Navegando por Autor "MESQUITA, André Luiz Amarante"

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Acesso aberto (Open Access)
An analysis of total phosphorus dispersion in lake used as a municipal water supply
(Academia Brasileira de Ciências, 2015-09) LIMA, Romulo Correa; MESQUITA, André Luiz Amarante; BLANCO, Claudio José Cavalcante; SANTOS, Maria de Lourdes Souza; SECRETAN, Yves
In Belém city is located the potable water supply system of its metropolitan area, which includes, in addition to this city, four more municipalities. In this water supply complex is the Água Preta lake, which serves as a reservoir for the water pumped from the Guamá river. Due to the great importance of this lake for this system, several works have been devoted to its study, from the monitoring of the quality of its waters to its hydrodynamic modeling. This paper presents the results obtained by computer simulation of the phosphorus dispersion within this reservoir by the numerical solution of two-dimensional equation of advection-diffusion-reaction by the method θ/SUPG. Comparing these results with data concentration of total phosphorus collected from November 2008 to October 2009 and from satellite photos show that the biggest polluters of the water of this lake are the domestic sewage dumps from the population living in its vicinity. The results obtained indicate the need for more information for more precise quantitative analysis. However, they show that the phosphorus brought by the Guamá river water is consumed in an area adjacent to the canal that carries this water into the lake. Phosphorus deposits in the lake bottom should be monitored to verify their behavior, thus preventing the quality of water maintained therein.
Acesso aberto (Open Access)
An Investigation of a Mathematical Model for the Internal Velocity Profile of Conical Diffusers Applied to DAWTs
(Universidade Federal do Pará, 2015-06) BARBOSA, Disterfano Lima Martins; VAZ, Jerson Rogério Pinheiro; FIGUEIREDO, Sávio W.O. ; SILVA, Marcelo de Oliveira e; LINS, Erb Ferreira; MESQUITA, André Luiz Amarante
The Diffuser Augmented Wind Turbines (DAWTs) have been widely studied, since the diffusers improve the power coefficient of the wind turbine, particularly of small systems. The diffuser is a device which has the function of causing an increase on the flow velocity through the wind rotor plane due to pressure drop downstream, therefore resulting in an increase of the rotor power coefficient. This technology aids the turbine to exceed the Betz limit, which states that the maximum kinetic energy extracted from the flow is 59.26%. Thus, the present study proposes a mathematical model describing the behavior of the internal velocity for three conical diffusers, taking into account the characteristics of flow around them. The proposed model is based on the Biot-Savart's Law, in which the vortex filament induces a velocity field at an arbitrary point on the axis of symmetry of the diffusers. The results are compared with experimental data obtained for the three diffusers, and present good agreement.
Acesso aberto (Open Access)
Contribution to the marine propeller hydrodynamic design for small boats in the Amazon region
(Instituto Nacional de Pesquisas da Amazônia, 2016-03) FAVACHO, Breno Inglis; VAZ, Jerson Rogério Pinheiro; MESQUITA, André Luiz Amarante; LOPES, Fábio; MOREIRA, Antonio Luciano Seabra; SOEIRO, Newton Sure; ROCHA, Otávio Fernandes Lima da
In the Amazon, river navigation is very important due to the length of navigable rivers and the lack of alternative road networks. Boats usually operate in unfavorable conditions, since there is no hydrodynamic relation among propellers, geometry, and the dimensions of the boat hull. Currently, there is no methodology for propeller hydrodynamic optimization with low computational cost and easy implementation in the region. The aim of this work was to develop a mathematical approach for marine propeller design applied to boats typically found on Amazon rivers. We developed an optimized formulation for the chord and pitch angle distributions, taking into account the classical model of Glauert. A theoretical analysis for the thrust and torque relationships on an annular control volume was performed. The mathematical model used was based on the Blade Element Momentum Theory (BEMT). We concluded that the new methodology proposed in this work demonstrates a good physical behavior when compared with the theory of Glauert and the experimental data of the Wageningen B3-50 propeller.
Acesso aberto (Open Access)
On the prediction of pickup and saltation velocities in pneumatic conveying
(2014-03) GOMES, Luiz Moreira; MESQUITA, André Luiz Amarante
This paper presents a comparative study of the critical pickup and saltation velocities of particles in horizontal pipelines for pneumatic conveying design. A comparative study is performed using different existing correlations in the literature for the determination of the minimum velocity of transport as a function of the particle and pipe diameter, particle density, solid mass flow rate and particle sphericity. Their limitations and difficulties in predicting those critical velocities are analyzed. For the pickup velocity, an experimental study was also carried out in order to support the analysis. Recommendations are presented on the use of such correlations.
Acesso aberto (Open Access)
Pressure regulation and energy recovery in water distribution networks using pumps as turbines
(Associação Brasileira de Engenharia Sanitária e Ambiental, 2023-03) VIANA, Ingrid Luna Baia; BATISTA, Jamile Caroline Moreira; SÁ, João Henrique Macedo; RAMALHO, Rodolfo Vitorino Correia; LOPES, Raynner Menezes; SOUZA, Davi Edson Sales e; MESQUITA, André Luiz Amarante
Water distribution networks (WDNs) are considered a potential renewable energy source, as they have more than enough pressure energy to deliver water to users. To control excessive pressure, WDNs are commonly divided into district metered areas (DMAs) with pressure reducing valves (PRVs). The energy wasted by PRVs can be recovered using pumps as turbines (PATs). However, selecting the appropriate pump remains a challenge, as it must account for daily pressure and flow variations from consumers (off-design conditions). In this article, a combination of models was validated and applied to select the suitable pump for operating in an actual WDN. The replacement of two PRVs with PATs in a real network, previously divided into two DMAs and operating at constant speed was investigated. Economic and environmental analyses were also conducted. PAT1 was technically superior to PAT2 , as PAT2 exhibited negative outlet pressure, affecting the pressure in DMA2 . Optimal efficiencies are achieved at flow rates corresponding to the pump’s best efficiency point or near it, mimicking pressure control as if they were the valves themselves. The most efficient pump recovered 4,331 kWh/year, equivalent to a reduction of 1,732,400 gCO2/year, serving two households categorized as low income. PATs proved to be a viable alternative, with a payback period of 2.1 years, as it can recover renewable energy. However, for effective pressure control in WDNs, other operational strategies, such as variable speed operation, should be explored.