Apparati and benches

Place the apparatus on the hydraulics bench, and ensure that the outflow tube is positioned above the volumetric tank to facilitate timed volume collections.• Level the apparatus base by adjusting its feet. (A sprit level is attached to the base for this purpose.) For accurate height measurement from the manometers, the apparatus must be horizontal.• Install the test section with the 14° tapered section converging in the flow direction. If the test section needs to be reversed, the total head probe must be retracted before releasing the mounting couplings.• Connect the apparatus inlet to the bench flow supply, close the bench valve and the apparatus flow control valve, and start the pump. Gradually open the bench valve to fill the test section with water.• The following steps should be taken to purge air from the pressure tapping points and manometers:o Close both the bench valve and the apparatus flow control valve.o Remove the cap from the air valve, connect a small tube from the air valve to the volumetric tank, and open the air bleed screw.o Open the bench valve and allow flow through the manometers to purge all air from them, then tighten the air bleed screw and partly open the bench valve and the apparatus flow control valve.o Open the air bleed screw slightly to allow air to enter the top of the manometers (you may need to adjust both valves to achieve this), and re-tighten the screw when the manometer levels reach a convenient height. The maximum flow will be determined by having a maximum (h1) and minimum (h5) manometer readings on the baseboard.If needed, the manometer levels can be adjusted by using an air pump to pressurize them. This can be accomplished by attaching the hand pump tube to the air bleed valve, opening the screw, and pumping air into the manometers. Close the screw, after pumping, to retain the pressure in the system.• Take readings of manometers h1 to h6 when the water level in the manometers is steady. The total pressure probe should be retracted from the test section during this reading.• Measure the total head by traversing the total pressure probe along the test section from h1 to h6.• Measure the flow rate by a timed volume collection. To do that, close the ball valve and use a stopwatch to measure the time it takes to accumulate a known volume of fluid in the tank, which is read from the sight glass. You should collect fluid for at least one minute to minimize timing errors. You may repeat the flow measurement twice to check for repeatability. Be sure that the total pressure probe is retracted from the test section during this measurement.• Reduce the flow rate to give the head difference of about 50 mm between manometers 1 and 5 (h1-h5). This is the minimum flow experiment. Measure the pressure head, total head, and flow.• Repeat the process for one more flow rate, with the (h1-h5) difference approximately halfway between those obtained for the minimum and maximum flows. This is the average flow experiment.• Reverse the test section (with the 21° tapered section converging in the flow direction) in order to observe the effects of a more rapidly converging section. Ensure that the total pressure probe is fully withdrawn from the test section, but not pulled out of its guide in the downstream coupling.