Observation and analysis of results The experiment that has been conducted made use of the venturi and orifice meters in determining the head loss and coefficient coefficie nt of discharge for each flowmeters. From the experiment, we successfully obtained the head loss and coefficient of discharge with comparison of pressure drop. Determined Determined values for the coefficient of discharge for the venturi meter and orifice meter did not achieved the desired values on contrary with the standard values. Error can be accounted with the accuracy of the apparatus, leaks and occasional wearing may affect the data determined. The sudden change in the flow area in the orifice meters causes considerable swirl and as the velocity of the flow increases, the vena contracta decreases.The smaller the vena contracta gets the greater the pressure difference, difference, and thus the higher the energy loss and thus significant head loss. In general, orifice meter have the highest minor loss coefficient, while venturi meter have the lowest. In principle states that in a moving fluid, when the area decrease the velocity is increase and the pressure inside the fluid decrease. According to the laws governing fluid dynamics, a fluid’s velocity must increase as it passes through constriction to satisfy the principle of continuity, while its pressure must decrease to satisfy the principle of mechanical energy. In conclusion, the flow rate in venturi meter is higher than orifice meter.
Conclusion In this experiment, we use the differential flow meters that are the orifice meter and venturi meter. This measuring technique operation and characteristics characteristics was used and by comparing pressure drop that will be calculated that related to the velocity of the fluid in the pipe and calculating the coefficient of discharge. From the data obtained, for the orifice meter high pressure drop is unrecovered this is due to the flow rate is increased at the opening of the orifice plate and not much energy is lost but as it flows through and starts slowing down, much of the excess energy is lost. For the venturi meter, the value obtained were closer to the actual this is due to lower pressure drop that results from its streamlined streamlined shape and almost eliminates eliminates boundary-layer separation and thus form drag is assumed negligible. It has a converging and a diverging part, Although, there may be some pressure loss in the converging part of the venturi meter but in a properly designed venturi meter some percentage of pressure loss is attained back in the diverging part of the meter. This meter is good for high pressure and energy recovery. To be concluded, venture meter was more accurate compared to orifice meter and rotameter.
RECOMMENDATION In this experiment, there are few recommendations that can be applied to get better data and results, thus the experiment can be run properly and systematically. In order to get the accurate data, the experiment must be repeated at least two times and determined the average. Besides, we have to ensure that there is no air bubbles for better accuracy and to avoid readings error. We can used a pen or screw driver to depress the staddle valve at the top right side of manometer board. Depress staddle valve lightly to allow fluid and trapped air to escape out. Allow sufficient time for bleeding to allowing all bubbles escape We also have to monitor the water level in the manometer board. If the water level in the manometer board is too high where it is out of visible point, we need to adjust the water level by using the staddle valve. With the maximum measureable flow rate, retain the maximum readings on manometer.
