Download or read book Residence Time Distributions and Computational Fluid Dynamics to Characterize Dilution Ventilation in a Confined Space Model written by Ravi Nabar and published by . This book was released on 1994 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Air Pollution written by and published by . This book was released on 1999 with total page 1120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Recent Advances in Urban Ventilation Assessment and Flow Modelling written by Riccardo Buccolieri and published by MDPI. This book was released on 2019-04-23 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains twenty-one original papers and one review paper published by internationally recognized experts in the Atmosphere Special Issue "Recent Advances in Urban Ventilation Assessment and Flow Modelling", years 2017–2019. The Special Issue includes contributions on recent experimental and modelling works, techniques, and developments mainly tailored to the assessment of urban ventilation on flow and pollutant dispersion in cities. The study of ventilation is of critical importance, as it addresses the capacity with which a built urban structure is capable of replacing the polluted air with ambient fresh air. Here, ventilation is recognized as a transport process that improves local microclimate and air quality and closely relates to the term “breathability”. The efficiency with which street canyon ventilation occurs depends on the complex interaction between the atmospheric boundary layer flow and the local urban morphology. The individual contributions to this Issue are summarized and categorized into four broad topics: (1) outdoor ventilation efficiency and application/development of ventilation indices, (2) relationship between indoor and outdoor ventilation, (3) effects of urban morphology and obstacles to ventilation, and (4) ventilation modelling in realistic urban districts. The results and approaches presented and proposed will be of great interest to experimentalists and modelers, and may constitute a starting point for the improvement of numerical simulations of flow and pollutant dispersion in the urban environment, for the development of simulation tools, and for the implementation of mitigation strategies.

Download or read book Characterizing Positive Pressure Ventilation Using Computational Fluid Dynamics written by and published by . This book was released on 2003 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Airflow and Temperature Distribution in Rooms with Displacement Ventilation written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Airflow and Temperature Distribution in Rooms with Displacement Ventilation written by T. V. (Aalborg Universitetscenter Jacobsen (Inst. forBygningsteknik (DK)).) and published by . This book was released on 1993 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Natural Ventilation for Infection Control in Health care Settings written by Y. Chartier and published by World Health Organization. This book was released on 2009 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: This guideline defines ventilation and then natural ventilation. It explores the design requirements for natural ventilation in the context of infection control, describing the basic principles of design, construction, operation and maintenance for an effective natural ventilation system to control infection in health-care settings.

Download or read book Modeling and Characterizing Bi directional Airflow in Natural Ventilation written by Qin Zhang (S.M.) and published by . This book was released on 2016 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Modeling and Evaluation of Personal Displacement Ventilation System for Improving Indoor Air Quality written by Yue Xu and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research aims at evaluating a new ventilation concept: personal displacement ventilation (PDV) for improving indoor air quality. The new ventilation method combines room displacement ventilation with task ventilation, the latter being directed at controlling air quality and comfort in the microenvironment where the building occupant is working, with the premise that such directed ventilation will maintain air quality where it matters. This approach could lead to improved ventilation system design that could even provide individual control of indoor microclimate. The effectiveness of PDV was studied by using computational fluid dynamics (CFD) modeling and rigorous validation experiments. First, a small office setup was built in a controlled environmental chamber. Three PDV cases with different locations of contaminant source and one general displacement ventilation (DV) case were investigated. Spatial distributions of airflow, temperature, and hypothetical pollutant distributions were measured. The measured data were then used to evaluate the performance of PDV against defined indoor air quality and thermal comfort criteria, and to validate the CFD model. The validated CFD program was further used to study PDV under various conditions. This study found that basic equipped PDV acts no different from DV from airflow pattern2s point of view. Due to the lack of heat generation around occupant2s legs, local buoyancy effect is not strong enough to attract supply air, which is generated from diffuser nearby, to join in the plume around occupant. However, auxiliary activities adjusting the direction of supply air and adding high panels around person can improve the fraction of supply air to join the plume around person or decrease the average contaminant concentration in breathing zone.

