Internal surface roughness of plastic pipes for irrigation

Abstract

A B S T R A C TAssuming that a roughness meter can be successfully employed to measure the roughness on the internal surface of irrigation pipes, this research had the purpose of defining parameters and procedures required to represent the internal surface roughness of plastic pipes used in irrigation. In 2013, the roughness parameter Ra, traditional for the representation of surface irregularities in most situations, and the parameters Rc, Rq, and Ry were estimated based on 350 samples of polyvinyl chloride (PVC) and low-density polyethylene (LDPE) pipes. Pressure losses were determined from experiments carried out in laboratory. Estimations of pressure loss varied significantly according to the roughness parameters (Ra, Rc, Rq, and Ry) and the corresponding pipe diameter. Therefore, specific values of roughness for each pipe diameter improves accuracy in pressure losses estimation. The average values of internal surface roughness were 3.334 and 8.116 µm for PVC and LDPE pipes, respectively. Rugosidade interna de tubos plásticos utilizados em irrigação R E S U M OObjetivou-se, no presente estudo, estabelecer os parâmetros de amplitude das irregularidades da superfície interna de tubos plásticos para irrigação, assim como procedimentos para sua obtenção e representação utilizando-se um rugosímetro de bancada. Durante o ano de 2013 foram avaliados 350 perfis de rugosidade de tubos de PVC e polietileno de baixa densidade (PEBDL), sendo determinados os parâmetros de rugosidade Ra, clássico para a representação das irregularidades de superfícies na maioria das situações, além dos parâmetros adicionais Rc, Rq e Ry. Determinações hidráulicas de perda de carga foram realizadas em laboratório para comparação com a perda de carga obtida pela aplicação dos parâmetros de rugosidade. Evidenciou-se diferença significativa de desempenho estatístico dos parâmetros de rugosidade (Ra, Rq, Rc e Ry) de acordo com o diâmetro do tubo e, portanto, constatou-se que a adoção de valores de rugosidade específicos para cada diâmetro contribui para a exatidão das estimativas de perda de carga. A rugosidade média para tubos de PVC e PEBDL foi 3,334 e 8,116 µm, respectivamente.

Iterative calculation of local head loss coefficient of emitters in lateral lines

“…6), based on an absolute roughness (e) for PVC pipes of 0.00001 m (Carvalho & Oliveira, 2008). According to Rocha et al (2017) and Minhoni et al (2020), this equation can be applied to regimes laminar flow, hydraulically smooth turbulent flow, transitional flow, and rough turbulent flow. Furthermore, to quantify the Reynolds number (Eq.…”

The Performance of Explicit Formulas for Determining the Darcy-Weisbach Friction Factor

“…The ɛ/D values were based on the pipe materials most often used in irrigation and hydraulic projects, which include polyvinyl chloride (PVC), linear low-density polyethylene (LLDPE), galvanized steel and aluminum. The ε/D values for PVC and LLDPE were from Rocha et al (2017), as specified in Table 2, and the values for galvanized steel (0.0007 m) and aluminum (0.0010 m) were obtained from Testezlaf (1982). Moreover, based on Moody's (1944) diagram, values of 0.000001 m, 0.000005 m and 0.00001 m were considered.…”

Construction and Analysis of Plastic Extruder Machine for Polyethylene Plastic Waste

“…Surface roughness test for plastic composites by applying an optical method was measured [21]. Furthermore, plastic pipes that were used for irrigation were calculated experimentally using internal surface roughness test [22].…”