Flow Through A Venturi Meter

fertilise Through A Venturi MeterGiven a Venturi Meter, Cv , the Venturi coefficient buns be determined to comp ar the actual and sublime determine as per Bernoullis predictions, for a volume flow rate. For better comparisons, two go bad trials were analyzed and Venturi coefficients for both were computed. Trial 1 and Trial 2 yielded a Cv of 0.93 and 0.92 respectively. In this investigate the value metrical were found to be less than 1.0 this relation backly high correlation between the experimental and ideal flows for the given Venturi meter however when compared to the ideal flow, the actual flow for this Venturi is not steady nor superstar dimensional. and so neither of these assumptions can be employ to any given actual flow.NomenclatureVariable/ Constant/ emblem/ParameterValuesQVolume flow rate (m3/s)V pep pill (m/s)AArea (m2)air parsimoniousness of air, 1.23 kg/m3waterDensity of water, 1000 kg/m3CvVenturi coefficientPoStagnation military press (Pa) is smooth Pres sure plus alive(p) PressurePatmAtmospheric pressure, 101.325 KPah summit difference (m) between readings and PatmgAcceleration, 9.81 m/s2zElevation of arrest (m)()V2Dynamic Pressure (Pa)P unchanging PressureFlow depth psychologyBernoullis Equation relates two charge ups alongside a streamline asP1 + ()airV12+ airgz1 = P2 + ()airV22 + airgz2z is negligible so airgz cancels come in on both sides leavingP1 + ()airV12+ = P2 + ()V22RearrangingP1 P2 = ()air(V22 V12) differentiation thatQideal = V1A1 = V2A2.Solving for V2V2 =Subbing (5) into (3) and solving for V1V1 =ThenQideal = A1Flow Analysis (Contd)For the parentage of Qactual, sufficient distance from the Venturi inlet is assumed for a fluid particles relative velocity to be interpreted as zero. The same height (z value) as the Venturi will be taken for the particle.P1 + ()airV12+ airgz1 = P2 + ()airV22 + airgz2z is negligible so airgz cancels out on both sides leavingP1 + ()airV12+ = P2 + ()V22as stated, the fluid particles ve locity at point 0 is assumed to be 0m/sPatm = P2 + ()airV22Solving for V2V2 =P2 is outlined as the static pressure at the inlet, found to beP2 = Patm + waterghSubbing (9) into (8)V2 =To find QactualQactual = V2A2.Sub (11) into (12) where A2 is the cross sectional areaQactual = A2Flow Analysis (Contd)With set for Qactual and Qideal, Cv can then be metrical with the relationCv =For ideal static pressures combine (8) having solved for P2 and (4) having solved for V2P2 = Patm ()airV22P2 = Patm ()airExperimental Setup and ProcedureThe experiment was carried out per the instruction manual outlined in the course manual. However due to a business with the apparatus and a constantly fluctuating Venturi meter, a camera was utilise to take a photo. Measurements were taken from the scale viewed on s economic aid picture. find Shows Experimental SetupResultsFor trial 1Qideal = 0.01238 Qactual = 0.01153The Venturi Coefficient, Cv, was calculated by utilise the values found for Qideal and Qactual and substituting them into equation (14). This value obtained was 0.93.To find the stagnation pressure, P = Patm and V = 0 the total pressure at this point is equal by P0 = Patm + ()airV2, however since V = 0 , the stagnation pressure is P0 = Patm.The Static Pressure is Patm = Patm watergh where the h used is the value that corresponds with the throat. and then Pthroat = 99.206KPaFor Dynamic Pressure, ()airVthroat2 = Patm Pthroat = 2.119KPaResults(Contd)For trial 2Qideal = 0.01238 Qactual = 0.01153The Venturi Coefficient, Cv, was calculated by using the values found for Qideal and Qactual and substituting them into equation (14). This value obtained was 0.92.To find the stagnation pressure, P = Patm and V = 0 the total pressure at this point is represented by P0 = Patm + ()airV2, however since V = 0 , the stagnation pressure is P0 = Patm.The Static Pressure is Patm = Patm watergh where the h used is the value that corresponds with the throat. Therefore Pthroat = 96.871 KPaFor Dynamic Pressure, ()airVthroat2 = Patm Pthroat = 4.454KPaDiscussionThe two calculated Venturi Coefficients for both trials of differing flow rates were found to contain close enough values to assume that said coefficients do not depend on the flow rate but sort of on the Venturi meter in use. For ideal calibration methods, an average of values, 0.92 and 0.93 could be taken to compensate for ideal assumptions which have been determined to be inaccurate. This would aid the user to find actual values once ideal ones have been found.Although these values are not 1.0, they are comparatively close. However condescension this, it can be inferred that the idealistic conditions assumed at the beginning of the experiment are invalid as they do in fact prevail a noticeable effect on the results creating an error. These assumptions included a one dimensional steady flow that existed in a abrasionless environment such implies no energy transfers.Dimensions for the outlet and inlet were assumed to be equal however if the graphs are reviewed, there are discrepancies and a reliable amount of irregularities. These further outline the existence of friction and energy discharge which can be observed through the comparison of tables 1 and 2 in the vermiform process where the values of experimental and ideal static pressures are defined.There was however another source of error that was introduced due to the wrong(p) apparatus as was discussed in the Experimental Setup and Procedure section. Measurements were taken from a photograph to facilitate taking down said measurements from a fluctuating Venturi meter.Bernoullis equation states that when a fluid in flow undergoes a rise in pressure, then its velocity must decrease. Said creation also applies the other way around. Figure 1 in the appendix illustrates this through a rough sketch.ConclusionVenturi coefficients such as the ones calculated in this experiment, 0.92 and 0.93 imply that the actual flow is lower t han the ideal flow. Therefore the ideal conditions that were applied only give an approximation to the actual flows. The coefficients can be averaged for a more accurate way to calibrate the Venturi meter. The values found imply that the Venturi meter relates the actual and ideal values relatively well however this may be due to the fluctuating meters. as well as very likely, is the presence of a relatively low amount of friction and symmetrical dimensions in the Venturi meter.ReferencesUniversity, Carleton, ed. MAAE 2300 Course Manual. Ottawa, 2011. Print.