Measurement of airflow pattern induced by ceiling fan with quad-view colour sequence particle streak velocimetry

Airflow patterns are essential for heating, ventilation and air conditioning (HVAC) systems. Traditional HVAC systems are predesigned and operated using a fixed airflow pattern. However, the indoor occupancy and heat source always vary and therefore, the fixed flow pattern cannot efficiently maintain the required indoor environment conditions. In this study, a novel Adjustable Fan Network (AFN) for improving airflow pattern manoeuvrability is proposed. It integrates multiple small and adjustable axial fans into an AFN, enabling it to change the airflow pattern based on the actual demand with only one set of equipment. Further, the outflow characteristics of two types of axial fans were measured using a quad-view colour sequence particle streak velocimetry (CSPSV) in a test chamber. The ventilation system was then designed based on typical scenarios. Finally, the performance of the AFN was evaluated under different scenarios using a quad-view CSPSV. Based on the results, it was evident that the AFN can provide a better direct supply of air to the occupied zone under different scenarios. With the growing demand for personal thermal comfort and energy-saving in HVAC systems, the novel AFN system has a great potential to be a highly controllable terminal for demand-oriented ventilation.

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Airflow pattern induced by ceiling fan under different rotation speeds and blowing directions

Indoor and Built Environment ◽

10.1177/1420326x19890054 ◽

2019 ◽

Vol 29 (10) ◽

pp. 1425-1440 ◽

Cited By ~ 2

Author(s):

Huan Wang ◽

Maohui Luo ◽

Guijin Wang ◽

Xianting Li

Keyword(s):

New Technology ◽

Three Dimensional ◽

Air Conditioning System ◽

Airflow Pattern ◽

Room Size ◽

Colour Sequence ◽

Air Mixing ◽

Particle Streak Velocimetry ◽

Air Speed ◽

Velocity Turbulence

Ceiling fans have been widely used as effective cooling and air mixing method for building environment conditioning. Understanding its airflow characteristics can be helpful to utilize ceiling fan or integrate it with background air conditioning system. However, the airflow induced by ceiling fan has different flow patterns under different rotating speeds and blowing directions. To date, it is still challenging to capture those complicated airflow fields in room scale. In this study, the airflow pattern induced by a ceiling fan was measured with a new technology, quad-view colour sequence particle streak velocimetry. A series of isothermal experiments were conducted under five rotation speed levels with downward and upward blowing directions in a room-size (4 m × 2.5 m × 3 m) chamber. Based on comprehensive three-dimensional three-component vector measurement results, the average velocity, turbulence intensity and vorticity on the middle section were calculated and used to analyse airflow patterns induced by ceiling fan. The results show that the blowing direction of the fan determines the indoor airflow pattern. When blowing downward, the flow will cause high diversion between jet core under the fan blades and surrounding region. While for upward blowing, the air speed in lower part of the room is much lower but pretty uniform. The detailed measured airflow fields can serve as reference for ceiling fan design and operation.

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A colour-sequence enhanced particle streak velocimetry method for air flow measurement in a ventilated space

Building and Environment ◽

10.1016/j.buildenv.2016.11.015 ◽

2017 ◽

Vol 112 ◽

pp. 77-87 ◽

Cited By ~ 8

Author(s):

Huan Wang ◽

Xianting Li ◽

Xiaoliang Shao ◽

Baolong Wang ◽

Yanqing Lin

Keyword(s):

Flow Measurement ◽

Air Flow ◽

Colour Sequence ◽

Particle Streak Velocimetry

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Numerical assessment of natural respiration and particles deposition in the computed tomography scan airway with a glomus tumour

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/09544089211024063 ◽

2021 ◽

pp. 095440892110240

Author(s):

Digamber Singh

Keyword(s):

Computed Tomography ◽

Respiratory Tract ◽

Particle Deposition ◽

Flow Characteristics ◽

Glomus Tumour ◽

Computed Tomography Scan ◽

Human Respiratory Tract ◽

Airflow Pattern ◽

Human Airways ◽

Tomography Scan

The human respiratory tract has a complex airflow pattern. If any obstruction is present in the airways, it will change the airflow pattern and deposit particles inside the airways. This is the concern of breath quality (inspired air), and it is decreasing due to the unplanned production of material goods. This is a primary cause of respiratory illness (asthma, cancer, etc.). Therefore, it is important to identify the flow characteristics in the human airways and airways with a glomus tumour with particle deposition. A numerical diagnosis is presented with an asymmetric unsteady-state light breathing condition (10 l/min). An in vitro human respiratory tract model has been reconstructed using computed tomography scan techniques and an artificial glomus tumour developed 2 cm above a carina on the posterior wall of the trachea. The transient flow characteristics are numerically simulated with a realizable (low Reynolds number) k–ɛ turbulence model. The flow disturbance is captured around the tumour, which influenced the upstream and downstream of the flow. The flow velocity pattern, wall shear stress and probable area of inflammation (hotspot) due to suspended particle deposition are determined, which may assist doctors more effectively in aerosol therapy and prosthetics of human airways illness.

