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Principles of energy and momentum conservation to analyze and model air flow for perforated ventilation ducts / Modelling perforatred ventilation ducts

A theoretical model was developed to predict the air distribution pattern and thus to design perforated ventilation ducts equipped with a fan. The analysis of the air distribution pattern of such systems requires accurate measurement procedures. Several experimental methods were tested and compared. Accordingly, the piezometric flush taps and thermo-anemometer were selected to measure respectively the duct air pressure and the outlet air flow. / Based on the equations of energy and momentum conservation, a model was formulated to predict the air flow performance of perforated ventilation ducts and to evaluate the outlet discharge angle and the duct regain coefficients without evaluating frictional losses. The basic assumptions of the model were validated by experimentally proving the equivalence of the friction losses expressed in the 2 cited equations. When compared to experimental results measured from four wooden perforated ventilation ducts with aperture ratios of 0.5, 1.0, 1.5, and 2.0, the model predicted the outlet air flow along the full length of perforated duct operated under turbulent flow conditions with a maximum error of 9%. The regain coefficient and the energy correction factor were equal to one, and the value of the discharge coefficient remained constant at 0.65, along the full length of the perforated duct. The outlet air jet discharge angle varied along the entire duct length, and was not influenced by friction losses for turbulent flow. / Assuming a common effective outlet area, the model was extended to match the performance of the fan and the perforated duct and to determine their balance operating point.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.42024
Date January 1996
CreatorsEl Moueddeb, Khaled.
ContributorsBarrington, Suzelle F. (advisor)
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageDoctor of Philosophy (Department of Agricultural and Biosystems Engineering.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 001554337, proquestno: NQ29929, Theses scanned by UMI/ProQuest.

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