechanics of Fluids, 6th edn (Chapman and Hall, London, 1989).

  6. MILNE-THOMSON, L. M.: Theoretical Hydromechanics (Macmillan, London, 1968). SCHLJCHTING, H.

  7. Boundary Layer Theory, 5th ed (McGraw-Hill, New York, 1968).

  8. SMITH, J. M. and VAN NESS, H. C.: Introduction to Chemical Engineering Thermodynamics, 5th ed (McGrawHill, New York, 1995).

Additional Resources 🧪

🔑You can get deep insight about Process/Chemical Engineering from these sources😉:

  1. https://t.me/chemical_environmental- Discussion group related to Chemical Engineering Problems

  2. https://t.me/chemicalengineeringworld_cew- Everything related to Chemical Engineering

  3. https://t.me/ebookgate- Chemical Engineering E-books (Telegram Channel)

  4. https://www.youtube.com/channel/UCqioh32NOJc8P7cPo3jHrbg- Piping Analysis

  5. https://www.youtube.com/channel/UCQfMyugsjrVUWU0v_ZxQs2Q -Mechanics of engineered devices

  6. http://chemicalengineeringguy.com/- suggests a wide range of courses in Chemical engineering (you can find free courses on topic of Aspen HYSYS, Aspen Plus)

  7. https://www.youtube.com/user/LearnEngineeringTeam- suggests working principles of every engineered devices, equipment and etch.

  8. https://www.youtube.com/channel/UCR0EfsRZIwA5TVDaQbTqwEQ- suggests great information about pumps, compressors with animation.


🔌Today we have already learned about whole Flow of Fluid part 2, Water Hammer, Continuity Equation, Energy of a Fluid in Motion, now time to say goodbye👋🏻 until tomorrow and Stay tuned for more content 😉🌝✨!



✏️Note: If you need one of those books or links, you can contact me via my email or LinkedIn profile.



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