Experiment title
Graph for Initial Flow rate Q Vs Coefficient of Discharge Cd
Download 0.82 Mb. View original pdf
|
ASSignment
| Graph for Initial Flow rate Q Vs Coefficient of Discharge Cd As the graph in Fig 1.11 shows that with the gradual increase of the flow rate the Cd value is approximately approaching 1. The coefficient of discharge for Venturimeter is the measure of the efficiency for venturimeter. This in terms means that the value of Cd approaches nearly 1 when the flow rate increases so that the energy loses, friction loses, pressure loses and turbulence loses are less as 10% in venturimeter flow. The straight line indicates that as the flow rate increases the efficiency of venture meter increases. But the value of Cd can never be more then 1 because that means that the experiment will end up with more energy than it had before. Plus Cd can never approach 1 which in return means that the experiment carried was an ideal state with no losses at all. Fig 1.11: Graph on Flow rate Q Vs Coefficient of discharge Cd. 18 As evident from the graph 1.10 the relation between Qa and Qt is a straight line indicating very less pressure, energy, turbulence and friction losses. Further on this means that the value of Cd approximately approaches 1 which in this experimental case is denoted to bean average of 0.97 with only 10% of all energy losses. Cd value can never reach 1 as this might indicate an ideal condition where there are no losses at all. Plus Cd value can never exceed 1 as this may result in excess of energy after the experiment as compare to the beginning of the experiment. As from the fig 1.11 we saw the result that as the initial flow rate increases the value of Cd increases which shows that that value of Cd is more accurate with higher flow rates. In high flow rates the flow of liquid becomes uniform and less turbulent with no eddies formation and reduce energy losses thus the value of Cd is high at higher flow rates as compare to lower flow rates. Actual flow rate Qa is different the then the theoretical flow rate Qt, as Qa can be measure through different methods and by dividing the volume of the fluid by the time taken. Whereas, Qt is measured through a formula which includes a manometric reading with the difference in heights of the liquid. Qt will have higher flow rate as compare to Qa due to friction losses in actual flow processes. The average value of Cd obtained from this experiment is 0.97 which shows that there were certain losses during the experiment was conducted. Other errors could be human measuring time for the collection of L of water. In addition the values in the manometer and the flow meter was fluctuating due to which there could bean error in the measurements. The detailed calculations and excel sheets with graph calculations are attached in the appendix of the report as document 1, 2 and 3. |