Download or read book Investigation of Airflow in a Room with Displacement Ventilation by Means of a CFD model Computational Fluid Dynamics written by T. V. Jacobsen and published by . This book was released on 1994 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Fluid Dynamics Simulations on the Natural Ventilation Bahaviour Within a Building Cluster written by On-Pong Cheung and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Computational Fluid Dynamics Simulations on the Natural Ventilation Bahaviour Within a Building Cluster" by On-pong, Cheung, 張安邦, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. DOI: 10.5353/th_b4559008 Subjects: Fluid dynamics - Mathematical models Natural ventilation - Mathematical models

Download or read book Computational Fluid Dynamics in Ventilation written by P. V. Nielsen and published by . This book was released on 1994 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparative Analysis of Industrial Ventilation Schemes Via Computational Fluid Dynamics written by Paulo César Tabares Velasco and published by . This book was released on 2005 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Fluid Dynamics Modelling of Displacement Natural Ventilation written by Yingchun Ji and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural ventilation is widely recognised as contributing towards low-energybuilding design. The requirement to reduce energy usage in new buildings hasrejuvenated interest in natural ventilation. This thesis deals with computer modelling of natural displacement ventilationdriven either by buoyancy or buoyancy combined with wind forces. Twobenchmarks have been developed using computational fluid dynamics (CFD)in order to evaluate the accuracy with which CFD is able to model naturaldisplacement ventilation flow. The first benchmark considers the naturalventilation of a single ventilated space with high and low level openingsconnected to the exterior driven by combined forces of wind and buoyancy. The second benchmark considers natural ventilation flow in a single spaceconnected to an atrium driven by pure buoyancy. Simulation results of keyventilation parameters (stratification depth, temperature gradient andventilation flow rate) have been compared with analytical and experimentalmodels and close agreements have been achieved. The two benchmarks are defined using the RNG k-epsilon turbulence model. A pressure boundary is applied onto the ventilation openings directly and aporous medium boundary is used to assist the development of the thermalplume. This method has proved to be robust and the close agreementbetween the three modelling techniques indicates that CFD is able to modelnatural ventilation flows in simple geometries with acceptable accuracy andreliability. Using the benchmarks the influences of key CFD modelling parameters andbuilding design issues have been investigated. For example, representingopenings, heat source representation, stack height, and air inlet strategies. Natural displacement ventilation of a multi-storey building comprising anatrium is also addressed. Simple analytical models have been developed todescribe the key air flow features within the ventilation system.

Download or read book Residence Time Distributions in Annular Two phase Horizontal Flow written by George Artell Smith and published by . This book was released on 1964 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Determining Pressure Coefficients for Natural Ventilation Purproses by Computational Fluid Dynamics Modeling written by Timothy Richard Eric LaFrance and published by . This book was released on 2006 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This research is concerned with improving the control of natural ventilation. Pressure coefficients at the vent openings of a naturally ventilated six bay greenhouse were found for varying wind directions, wind speeds, and vent opening configurations using Computational Fluid Dynamics (CFD). These pressure coefficients can be used in a quick running program developed by Brockett and Aibright (1987) for real time control of ventilation rates. The real time control program uses sensors to detect climatic variables and solves a series of equations based on the pressure difference method to determine air flow through vent openings. The program then adjusts vent openings to control the airflow through each vent. The program has been shown to accurately predict mass flow rates given good pressure coefficients. Validating the accuracy of the pressure coefficients was done by comparing air exchange rates and mass flow rates through each vent opening using results from both the real time control program with the CFD computed pressure coefficients as input and results from the CFD simulations. The results were compared under different scenarios, and there was a good agreement between the two programs in determining both total air exchange rates (R2=O.98) and mass flow through vent openings (R2=O.97)

Download or read book Computational Fluid Dynamics Study of Ventilated Cages for Laboratory Animals written by Ashutosh Pandey and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The purpose of this study was to construct a computational fluid dynamics (CFD) model of a rodent cage to analyze the distribution of various air quality indicators (e.g., carbon dioxide, ammonia, and humidity) in the cage environment. On the subject of ventilation, the most widely used sources of performance criteria for research animal facility ventilation systems are the Guide for the Care and Use of Laboratory Animals, Institute of Laboratory Animal Resources and the American Society of Heating Refrigerating and Air Conditioning Engineers Applications and Fundamentals Handbooks. Most of these guidelines are based on the results of several studies undertaken previously.