Aplicación de la técnica del hilo caliente volador en la detección y medición del flujo axial inverso

The existence of reversal axial flow induced in the center of a swirling flow through ducts of circular cross section is determined. Some contradictory statements found in the literature related with the detection and measurement of such reversal axial flow are analyzed and the feasibility of measuring it using the flying hot wire technique is studied. With this technique, the reversal axial flow was detected up to a radial position of 3 cm. However, such flow was intermittent and its axial position was not the same in each radial position. Therefore, it is not possible to make a radial distribution of the axial velocity using one sensor only. Finally, it is concluded that the intermittent reversal axial flow is similar to the recirculation flow that is generated in the wake of a body in movement.