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Main Title: Turbulence model performance for ventilation components pressure losses
Author(s): Tawackolian, Karsten
Kriegel, Martin
Type: Article
Abstract: This study looks to find a suitable turbulence model for calculating pressure losses of ventilation components. In building ventilation, the most relevant Reynolds number range is between 3×10 4 and 6×10 5 , depending on the duct dimensions and airflow rates. Pressure loss coefficients can increase considerably for some components at Reynolds numbers below 2×10 5 . An initial survey of popular turbulence models was conducted for a selected test case of a bend with such a strong Reynolds number dependence. Most of the turbulence models failed in reproducing this dependence and predicted curve progressions that were too flat and only applicable for higher Reynolds numbers. Viscous effects near walls played an important role in the present simulations. In turbulence modelling, near-wall damping functions are used to account for this influence. A model that implements near-wall modelling is the lag elliptic blending k-ε model. This model gave reasonable predictions for pressure loss coefficients at lower Reynolds numbers. Another example is the low Reynolds number k-ε turbulence model of Wilcox (LRN). The modification uses damping functions and was initially developed for simulating profiles such as aircraft wings. It has not been widely used for internal flows such as air duct flows. Based on selected reference cases, the three closure coefficients of the LRN model were adapted in this work to simulate ventilation components. Improved predictions were obtained with new coefficients (LRNM model). This underlined that low Reynolds number effects are relevant in ventilation ductworks and give first insights for suitable turbulence models for this application. Both the lag elliptic blending model and the modified LRNM model predicted the pressure losses relatively well for the test case where the other tested models failed.
Subject(s): CFD
model calibration
turbulence model
Issue Date: 25-Jun-2021
Date Available: 6-Dec-2021
Language Code: en
DDC Class: 620 Ingenieurwissenschaften und zugeordnete Tätigkeiten
Sponsor/Funder: BMWi, 03ET1606A, EnOB: LuftKonVerTeR - Berechnungs- und Bewertungsgrundlagen für den dynamischen Betrieb von Lüftungssystemen, bestehend aus RLT-Anlage (Konditionierung) und Kanalnetz (Verteilung) zur Steigerung der Energieeffizienz im Teillastbetrieb. Teilvorhaben: Verteilung
TU Berlin, Open-Access-Mittel – 2021
Journal Title: Building Simulation
Publisher: Springer Nature
Volume: 15
Issue: 3
Publisher DOI: 10.1007/s12273-021-0803-x
Page Start: 389
Page End: 399
EISSN: 1996-8744
ISSN: 1996-3599
TU Affiliation(s): Fak. 3 Prozesswissenschaften » Inst. Energietechnik » FG Gebäudeenergiesysteme
Appears in Collections:Technische Universität Berlin » Publications

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