This article discusses the development and the establishment of turbulent flow downstream of disturbers like a valve 50% open, valve 70% open, Tee and 90° double bend in perpendicular planes. Associated with these disturbers, a perforated plate flow conditioner is installed to examine his performances to produce the fully developed pipe flow as suggested by standards ISO5167 and AGA3. The study focused mainly on the numerical analysis of the velocity contours at several axial stations downstream the disturbers. For the simulation, code CFD Fluent was used. The study of the disturbed flow is examined with three Reynolds numbers. The results show a very good prediction of the CFD code Fluent for the flow development downstream the disturbers and conditioner which makes the code very efficient for conception of a new flow conditioner not described by the standards. It was also found that the valve 50% open could be considered a reference disturber for analyzing the development of turbulent flows. As interesting results, is the effectiveness of the perforated plate to produce the flow developed pipe flow at about z/D=10 downstream the disturber. This result is very important for flow measurement accuracy as suggested by the standards. An experimental study is needed to validate these results.

Abstract. This paper present a part 1 of numerical experimentation of the behaviour of the discharge coefficient and the effect of four perforated plates flow conditioners on the discharge coefficient for flow measurement accuracy. Three of the plates are described by the Standard ISO5167 and the fourth one is proposed for study. In this part 1, the disturber used is 90q double bend in perpendicular planes while in the part 2 the flow is subject to disturbers namely 30% and 50% closed valves. The turbulent flow is examined in conduit with an inner diameter of D=100mm. The diameter of orifice meters are respectively d=50, 60, 70 and 75mm which done for E=d/D respectively the values of 0.5, 0.6, 0.7 and 0.75. The orifice meters are located in conduit at different stations z/D downstream the disturber. The flow is examined with air at Reynolds number Re=2.5x10 5 . The software used for this simulation is ANSYS package with k-H like turbulence model. A numerical investigation was done before (CIM 2013) with the same conditions but without perforated plates and the results showed that when the diameter of the orifice meter increases the shifts deviation of the discharge coefficient increases this causes a great error in flow measurement. Contrary, when the diameter of the orifice meter decreases the shifts deviation in the discharge coefficient decreases and the error in flow measurement is reduced. These results are the same with the two disturbers 90q double bend and 50% closed valve used separately in conduit. In this paper the results showed that the perforated plates have significantly reduced the error on the discharge coefficient. Indeed, the errors recorded downstream disturbers are superior to 2%. Downstream the perforated plates used separately the errors on the discharge coefficient are reduced to a value inferior to 1% for the four plates. It is noted that the standards ISO5167 and AGA3 stipulate that the error on the discharge coefficient Cd must be less than ±0.5% for better flow measurement accuracy. By comparing our results with this condition we found that the results obtained with the four plates are substantially reduced especially downstream station z=25D (z=20.5D downstream flow conditioners). However the fourth proposed plate with its high porosity produces less losses pressures than those of the other three plates. This is good condition of exploitation for some installation where high losses pressures are not tolerated.

Abstract. This paper present a part 1 of numerical experimentation of the behaviour of the discharge coefficient and the effect of four perforated plates flow conditioners on the discharge coefficient for flow measurement accuracy. Three of the plates are described by the Standard ISO5167 and the fourth one is proposed for study. In this part 1, the disturber used is 90q double bend in perpendicular planes while in the part 2 the flow is subject to disturbers namely 30% and 50% closed valves. The turbulent flow is examined in conduit with an inner diameter of D=100mm. The diameter of orifice meters are respectively d=50, 60, 70 and 75mm which done for E=d/D respectively the values of 0.5, 0.6, 0.7 and 0.75. The orifice meters are located in conduit at different stations z/D downstream the disturber. The flow is examined with air at Reynolds number Re=2.5x10 5 . The software used for this simulation is ANSYS package with k-H like turbulence model. A numerical investigation was done before (CIM 2013) with the same conditions but without perforated plates and the results showed that when the diameter of the orifice meter increases the shifts deviation of the discharge coefficient increases this causes a great error in flow measurement. Contrary, when the diameter of the orifice meter decreases the shifts deviation in the discharge coefficient decreases and the error in flow measurement is reduced. These results are the same with the two disturbers 90q double bend and 50% closed valve used separately in conduit. In this paper the results showed that the perforated plates have significantly reduced the error on the discharge coefficient. Indeed, the errors recorded downstream disturbers are superior to 2%. Downstream the perforated plates used separately the errors on the discharge coefficient are reduced to a value inferior to 1% for the four plates. It is noted that the standards ISO5167 and AGA3 stipulate that the error on the discharge coefficient Cd must be less than ±0.5% for better flow measurement accuracy. By comparing our results with this condition we found that the results obtained with the four plates are substantially reduced especially downstream station z=25D (z=20.5D downstream flow conditioners). However the fourth proposed plate with its high porosity produces less losses pressures than those of the other three plates. This is good condition of exploitation for some installation where high losses pressures are not tolerated.