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Airtightness impact on energy needs and airflow pattern: a numerical evaluation for mechanically ventilated dwellings in France

International Journal of Ventilation ◽

10.1080/14733315.2016.1203608 ◽

2016 ◽

Vol 15 (2) ◽

pp. 134-150 ◽

Cited By ~ 4

Author(s):

F. Richieri ◽

B. Moujalled ◽

T. Salem ◽

F.R. Carrié

Keyword(s):

Numerical Evaluation ◽

Mechanically Ventilated ◽

Airflow Pattern ◽

Energy Needs

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Airflow pattern and performance of attached ventilation for two types of tiny spaces

Building Simulation ◽

10.1007/s12273-021-0876-6 ◽

2022 ◽

Author(s):

Haiguo Yin ◽

Yanyan Li ◽

Da Zhang ◽

Yuekun Han ◽

Jiali Wang ◽

...

Keyword(s):

Airflow Pattern ◽

And Performance

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Impact of posterior septum resection on nasal airflow pattern and warming function

Acta Oto-Laryngologica ◽

10.1080/00016489.2019.1688388 ◽

2019 ◽

Vol 140 (1) ◽

pp. 51-57 ◽

Cited By ~ 1

Author(s):

Lifeng Li ◽

Nyall R. London ◽

Hongrui Zang ◽

Demin Han

Keyword(s):

Nasal Airflow ◽

Airflow Pattern ◽

Posterior Septum

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Droplets and Aerosols Generated by Singing and the Risk of Coronavirus Disease 2019 for Choirs

Clinical Infectious Diseases ◽

10.1093/cid/ciaa1241 ◽

2020 ◽

Author(s):

Prateek Bahl ◽

Charitha de Silva ◽

Shovon Bhattacharjee ◽

Haley Stone ◽

Con Doolan ◽

...

Keyword(s):

Infection Rates ◽

Choral Singing ◽

Airflow Pattern ◽

High Infection

Abstract Choral singing has become a major risk during the coronavirus disease 2019 (COVID-19) pandemic due to high infection rates. Our visualization and velocimetry results reveal that the majority of droplets expelled during singing follow the ambient airflow pattern. These results point toward the possibility of COVID-19 spread by small airborne droplets during singing.

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Airflow Pattern Test Procedure

Validation Standard Operating Procedures ◽

10.3109/9781420009415-152 ◽

2006 ◽

pp. 1025-1028

Keyword(s):

Test Procedure ◽

Airflow Pattern

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A STRATEGY FOR IDENTIFYING FLUORESCENCE INTENSITY PROFILES OF SINGLE ROD-SHAPED CELLS

Journal of Bioinformatics and Computational Biology ◽

10.1142/s0219720012500242 ◽

2013 ◽

Vol 11 (02) ◽

pp. 1250024 ◽

Cited By ~ 1

Author(s):

ALEXANDRA HERZOG ◽

BJÖRN VOSS ◽

DANIELA KEILBERG ◽

EDINA HOT ◽

LOTTE SØGAARD-ANDERSEN ◽

...

Keyword(s):

Fluorescence Intensity ◽

Cell Biology ◽

Imaging System ◽

Signal To Noise Ratio ◽

Single Cells ◽

Image Data ◽

Cell Orientation ◽

Cell Axis ◽

Particle Streak Velocimetry ◽

User Friendly

The extraction of fluorescence intensity profiles of single cells from image data is a common challenge in cell biology. The manual segmentation of cells, the extraction of cell orientation and finally the extraction of intensity profiles are time-consuming tasks. This article proposes a routine for the segmentation of single rod-shaped cells (i.e. without neighboring cells in a distance of the cell length) from image data combined with an extraction of intensity distributions along the longitudinal cell axis under the aggravated conditions of (i) a low spatial resolution and (ii) lacking information on the imaging system i.e. the point spread function and signal-to-noise ratio. The algorithm named cipsa transfers a new approach from particle streak velocimetry to cell classification interpreting the rod-shaped as streak-like structures. An automatic reduction of systematic errors such as photobleaching and defocusing is included to guarantee robustness of the proposed approach under the described conditions and to the convenience of end-users unfamiliar with image processing. Performance of the algorithm has been tested on image sequences with high noise level produced by an overlay of different error sources. The developed algorithm provides a user-friendly, stand-alone procedure.

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