Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
EXPERIMENTAL TEST OF CRITICAL REYNOLDS NUMBER CORRELATION IN BIFURCATIONS
Submission Author:
Flavio Peres Amado , RJ , Brazil
Co-Authors:
Arthur Moreira Estevão de Moraes , Jhonata Lopes, Louise Pedro de Paula, Patricia Saldanha, Flavio Peres Amado
Presenter: Flavio Peres Amado
doi://10.26678/ABCM.COBEM2021.COB2021-0277
Abstract
In this work, it is proposed to experimentally confirm a forecast correlation of critical Reynolds Number, Recrit, in bifurcations with varied asymmetric angles, raised and published in a recent article by the author. It is well known that a disturbance in a straight section of piping, where there is a flow in laminar regime, such as a curve, a valve or a bifurcation, will cause turbulence in the stream. But after the obstacle, it returns to the laminar state. However, there is a Reynolds Number value that indicates that the flow will not return to the initial condition and the correlations that indicate such a quantity are known for a large number of geometries. For experimental verification and validation of the correlation for bifurcations, a hydraulic apparatus was designed, composed of an acrylic container, with support for asymmetric glass forks with a tube diameter equal to 0.016 m (or 5/8”) and several angles. A pump with a maximum flow rate of 5.8x10-5 m3/s (or 3.5 l/min, according to the manufacturer's original specification), being controlled by a potentiometer and a rotameter that indicates the imposed flow rate, makes the fluid (water) circulate from the filled container into the fork. When making the water pass through this circuit, an injector drives a colored thread, whose behavior is observed along the flow inside the outlets. The apparatus was installed and operated in the university's hydraulics laboratory. Basically, the resource allows the researcher to observe the trajectory of the fillet through the bifurcated channels. When the flow changes from laminar to turbulent regime and does not return to the initial condition, the flow rate is recorded. The velocity value and the consequent Reynolds Number can thus be calculated and compared to that predicted by the proposed correlation. Most of prediction work has been based on computer simulation only and this experimental evidence makes previous conclusions more reliable. Preliminary results indicate very low values of Recrit. New bifurcations are being manufactured to carry out complementary tests, aiming to complete the analysis of the adequacy of the correlations and the maturity of the conclusions.
Keywords
Bifurcations, Critical Reynolds Number, experimental validation
DOWNLOAD PDF VIEW PRESENTATION
