Cyclones are one of the most used equipment for gas cleaning. These devices are widely used because of their simple construction, low energy requirements and their ability to work with high temperature and pressure levels. In this work, a flow visualization of a cyclone separation system is carried out. For that purpose, smoke particles and a laser beam were used to show the flow patterns within the separation system. The objective of this work is to visualize the flow within a cyclone separation system to elucidate the effect of the flow patterns in the gas-particle separation and the optimization of the cyclone.
The comparison of experimental data and results obtained from four global models — homogeneous, Dukler, Martinelli and Chisholm, used to evaluate the two-phase flow pressure drop in circular 90° horizontal elbows — is presented in this paper. An experimental investigation was carried out using three galvanized steel 90° horizontal elbows (E1, E2, E3) with internal diameters of 26.5, 41.2 and 52.5 mm, and curvature radii of 194.0, 264.0 and 326.6 mm, respectively. According to the experimental results, the model proposed by Chisholm best fitted them, presenting for each elbow an average error of E1 = 18.27%, E2 = 28.40% and E3 = 42.10%. Based on experimental results two correlations were developed. The first one is the classical Chisholm model modified to obtain better results in a wider range of conditions; it was adjusted by a dimensionless relationship which is a function of the homogeneous volumetric fraction and the Dean number. As a result, the predictions using modified Chisholm model were improved presenting an average error of 8.66%. The second developed correlation is based on the entire two-phase mass flow taken as liquid and adjusted by the homogeneous volumetric fraction ratio. The results show that this last correlation is easier and accurate than the adjusted Chisholm model, presenting an average error of 7.75%. Therefore, this correlation is recommended for two-phase pressure drop evaluation in horizontal elbows.
En este trabajo se presenta un prototipo virtual para la detección de fugas de agua potable en un sistema de tuberías desarrollado en MATLAB y Simscape. Se parametrizaron los equipos con características proporcionadas por los fabricantes para tener un comportamiento apegado a un sistema real. El sistema se integró de un tanque de almacenamiento, una bomba centrífuga para recircular el agua, transmisores de flujo y presión, así como seis válvulas de control para simular fugas en diferentes ubicaciones en la tubería. En el prototipo se implementó un algoritmo de detección de fugas basado en observadores de alta ganancia, lo que permitió detectar las fugas en tres escenarios propuestos.
This paper shows a proposal for a control scheme for the trajectory tracking problem in a Two Degree of Freedom Helicopter (2DOFH). For this purpose, a control scheme based on a feedback linearization combined with a Generalized Proportional Integral (GPI) controller is used. In order to implement linearization by feedback, it is required to know and have access to all the physical 2DOFH parameters, however, angular velocity and viscous friction are often not available. Commonly, state observers are used to know the angular velocity, however, estimating friction results out to be more complex. Therefore, we propose the use of a Convolutional Neural Network (CNN) to estimate viscous friction and angular velocity. The variables estimated by the CNN are entered into both the GPI and feedforward controllers. Thus, the system is brought to a linear representation that directly relates the GPI control to the dynamics of perturbations and non-model parameters. Finally, results of numerical simulations are shown that validate the robustness of our scheme in the presence of disturbances in the tail rotor, as well as the advantages of using a feedforward control based on a CNN. INDEX TERMSFriction estimation, Neural networks, Non-linear system, Tail rotor disturbance, Two degrees of freedom helicopter. Hence, different experimental prototypes have been developed to study helicopter dynamics [13]-[15]. One of the most popular consists of a Two Degree of Freedom Helicopter (2DOFH), which recreates the dynamic behavior of the helicopter in its pitch (θ) and yaw (ψ) rotations [15], [16].
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