title: Evaluation of power consumption of paddle wheel in an open raceway pond.
abstract: Open raceway ponds are widely adopted in microalgae cultivation. Paddle wheels consume the most part of power during the process of cultivation in open raceway ponds. The configuration of blades directly determines power consumption for paddle wheels. In this work, power consumption of four blades configurations was determined in a bench-scale open raceway pond of 2.2 m(2). The effect of blades configuration, the influence of filling levels from 5 to 15 cm and influence of rotational speeds from 7 to 15 r min(-1) on shaft power consumption (P(S)), fluid velocity (U(c)) and paddle wheel efficiency (η) was investigated. Results demonstrated that flat blades were the most efficient configuration. Higher culture depth led to larger U(c), more P(s) and larger η, especially when blades were not totally immerged in water. Under the same filling level and rotational speed, the value of P(S) decreases in the order: zigzagged, flat, forward-curved and back-curved, respectively. The zigzagged blades led to a larger U(c) at the culture depth of 5 cm, while flat and forward-curved blades drove a larger U(c) when culture depth was higher than 5 cm. The maximum value of η was 0.50 with flat blades at 11 r min(-1) and 15 cm of culture depth. Empirical correlations of non-dimensional numbers related to operation parameters and blades geometry for four paddle wheel blades were also proposed.
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
authors.forename: Yanxi
authors.initials: Y
authors.lastname: Li
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Zhang
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Wang
authors.forename: Xia
authors.initials: X
authors.lastname: Wu
authors.forename: Wei
authors.initials: W
authors.lastname: Cong
mesh_terms: D001709:Biotechnology / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D058086:Microalgae / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D061005:Ponds / Q000382:microbiology*; D013997:Time Factors; D019415:Torque; D014865:Waste Disposal, Fluid / Q000295:instrumentation* / Q000379:methods*; D018508:Water Purification
chemical_list: D010100:Oxygen