# 3 is the elevation (in meters) of point i,

3 TO DETERMINED THE HEAD LOSSES DUE TO PIPE FITTING AND BENDING3.1 OBJECTIVE: The equipment measures the pressure drop at various flow rates when flow through different pipe bends and fittings. It is used with hydraulic bench (separately supplied) All bends and fitting are connected in series with pressure tapping on both sides of each device. A water manometer with a vent value and a hand air pump is connected to these tapping’s.   3.2 APPARATUS: 1 Stop watch.  2 Bend sand fittings apparatus. 3 Hydraulic bench. 4 Technical Data: 5 Pipe Diameter:                       20mm or ¾ in approx. 6 Enlarged pipe diameter:      35mm or 1 ¼ in approx. 7 Bends:                                       90o Meter bend, 90o small radius bend, 90o large radius 8 Fitting:                                      90o Elbow, 45o elbow, sudden expansion, sudden contraction 9 Water manometer:                 8tubes×450mm×1mm graduation. 3.3 PROCEDURE: • Before the test:• Put the set on the hydraulic Bench, Adjust the leveling screws and connect water supply to the bench outlet.  Close Pressure relief valve at the manometer top chamber. Open the test set flow control valve. 3.3.1 Start the Test: Start the hydraulic bench pump and adjust flow to about 20 lpm and adjust the test set flow control valve to remove all air from the piping system by lowering the flow rate to about 5 lpm. Adjust manometer levels to mid-range by manipulating flow control valve at the out let or hand air pump to the manometer top chamber. Records all manometer readings and flow rate using measuring tank and stop watch. Increase flow rate by 2.5 lpm at a time and record manometer readings and flow rates, until maximum flow is reached. 3.4 THEORY• The energy balance between two points in a pipe can be described by the Bernoulli equation, given by• where pi is static pressure (in Pa) at point i, ? is specific weight of the fluid (in N/m3), zi is the elevation (in meters) of point i, Vi is the fluid velocity (in m/s) at point i, g is the gravitational constant (in m/s2), and hL is head loss (in meters).  The term pi/? is referred to as the static head; zi is the elevation head; and Vi/2g is the dynamic (or velocity) head.  The summation of the static head and the elevation head, pi/? + zi, is referred to as the piezo metric head.  The piezo metric head is what is measured with the piezometer (manometer) board on the apparatus for this experiment.• Head loss, HL, includes the sum of pipe friction losses, hf, and all minor losses, •     …………• Where hi is the minor head loss (in meters) for the ith component and n is the number of components (fittings, bends, etc.).  Pipe friction losses are expressed as the Darcy-Weisbach equa       ………………………………. (2)• where f is a friction factor, L is the pipe length, and D is the pipe diameter.  Pipe friction losses are assumed to be negligible in this experiment.• Minor losses occur at any bend, transition, or fitting where the streamlines are not straight and are proportional to the velocity head.  For all components, head loss is given•        ………………. (5)• where Ki is the loss coefficient (dimensionless) for the ith component and V is the fluid velocity as it travels through the pipe component.  For the expansion and contraction, the V used in Equation (5) is the velocity of the fluid in the smaller-diameter pipe.  • In this experiment, the loss coefficients for different pipe components will be experimentally determined by calculating the minor head loss using Equation (1) and utilizing Equation (5) to find the loss coefficient.  In Exercise B a pressure difference across a gate valve is measured from a pressure gauge in units of bars and must be converted to an equivalent head loss using the following relationship.                                                                                                                                                                               1 bar = 10.2 m water. • 1 bar = 10.2 m water.           (6)3.5 EQUIPMENT • Arm field Hydraulics Bench with Energy Losses apparatus• Stop Watch• The Energy Losses apparatus is a pipe with several pipe fittings.  Piezometers (a type of manometer) are connected to the pipe upstream and downstream of each fitting to measure the pressure in the pipe at those locations.• Technical Data• The following dimensions from the equipment are used in the appropriate calculations.• Internal diameter of main pipe:0.0196 m• Internal diameter of enlargement outlet and contraction inlet:0.0240