2026-09-18T20:15:35Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/1064272021-07-05T14:03:20Zcom_1721.1_97716com_1721.1_7749com_1721.1_7582com_1721.1_7581col_1721.1_97717col_1721.1_131023
Leon R. Glicksman.
Zhang, Qin, Ph.D. Massachusetts Institute of Technology
Massachusetts Institute of Technology. Department of Architecture.
Massachusetts Institute of Technology. Department of Architecture
2017-01-12T18:33:02Z
2017-01-12T18:33:02Z
2016
2016
http://hdl.handle.net/1721.1/106427
967231227
Thesis: S.M., Massachusetts Institute of Technology, Department of Architecture, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 98-105).
Bi-directional airflow in natural ventilation is an essential but not-well-understood scenario due to the complexity of airflow patterns as well as the strong coupling effect between temperature and ventilation. Neglecting bi-directional natural ventilation will result in problematic solutions and inaccuracy in estimation of ventilation performance. This work is focused on filling the knowledge gap by understanding the bi-directional airflow using computational fluid dynamics (CFD). Two important scenarios are simulated and analyzed: 1. Two-zone model with pure buoyancy forces, 2. Multi-zone model with combined wind and buoyancy forces. In the 1st model, a new concept of "local discharge coefficient" is proposed for its consistency under different boundary conditions. The influence of radiative heat transfer on simulation accuracy and ventilation performance is also investigated. In the 2nd model, the transient behaviors of airflow and the dynamics of wind and buoyant forces are analyzed and characterized. A new physical model is proposed based on simplified assumptions and nondimensionalization. This model is able to predicting the transient behavior of multi-zonal ventilation that involves bidirectional airflow patterns. The result of this study is to be integrated in CoolVent, the software designed by Building Technology Lab.
by Qin Zhang.
S.M.
105 pages
eng
Massachusetts Institute of Technology
M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.
http://dspace.mit.edu/handle/1721.1/7582
Architecture.
Modeling and characterizing bi-directional airflow in natural ventilation
Thesis
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<Abstract>Bi-directional airflow in natural ventilation is an essential but not-well-understood scenario due to the complexity of airflow patterns as well as the strong coupling effect between temperature and ventilation. Neglecting bi-directional natural ventilation will result in problematic solutions and inaccuracy in estimation of ventilation performance. This work is focused on filling the knowledge gap by understanding the bi-directional airflow using computational fluid dynamics (CFD). Two important scenarios are simulated and analyzed: 1. Two-zone model with pure buoyancy forces, 2. Multi-zone model with combined wind and buoyancy forces. In the 1st model, a new concept of "local discharge coefficient" is proposed for its consistency under different boundary conditions. The influence of radiative heat transfer on simulation accuracy and ventilation performance is also investigated. In the 2nd model, the transient behaviors of airflow and the dynamics of wind and buoyant forces are analyzed and characterized. A new physical model is proposed based on simplified assumptions and nondimensionalization. This model is able to predicting the transient behavior of multi-zonal ventilation that involves bidirectional airflow patterns. The result of this study is to be integrated in CoolVent, the software designed by Building Technology Lab.</Abstract>
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