Headloss Through a Valve

Fluid mechanics science lab fountain motion red Through a Valve April 24, 2012 Abstract This test determined the descent in the midst of the point in timeer acquittance with a ingress valve and the point of orifice of that valve with varying current rates. The objective of this experimentation was to determine the valve issue coefficient, K, for a limited entry valve as a role of both the piping Reynolds Number, and the degree of source. The kinship between the Reynolds Number and the crash chemical element was constant. Regardless of what the Reynolds Number was, the skirmish instrument remained the same.This path that the valve head discharge coefficient, K, further depended on the degree of opening of the provide valve. As the valve is slowly one shoted closed, the study head overtaking repayable to brush along the call, decreases, and the squirt Head Loss, payable to the clank by the admission valve, increases. thither is a positive elon inlet blood between the Reynolds Number and the head red coefficient. The slope of this linear kin showed that as the move rate increases, the upper increases which means the Reynolds Number gets bigger and the head pass coefficient increases.Therefore, the higher the flow and the smaller the degree of opening of the door valve, the greater the head loss becomes through the gate valve. circumvent of contents Abstract i 1Introduction1 1. 1 soil1 1. 2Theory1 1. 3Objective1 2 implement and Supplies1 3Procedures4 4Equations4 5Experimental Results5 6Error Analysis9 7Conclusions9 8Recommendations for make headway Studies10 9References10 APPENDIX skirt of Figures Figure 21 closet derivative Gauge ? p. 2 Figure 22 Weighing store with absorb Valve open. 3 Figure 23 imperativeness differential gear Gauge between Valve Set-up3 submit 51 Constants and given cherish. 5 slacken 52 nibd Data. 5 Table 53 Volumetric Flow, speeding, Reynolds , Head Loss Coefficient. 6 Table 54 a uthorized measures of K, major(ip) Head Loss, tiddler Head Loss. 6 Introduction Background Gate valves be frequently employ when constructing and fitting pipes. They provide the capability to fold off particularized lines so that repairs or renovations can be made without having to turn off the main supply lines. Although these valves are useful, they also disturb the normal flow and cause friction. Theory The head loss coefficient, K, for a gate valve is related to the tike Head Loss, Hlm, where Hlm=V22gK.The total head loss in the pipe is divided into dickens parts the Major Head Loss, Hf, referable to the pipe friction over duration L, and the Minor Head Loss. Using the Bernoullis energy equivalence, the coefficient, K, can be engraft K=2g? PV2? -fLD. Objective The objective of this experiment was to determine the valve loss coefficient, K, for a specific gate valve as a pass of both the pipe Reynolds Number, and the degree of opening. Apparatus and Supplies * 1 Weigh ing tank with darn Valve (0. 5 lb) * 2 Stop Watches (0. 01 sec) * Galvanized push pipe 27 inches (0. 03125 in) long with a diameter of 1. 1 inches (0. 0005 in) * 1 Pressure Differential Gauge (0. 05 psi) * 1 Valve turn up in between the Pressure Differential Gauge on Galvanized Iron thermionic tube Figure 21 Pressure Differential Gauge ? p. Weighing Tank Dump Valve Figure 22 Weighing Tank with Dump Valve open. Figure 23 Pressure Differential Gauge between Valve Set-up Procedures 1. Measure the distance between the upstream and downriver instancy sensation tabs. 2. Turn the handle on the gate valve to determine how many turns hold out between fully-opened and fully-closed. 3. Turn on the nitty-gritty and open the absorb valve in the weighing tank. 4.Turn the gate valve so that it is completely open. 5. evidence the Pressure Difference 6. Close the souse valve in the weighing tank. 7. Start and jibe the stopwatches over a 100 lb difference and record the times. 8. Open t he dump valve in the weighing tank and have body of water to drain into the sump. 9. Change the flow of water. Do not change the gate valve. 10. reprise steps 5-8. 11. Turn the gate valve to 75% open. 12. Change the flow of water. 13. fictionalise steps 5-9 a total of terce (3) times. 14. Turn the gate valve to 50% open. 15. Repeat steps 12 and 13. 16. Turn the gate valve to 25% open. 17. Repeat steps 13 and 13.Equations Head Loss Coefficient K=2g? pV2? -fLD Major Head Loss hf=fLDV22g Minor Head Loss hlm=KV22g Reynolds Number Re=VD? Area of Pipe2 A=? 4D2 Velocity V=QA1 Volumetric Discharge Q=? W? t*? Experimental Results Table 51 Constants and given value. Table 52 heedful Data. The friction factor f=0. 049 was measured based on Ks/D and the Reynolds Number. Table 53 Volumetric Flow, Velocity, Reynolds , Head Loss Coefficient. Table 54 Real values of K, Major Head Loss, Minor Head Loss. Error Analysis There were almost values calculated for the valve loss coefficient, K, whi ch were negative.This is unrealistic because a negative K value would give you an overall gain in energy as water flows through the valve according to Bernoullis energy equation. fit in to the equation used, gravity and the specific weight of water are constant. The length and diameter of the pipe along with the velocity had relative errors overdue to human accuracy, but all of these were negligible. This leaves the friction factor, f, and the pressure differential readings. The calculated value of the friction factor was given and was belike over estimated and the absolute hardness of the pipe was less.The accuracy of the pressure differential label was also a possible line of descent of error. Looking at the data, the first cinque readings all had negative K values and they all had very low pressure differential readings. The accuracy of the readings become much inaccurate the closer the readings are to the endings of the scale. Conclusions According to the Moody Diagram and the absolute roughness stated, the relationship between the Reynolds Number and the friction factor was constant. Regardless of what the Reynolds Number was, the friction factor remained the same.This means that the valve head loss coefficient, K, was only depended on the degree of opening of the gate valve. As the valve is slowly morose closed, the Major Head Loss due to friction along the pipe, decreases, and the Minor Head Loss, due to the friction through the gate valve, increases. There is a positive linear relationship between the Reynolds Number and the head loss coefficient. The slope of this linear relationship showed that as the flow rate increases, the velocity increases which means the Reynolds Number gets bigger and the head loss coefficient increases.Therefore, the higher the flow and the smaller the degree of opening of the gate valve, the greater the head loss becomes through the gate valve. Recommendations for Further Studies The experiment could set nominal and maximum standards for readings off the pressure differential gauge. For each valve reading, making the minimum pressure difference greater than 1. 0 psi and less than 9 PSI would moderate that there are no endpoint inaccuracies. References Giles, Ranald V. , Jack B. Evett, and Cheng Liu. Schaums Outline of Fluid Mechanics and Hydraulics. New York McGraw-Hill, 2009. Print. Appendix