Índice geométrico e perda de carga localizada em conexões de emissores "online"

Cardoso, Gabriel Greco de Guimarães; Klar, Antônio Evaldo

doi:10.1590/s0100-69162014000600008

Cited by 4 publications

(4 citation statements)

References 8 publications

(1 reference statement)

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“…K L data usually become stable from a Reynolds number of approximately 10,000, as observed by Rettore Neto et al (2009) and Zitterell et al (2009). Cardoso (2014) observed stable values of K L for Reynolds number of 20,000, studying pipe-connection sets. Above these values of Reynolds number, the effect of viscosity forces are assumed to be negligible in the flow and the local head loss coefficient (K L ) becomes almost exclusively dependent on the geometric characteristics of the piece (Rettore .…”

Section: Methodsmentioning

confidence: 70%

Local head loss caused in connections used in micro-irrigation systems

Bombardelli

Camargo

Frizzone

et al. 2019

Rev. bras. eng. agríc. ambient.

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Information about local head loss caused by connections employed in micro-irrigation systems is hard to be found in literature. The objective of this research was to experimentally determine the local head losses in connections commonly used in micro-irrigation and propose mathematical models using the theorem of Buckingham. The methodology of tests was based on international standards. The tests were carried out under controlled inlet pressure, at 150 kPa, and five to ten units of each connection model were tested. The curves relating flow and head losses were drawn based on 15 flow conditions, obtained under increase and decrease of flow rate. For each condition, 30 points were collected resulting in a sample size of 900 points in each test. For each connection model evaluated, the following information was obtained: curves of local head loss as a function of flow rate and of local head loss coefficient (KL). The obtained values of KL ranged from 2.72 to 24.16, which become constant for Reynolds number higher than 10,000. The sensitivity of the coefficient related to a ratio of the internal sections in the connections was also verified. The flow exponents presented values close to the one applied by the Darcy-Weisbach equation (m = 2). The models developed for the connections presented a satisfactory performance.

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Section: Methodsmentioning

confidence: 70%

Local head loss caused in connections used in micro-irrigation systems

Bombardelli

Camargo

Frizzone

et al. 2019

Rev. bras. eng. agríc. ambient.

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“…In the case of online drippers localized pressure loss can influence the phenomenon observed in the last sections of the lateral lines, whose drippers used tap water (Figure 4C and 4D). In a comparative study of loss of load between smooth hoses and hoses with online drippers, Cardoso & Klar (2014) observed local load losses in online drippers up to 62% due to the connections of this type of drippers. For all hose diameters tested by the authors, the type of connection that caused the greatest load loss was that of the self-compensating dripper of double side outlet (Type D).…”

Section: Resultsmentioning

confidence: 98%

Statistical Process Control in the Assessment of Drip Irrigation Using Wastewater

et al. 2018

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The aim of this study was to evaluate drip irrigation as a process, by monitoring the average flow applied by the emitter using tools of statistical quality control. Four kinds of drippers were selected, two inline labyrinth type and two online where one of the inline emitters was not self-compensating and the other, self-compensating emitter. The system was installed in the field and tested for 85 hours, using three kinds of treated domestic sewage effluents and tap water. The system was under statistical control when the emitters were new, however none of the drippers reaches the manufacturer´s specification for average flow. The online drippers showed more dispersion for individual flow measurements and the non-self-compensating inline dripper was more accurately for this variable. After the end of experiment, irrigation process was not under statistical control for any kind of emitter. When using treated wastewater effluents for irrigation we recommend a first evaluation before 7 working hours, to implement appropriated correcting procedures to reduce clogging and as a result, maintain the process quality.

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“…The method of estimating the emitter's local head loss was based on the Obstruction Index -OI (Alves and Porto, 2002;Cardoso and Klar, 2014), according to Equations 2, 3, and 4.…”

Section: Methodsmentioning

confidence: 99%

“…Laperuta Neto et al (2011) obtained local head for tablet type emitters in a hose with an average diameter of 14.45 mm in the order of 23% of the total head loss. The emitter labyrinth configuration and its dimensions determine the interference degree in the flow and the magnitude of the local head loss (Gomes et al, 2010;Cardoso and Klar, 2014).…”

Section: Simulationsmentioning

confidence: 99%

Effect of allowable flow-rate variation and local head loss on maximum length of non-pressure compensated drip tape

Andrade¹,

Saad²,

Cosmo³

et al. 2021

Rev. ambiente água

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A challenge for the design of drip irrigation systems with non-pressure compensated emitters is to increase the maximum length of the lateral lines without significantly reducing water application uniformity. This work evaluated the effect of the flow-rate variation and the local head loss in the maximum length of drip tape with a non-pressure compensated flat emitter. The tests were carried out in a laboratory, using a collapsible drip tape non-pressure compensated in three 50-meter segments. The production line was configured to generate drip tapes without insertion of emitters and with closed emitters (0.30 m spacing). The experimental local head loss was compared with the Darcy-Weisbach equation's estimates using the Blasius friction factor. In the sequence, simulations were generated for the flow-rate variations of 10 and 20% for the emitter spacings of 0.30, 0.40, and 0.50m. The results showed that the local head loss had little influence on the lateral line's maximum length, generating variations of 2.5% on average. However, increasing the allowable flow rate variation from 10 to 20% resulted in a 34% increase in the lateral line maximum length. Also, the reduction in uniformity coefficients was less than 5%, enabling the indexes to remain above 90%. The adoption of higher flow rate variation values allowed gains in the lateral line length with a small decrease in uniformity, making it an alternative to reduce design and operational costs.

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Índice geométrico e perda de carga localizada em conexões de emissores "online"

Cited by 4 publications

References 8 publications

Local head loss caused in connections used in micro-irrigation systems

Local head loss caused in connections used in micro-irrigation systems

Statistical Process Control in the Assessment of Drip Irrigation Using Wastewater

Effect of allowable flow-rate variation and local head loss on maximum length of non-pressure compensated drip tape

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