Hydraulics of microtube emitters: a dimensional analysis approach

Vekariya, P. B.; Subbaiah, R.; Mashru, H. H.

doi:10.1007/s00271-010-0240-6

Cited by 30 publications

(28 citation statements)

References 11 publications

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“…Dimensional analysis is a useful tool for developing predictive equations, which reduces the physical quantities to dimensionless groups called Π terms (VEKARIYA et al, 2011). The Π theorem enables the organisation of experimental runs and the analysis of measurements by dimensionless groups.…”

Section: Model Developmentmentioning

confidence: 99%

“…The Borda-Carnot equation (equation 4) enables quantification of head losses caused by a sudden expansion or contraction along a pipeline: Dimensional analysis is a simple, clear and intuitive method for determining the functional dependence of physical quantities that influence a process (VEKARIYA et al, 2011). The aim of this work was to develop a model based on dimensional analysis for calculating head loss along laterals accounting for in-line drippers.…”

Section: Introductionmentioning

confidence: 99%

“…Although drip irrigation systems have several advantages over other irrigation systems, the ideal water distribution along the lateral cannot be achieved due to variations in emitter discharge. These variations are influenced by operating pressure and water temperature (DOGAN & KIRNAK, 2010;BORSSOI et al, 2012); emitter manufacturing process; emitter clogging (TARCHITZKY et al, 2013;ZHOU et al, 2013) and pressure variations caused by slope (ZHU et al, 2010) and friction losses (RETTORE NETO et al, 2009;GOMES et al, 2010;VEKARIYA et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Modelling head loss along emitting pipes using dimensional analysis

et al. 2015

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Local head losses must be considered in estimating properly the maximum length of drip irrigation laterals. The aim of this work was to develop a model based on dimensional analysis for calculating head loss along laterals accounting for in-line drippers. Several measurements were performed with 12 models of emitters to obtain the experimental data required for developing and assessing the model. Based on the Camargo & Sentelhas coefficient, the model presented an excellent result in terms of precision and accuracy on estimating head loss. The deviation between estimated and observed values of head loss increased according to the head loss and the maximum deviation reached 0.17 m. The maximum relative error was 33.75% and only 15% of the data set presented relative errors higher than 20%. Neglecting local head losses incurred a higher than estimated maximum lateral length of 19.48% for pressure-compensating drippers and 16.48% for non pressure-compensating drippers. KEYWORDS

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Section: Model Developmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modelling head loss along emitting pipes using dimensional analysis

et al. 2015

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“…Moreover, the model equation used for microsprinkler model C nozzle underestimated the head loss on the lateral line, which has the average flow equal to the mean operating flow laboratory-estimated (Table 4). Furthermore, coefficient of flow-rate variation (CVq) were lower than 5.5% and acceptable (SOUZA et al, 2009;VEKARIYA et al, 2011;ZHANG et al, 2013;MATTAR et al, 2014). This low variation is similar to pressure-compensating nozzles (LI et al, 2007).…”

Section: Field Experime Ntmentioning

confidence: 99%

Pressure compensating microsprinklers using microtube as a flow controller

Almeida

Botrel³

et al. 2016

Eng. Agríc.

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ABSTRACT:Microsprinkler non-pressure compensating nozzles usually show water flow variation along the lateral line. This study aimed at adapting microtubes into non-c ompe nsating system of microsprinklers previous installed in the field, as a self-compensated nozzle, to improve the flow uniformity along the lateral line. Microtubes were adapted to three types of commercial microsprinklers. Tests were conducted, both in the laboratory and in field, to evaluate the microsprinkler performance at four different flows (40, 50, 60 and 70 L h -1 ) under pressure head range from 75 to 245 kPa. Nozzles presented coefficient of flow-rate variation (CVq) lower than 5.5% and distribution uniformity (DU) greater than 95%, which are classified as excellent. The original spatial water distribution of the microsprinkler did not change by using microtube as a nozzle. This device adapted to non-pressure compensating microsprinklers are functional and operate effectively with flows ranging up to 70 L h -1 . Small variations at microsprinkler flows along the lateral line can occur, however, at random manner, which is common for pressure-compensating nozzles. Therefore, the microtube technique is able to control pressure variation in microsprinklers.KEYWORDS: microtube nozzles, micro-irrigation, lateral design. MICROASPERSORES AUTOCOMPENSANTES UTILIZANDO MICROTUBOS

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“…Structural design, hydraulic performance analysis and flow mechanism research of the emitter are based on the theory of hydromechanics and hydraulics [1]. The experimental test [2][3][4], CFD numerical simulation [5][6][7][8], PIV flow field observation [9][10][11] and other methods are adopted to study the emitter.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of numerical simulation accuracy for two-ways mixed flow drip irrigation emitter based on CFD

Ge¹,

Dan²,

Wen³

et al. 2017

IJHT

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In order to evaluate the accuracy and applicability of the CFD numerical simulation method, we taken new two-ways mixed flow drip irrigation emitter as the research object, designed three kinds of emitter prototypes, and put forward the evaluation methods of the macroscopic flow rate index and the microscopic flow velocity index. According to the test results of flow rate and flow velocity by experiment and Particle Image Velocimetry (PIV) technology, analyzing the error of three kinds of wall function and seven classes physical models. The analysis results show that taking the macroscopic flow rate index as the evaluation standard, and numerical simulation accuracy of the enhanced wall function is higher and better. Comprehensive analysis of seven classes physical model by using the enhanced wall show that the average relative errors of the Standard k-ε model, RNG k-ε model, Standard k-ω model, SST k-ω model are smaller, followed by 2.16%, 1.47%, 1.84% and 1.90%, but RNG k-ε model has better simulation accuracy. Taking the microscopic flow velocity index as evaluation standard, the average relative errors are 3.42%, 2.68%, 2.34% and 1.81%, while the SST k-ω model has better simulation accuracy. Comprehensive evaluating two indexes, when the weight coefficient were taken at 0.5, respectively, the average relative error of SST k-ω model is calculated to be 1.85%, which is more suitable for the numerical simulation of emitter. The accuracy and applicability of various simulation methods are considered in the calculation of the flow rate and flow velocity, and the analysis of microscopic flow field.

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Hydraulics of microtube emitters: a dimensional analysis approach

Cited by 30 publications

References 11 publications

Modelling head loss along emitting pipes using dimensional analysis

Modelling head loss along emitting pipes using dimensional analysis

Pressure compensating microsprinklers using microtube as a flow controller

Evaluation of numerical simulation accuracy for two-ways mixed flow drip irrigation emitter based on CFD

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