/n/n Hose Friction Factor and Valve Loss Coefficient This handout must be completed and shown to your TA by the end of the laboratory class period. Laboratory objectives: This laboratory has two objectives: (1) Quantify the friction factor and its Reynolds number dependence for a 3/8" hose, and determine the effective roughness (e) of the hose. (2) Quantify the loss coefficient of an adjustable valve as a function of its position (fully open -> 360° closed). Methodology: The experimental setup is straightforward: a 50' long, 3/8" diameter hose is attached to the building plumbing system. A pressure gage is located at the upstream attachment point and allows for the estimation of the pressure drop in the hose caused by the hose itself and the valve (if attached). There is a small effect of elevation between the pressure gage and the outlet that should also be accounted for. first purt no minor luss Sketch Second Ο Port Umbur las 21+ 425 = 8 = 1+12 t V₁ = V2 +212 +2 + hm 2g h2+ hm 8 r ง PL PE (-A) سال hm = k < K= 21+ ditum To conduct an experiment, a flow is set through the hose using the valve at the wall. This flow rate is measured using a simple volume vs. time measurement and some containers of known volumes, and the pressure drop is measured using the upstream pressure gage. There are two sets of experiments: (1) Experiments with hose only (done as a class): If there is no valve on the end of the hose, then the measured pressure drop is caused by the elevation drop and the hose friction alone. This set of experiments is the same as was done last week, except that we are attempting to do them over a larger range of flow rates (Reynolds numbers). These experiments allow you to isolate the friction factor as the only unknown in the pipe flow energy equation: 25 Sample calculation for f from one of the in-class experiments (complete for credit): AL ESC (2) Experiments with hose and valve (done in small groups): The second set of experiments has you doing similar measurements as above, except that an adjustable valve is placed at the end of hose. Technically now there are two unknowns in your pipe flow energy equation (hose friction factor, f, and the valve loss coefficient, K), but you will rely on your estimations of f in the first set of experiments to isolate the valve loss coefficient in your pipe flow energy equation: Sample calculation from the with-valve experiment done as a class (complete for credit): Additional information and considerations: · Make sure that the hose is not excessively coiled or kinked, as this can increase losses. • • Note the resolution of each measurement type so that you can determine the uncertainty of your estimated friction factors and valve coefficients. For example, how accurate can you read the pressure gage? How accurate do you know the elevation drop? One of these uncertainties will likely drive the uncertainty in your estimated friction factors and loss coefficients. This lab exercise will be used as the basis for one of the two formal reports for CE343 this semester. As such, you are encouraged to take good notes, photos, etc. in order to have all the information that you will need to accomplish the stated objectives and communicate these results in sufficient detail. Sample data sheets are given here to guide your notes and calculations, but take the initiative to modify them and take additional notes as needed. As usual, you are encouraged to work with your classmates and groupmates, but ultimately you will need to write your own report. V= A ✓ FA m² 6-VA First set of experiments: hose only Hose length: Hose diameter: 318 "= 0.03125 ft A: 7.67x10-4 fr So ft Hose cross-section area: 7.67x ft² 110365×10-5 Re: VD ? Temperature: 71 °F Water viscosity (v): Experiment Measured (done as class) pressure Measured pressure (psig) (psfg) Gage elevation above Volume Time of Flowrate Average collected collection (cfs) velocity ft2/s Velocity head (ft) Reynolds number Estimated friction factor (units vary) (s) (ft/s) outlet (ft) v²/2g 4 576 2.08 1000ML 16.3 0.03216 2.32 0.123 85012.2 0.057 6 864 2.08 1000 12.9 10 2.08 1000 915 IS 2108 970mL 7.98 20 2108 1000ml 6178 25 2.08 930 5.85 30 3.58 ادوا 21.15 95 3.58 lyul 18,92 Su 3.58 ادوا 15.72 (0 3.58 \ yol 15.44 Uncertainties/ resolution Sample calculation for f: f= f = £ 20 (2₁ + (-) - 0.03125 2032.2) = (2₁us + 576 So (2.82)² 62.4 (7 29157 More open less hm Second set of experiments: hose + valve TA Experiment Valve Measured setting pressure (deg. (psig) Measured pressure (psfg) Gage elevation above (units Volume Time of Flowrate Average Velocity Reynolds f Estimated collected collection (cfs) velocity (s) (ft/s) head (ft) number assumed K (from first closed) outlet vary) v²/2g exp'ts) (ft) Done w/class 2815 10 1440 380ml 10.66 0.0134 1.64 0.0413 4944.52 0.057 512.4 27.5 30 73431 11.44 27.5 6. ا دوا 31.83 3 lu 870ml 23.84 us 30 ادوا 4691 95 6. 19.1 25.49 90 10 Igal 48.35 90 30 Igal 25.61 90 60 Igal 16.21 360 lu 2gul 84.27 360 30 2gul 47.10 360 60 Zsul 32134 Uncertainties/ resolution Sample calculation for K (use "done w/class" experiment): 38,17 틈=0.013 K= 2+-hL der 512.4 1½ = -1.8 lun. [(117) + 6)] - t Re 2/ -447 1. SA 4.47 6047=4