Flow in Pipe Circuits Minor Losses Egr 365 Experiment 7b Performed by Lee C Groeneweg Professor Dr Fleischmann Outline I Purpose to experimentally determine minor losses for water flow through various fittings and to compare them to values previously published data II Procedure A Derivations of necessary equations B Measure time t for water to drain a distance h C Find minor loss coefficients using equation k A0 At 2gt2 h0 h 2 A0 At 2 1 0 III Results A Pipe nipple with no fittings B Pipe nipple with globe valve fitting IV Conclusions A Comparison with Published values obtained from handout of fittings B Discuss any discrepancies Purpose To experimentally determine minor losses for water flow through various fittings and to compare them to values previously published data V Procedure For this lab fittings were attached to a metal nipple pipe to determine the minor loss coefficients k This was done by measuring the height as a function of time as the tank drained As the tank drained the time it took to drain to a specified height was recorded This value was then used in the following equation as the h t value This equation is used to determine the summation of the minor losses k A0 At 2gt2 h0 h 2 A0 At 2 1 0 where A0 is the area of the fitting At is the area of the tank and h0 is the original water depth and h is the water depth at time t Figure 1 shows how the apparatus used is designed Figure 1 Tank apparatus used for experiment VI Results By substituting in the values for h and t the k values for the fittings could be determined This equation was derived from the conservation of mass and energy equations with the derivations attached as Appendix A Table 1 shows the values for k with no fittings No Fitting height in height ft time k value 10 0 833333 0 Fitting Diameter 12 1 3 77 0 54886 0 041666667 14 1 166667 7 52 0 51288 Fitting Area 16 1 333333 11 15 0 48775 0 00211 18 1 5 15 08 0 43663 Tank Diameter 20 1 666667 19 18 0 38002 0 833333333 22 1 833333 23 55 0 31327 Tank Area 24 2 27 87 0 25535 0 545415391 26 2 166667 32 49 0 18627 gravity 28 2 333333 37 02 0 12591 32 2 30 2 5 32 2 666667 34 2 833333 Table 1 k values for pipe with no fittings 42 02 46 99 52 55 0 04731 0 025984 0 121185 Table 2 shows the values for k with a inch nom globe valve W Fitting height height ft time k value 10 0 833333 0 00 Fitting Diameter 12 1 10 46 2 472763 0 041666667 14 1 166667 20 71 2 694474 Fitting Area 16 1 333333 31 31 3 039618 0 00211 18 1 5 42 40 3 453598 Tank Diameter 20 1 666667 53 93 3 90152 0 833333333 22 1 833333 65 40 4 29601 Tank Area 24 2 77 52 4 760967 0 545415391 26 2 166667 89 96 5 238407 gravity 28 2 333333 102 71 5 728226 32 2 30 2 5 116 40 6 310409 32 2 666667 129 93 6 844103 34 2 833333 144 96 7 531458 Table 2 k values for pipe with globe valve fitting VII VIII IX Conclusions From the tables it is shown that the minor losses increase as the water depth decreases going down in the tank This would suggest that the friction factors of the fittings have a greater effect when the flow speed is decreased It is worth noting that the vales for k in the no fittings experiment is peculiar since most of the values are negative Also the values for k for the globe valve include the k values for the nipple pipe When compare to published values the pipe itself which represents only a round edged entrance is close to the published value of 0 2 0 25 The values for the globe valve however are not nearly as close to the published value of 14