flow pressure
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Irriga ◽  
2022 ◽  
Vol 1 (4) ◽  
pp. 739-747
Author(s):  
Madson Rafael Barbalho da Silva ◽  
Lívia Maria Cavalcante Silva ◽  
Ana Cláudia Davino dos Santos ◽  
Fabiano Simplicio Bezerra ◽  
Caio Sérgio Pereira de Araújo ◽  
...  

AVALIAÇÃO DE DESEMPENHO DO MICROASPERSOR EM LINHA LATERAL E SIMULAÇÃO MATEMÁTICA DE SEU GRADIENTE DE ENERGIA     MADSON RAFAEL BARBALHO DA SILVA1; LÍVIA MARIA CAVALCANTE SILVA1; ANA CLÁUDIA DAVINO DOS SANTOS1; FABIANO SIMPLICIO BEZERRA1; CAIO SÉRGIO PEREIRA DE ARAÚJO1 E MANASSÉS MESQUITA DA SILVA1   1 Departamento de Engenharia Agrícola, Universidade Federal Rural de Pernambuco, Dom Manuel de Medeiros, s/n, Dois Irmãos, 52171-900, Recife, Pernambuco, Brasil. E-mail:[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]     1 RESUMO   Objetivou-se avaliar o desempenho do microaspersor Agropolo modelo MC20 em diferentes condições hidráulicas, gerando informações para um melhor dimensionamento de sistemas de microirrigação e manejo da água em áreas irrigadas. A condução do projeto hidráulico para simulação do gradiente de energia em linhas laterais, considerou-se informações determinadas através da escolha de componentes do projeto. Foram extraídos do catálogo comercial do fabricante os pares de valores referentes a vazão e a pressão e, a partir destes, gerou-se a curva vazão-pressão, onde a simulação foi feita pelo Método Algébrico - Christiansen (MA) e Método Iterativo (SBS) – Back-Step. Para ambos métodos o microaspersor se comportou de maneira semelhante, quando submetido a condições sugeridas pelo fabricante, num espaçamento entre emissores de 5,2 m, usando tubos de polietilenos de diâmetro interno de 13 mm e uma pressão de serviço de 20 mca, admitindo uma variação de 10% da pressão. Foram calculados os coeficientes de uniformidade de pressão (CUp) e de vazão (CUq), ambos com valores superiores à 95%, demonstrando a excelência no desempenho do emissor.   Palavras-chave: hidráulica, modelagem matemática, coeficiente de descarga.     SILVA, M. R. B.; SILVA, L. M. C.; SANTOS, A. C. D.; BEZERRA, F. S.; ARAUJO, C. S. P.; SILVA, M. M. PERFORMANCE EVALUATION OF THE SIDE LINE MICROSPARENT AND MATHEMATICAL SIMULATION OF ITS ENERGY GRADIENT     2 ABSTRACT   The objective was to evaluate the performance of the Agropolo model MC20 microsprinkler under different hydraulic conditions, generating information for a better design of micro-irrigation systems and water management in irrigated areas. The conduction of the hydraulic project to simulate the energy gradient in lateral lines, considered information determined through the choice of project components. The pairs of values ​​referring to flow and pressure were extracted from the manufacturer's commercial catalog and, from these, the flow-pressure curve was generated, where the simulation was performed using the Algebraic Method - Christiansen (MA) and Iterative Method (SBS) – Back-Step. For both methods, the microsprinkler behaved similarly, when subjected to conditions suggested by the manufacturer, in a spacing between emitters of 5.2 m, using polyethylene tubes with an internal diameter of 13 mm and a working pressure of 20 mca, admitting a 10% pressure variation. The uniformity of pressure (CUp) and flow (CUq) coefficients were calculated, both with values ​​above 95%, demonstrating the excellence in the performance of the emitter.   Keywords: hydraulic, mathematical modeling, discharge coefficient.


Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 98
Author(s):  
Athanasios V. Serafeim ◽  
George Kokosalakis ◽  
Roberto Deidda ◽  
Irene Karathanasi ◽  
Andreas Langousis

Quantification of water losses (WL) in water distribution networks (WDNs) is a crucial task towards the development of proper strategies to reduce them. Currently, WL estimation methods rely on semi-empirical assumptions and different implementation strategies that increase the uncertainty of the obtained estimates. In this work, we compare the effectiveness and robustness of two widely applied WL estimation approaches found in the international literature: (a) the water balance, or top-down, approach introduced by the International Water Association (IWA), and (b) the bottom-up or minimum night flow (MNF) approach, based on a recently proposed probabilistic MNF estimation method. In doing so, we use users’ consumption and flow-pressure data from the 4 largest pressure management areas (PMAs) of the WDN of the city of Patras (the third largest city in Greece), which consist of more than 200 km of pipeline, cover the entire city center of Patras, and serve approximately 58,000 consumers. The obtained results show that: (a) when MNF estimation is done in a rigorous statistical setting from high resolution flow-pressure timeseries, and (b) there is sufficient understanding of the consumption types and patterns during day and night hours, the two approaches effectively converge, allowing for more reliable estimation of the individual WL components. In addition, when high resolution flow-pressure timeseries are available at the inlets of PMAs, the suggested version of the bottom-up approach with probabilistic estimation of MNF should be preferred as less sensitive, while allowing for confidence interval estimation of the individual components of water losses and development of proper strategies to reduce them.


