Page 18 - BASIC CONCEPTUAL OF THERMOFLUID
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CHAPTER 2: FLUID APPLICATION
The pressure, at the bottom of the cylinder will be due to the weight of the liquid contained in the cylinder.
Let this pressure to be P.
ℎ ℎ
=
ℎ
ℎ
= = ℎ , ℎ =
= ℎ
Example 2.1
What is the pressure experienced at a point on the bottom of a swimming pool 9 meters in depth? The density of
water is 1000 kg/m³.
Solution:
= × × ℎ
= 1000 × 9.81 × 9
= 88.290
2.2 Application of Pascal Law and Hydraulic Jack
2.2.1 Pascal’s Law
A change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points
in the fluid. Pressure exerted on a fluid in an enclosed container is transmitted equally and
undiminished to all parts of the container and acts at right angle to the enclosing walls.
Alternate definition: The pressure applied to any part of the enclosed liquid will be transmitted
equally in all directions through the liquid.
= ℎ
2.2.2 The Hydraulic Jack
Hydraulic jack is such a hydraulic system. A hydraulic jack is used to lift heavy loads, such as the ones
used by auto mechanics to raise an automobile. It consists of an incompressible fluid in a U-tube fitted with
a movable piston on each side. One side of the U-tube is narrower than the other. A small force applied
over a small area can balance a much larger force on the other side over a larger area (Fig. 2 as below).
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