HYDROLOGY & HYDRAULIC ENGINEERING I LABORATORY
: BERNOULLI’S THEOREM APPARATUS
: 10th December 2009
: 17th December 2009
TABLE OF CONTENT
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Equipment/ description of experimental apparatus
Data and observation
The title of this experiment is the Bernoulli’s theorem apparatus. The objective of this experiment is to determine the relationship between pressure head, velocity head, and static head and compare it with Bernoulli’s Theorem. The total head of flowing liquid between two points remain s constant provided there is no loss due to friction no gain due to application of outside work between the two points. So basically the apparatus used for this experiment consist of a venture tube with different diameter at certain part, 8 tubes of water manometer, a rotameter, stainless steel tube and a stop watch to record the time of the water flow.
The procedures are simple, after connecting the hydraulics bench outlet to the test set, the pump is started. Then adjust the flow rate to 10, 15, 20 L per minute. The flow rate and readings for each manometer should be taken and recorded in the table provided. The total head at any point is indicated on tube no.7.
As for the result, we need to obtain the time needed for the flow to fill up 4L. Then we can calculate the flow rate followed by the velocity of the flow at any point. With the velocity of the flow for each point are known, thus we can calculate the velocity head for each point. As for the static head value is taken from the manometer readings. We can observe that even point 1 and point 8 have the same diameter but the flow rate manometer readings might differ a little which is due to the friction loss along the venture tube. There might be some error occur in this experiment as the valve in this apparatus used contain some defect which will affect the result of the experiment.
After conducting this experiment, we can conclude on the statement of Bernoulli’s Theorem that relates between velocity head and static pressure head, where the increase of velocity head is compensated by a reduction in the static pressure.
The purpose of this experiment is to investigate the relation of pressure head, velocity head and static head then compare with Bernoulli’s Theorem. Besides, this experiment also aims to determine the total head and the friction loss between two points in the Venturi tube with same cross sections.
Bernoulli’s Theorem States ‘The total head of flowing liquid between two points remains constant provided there is no loss due to friction no gain due to application of outside work between the two points. Total head (HL) of flowing liquid is made up of Elevation Head or Static Head (Hs). Pressure Head (Hp) and Velocity Head (Hv), mutually convertible each into the other’s form.
HT = total head
V = velocity
P = pressure
Z = Elevation
G = Acceleration due to gravity
ρ = Density
Thus for point 1 and 2
= + Energy Loss between 1 & 2 …………. (1)
D1 = 28.0mm
D2 = 21.0mm
D3 = 14.0mm
D4 = 16.8mm
D5 = 19.6mm
D6 = 22.4mm
D7 = 25.2mm
D8 = 28.0mm
If the Bernoulli’s tube is horizontal then Z1 = Z2 and if loss between point 1 and 2 is very small, then :
……………………………. (2) or
If point 1 and point 2 are different diameters, then and V1 and V2 are different. This is demonstrated by difference in manometer water levels between point 1 and point 2....
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