2022 ◽  
Vol 148 (1) ◽  
Author(s):  
Zhengwen Li ◽  
Zhaowei Liu ◽  
Haoran Wang ◽  
Yongcan Chen ◽  
Ling Li ◽  
...  

2021 ◽  
Vol 9 (12) ◽  
pp. 236-243
Author(s):  
Andrin Kerpaci ◽  
◽  
Ilir Abdullahu ◽  

The condition of the water supply and the actual functioning of the distribution network in Durres area are inadequate to sustain demand at an acceptable level of service for all the billing zones.The distribution network of Durres city is fed at one point (Xhafzotaj junction) for 300-350 l/s with an elevation of about 50 m asl. The planned new transmission line has a diameter of 700 mm and will bring extra 630 l/s.The water distribution systems are one of the vital urban infrastructures and their operationwith a high level of service are of high importance.Many phenomena in water supply systems such as leakage, breakage of pipes etc. are afunction of pressure. When pressure dependency of demand is considered in the hydraulicanalysis, the results thereof shall be consistent with reality.This article presents the new design methodology for a good optimization of the distribution network. The distribution network has been reconstructed as a ring network. It is planned to build 6 DMAas (District Metered Area) to control the flow, pressure and consumption in DMA to build the Water Balance.


Mechanika ◽  
2021 ◽  
Vol 27 (6) ◽  
pp. 498-504
Author(s):  
Wenhua JIA ◽  
Chenbo YIN ◽  
Guo LI ◽  
Dasheng ZHU ◽  
Yanyan LIU ◽  
...  

This work was supported in part by The National Natural Science Fund of China, Scientific research fund of Nanjing Institute of Technology, Open fund project of Anhui University of Technology, Practical innovation project of graduate students in Jiangsu Province. Support Fund Nos. 51505211, 11302097, CKJB201901, HVC202004, SJCX20_0700.


2021 ◽  
Vol 3 ◽  
Author(s):  
Simona Celi ◽  
Emanuele Vignali ◽  
Katia Capellini ◽  
Emanuele Gasparotti

The assessment of cardiovascular hemodynamics with computational techniques is establishing its fundamental contribution within the world of modern clinics. Great research interest was focused on the aortic vessel. The study of aortic flow, pressure, and stresses is at the basis of the understanding of complex pathologies such as aneurysms. Nevertheless, the computational approaches are still affected by sources of errors and uncertainties. These phenomena occur at different levels of the computational analysis, and they also strongly depend on the type of approach adopted. With the current study, the effect of error sources was characterized for an aortic case. In particular, the geometry of a patient-specific aorta structure was segmented at different phases of a cardiac cycle to be adopted in a computational analysis. Different levels of surface smoothing were imposed to define their influence on the numerical results. After this, three different simulation methods were imposed on the same geometry: a rigid wall computational fluid dynamics (CFD), a moving-wall CFD based on radial basis functions (RBF) CFD, and a fluid-structure interaction (FSI) simulation. The differences of the implemented methods were defined in terms of wall shear stress (WSS) analysis. In particular, for all the cases reported, the systolic WSS and the time-averaged WSS (TAWSS) were defined.


2021 ◽  
Vol 2131 (5) ◽  
pp. 052054
Author(s):  
D S Mizgirev ◽  
D V Vlasov ◽  
V N Vlasov

Abstract The problem of mathematical description of non-steady processes in hydrodynamic systems is currently relevant and requires early resolution. The description of cavitation as a non-steady process is one of the most important issues of hydrodynamics. In this paper, as a result of the analysis and generalization of a priori information, plus transformation of the basic equations describing cavitation processes, a number of expressions are obtained that reflect the behavior of the incompressible fluid main flow in a jet apparatus, taking into account the conduct of hydrodynamic cavitation in it. To create a cavitation process mathematical description, it is proposed to apply an empirical formula for determining the ejected flow pressure. The newly developed mathematical dependencies can be used in the design of jet devices (ejectors, cavitators, ejectors-cavitators) for various purposes in both marine and stationary coastal technological systems for processing fluid media. In particular, it is advisable to use them in the preparation and conditioning of drinking and industrial water, wastewater and oily water purification, etc.


2021 ◽  
Vol 2097 (1) ◽  
pp. 012012
Author(s):  
Lixing Zheng ◽  
Hongwei Hu ◽  
Changning Mi

Abstract The expansion of primary flow in the suction chamber of the CO2 two-phase ejector is investigated and its influences on the mixing characteristics are analyzed. An ejector model is developed, by constructing differential equations for mass, momentum and energy then get the governing equation. In the suction chamber, the expansion of primary flow and the compression of secondary flow are modeled along the flow path. Based on the constant-pressure mixing theory, the pressure equilibrium positions of two stream (namely at the inlet and inside of mixing chamber, respectively) are considered. The mass and energy transfer in the mixing chamber were analyzed by using the double-flow model formulation. The ejector performance parameters are obtained for the different operation conditions, and the distributions of temperature and velocity of two streams in the mixing chamber are presented. The simulation results showed the influence of primary flow expansion on the pressure lift ratio was relatively obvious, and the larger expansion distance was helpful to improve the mixing efficiency and decrease the thermodynamic entropy change during the mixing. Moreover, the temperature of secondary flow for lower primary flow pressure presented larger descent rates at the initial of mixing. This work is helpful for the improvement of ejector theoretical model and the optimization design.


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