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Full-Text Articles in Engineering

Air Quality Near Busy Australian Roads Up To 10 Times Worse Than Official Figures, Hugh I. Forehead Jan 2020

Air Quality Near Busy Australian Roads Up To 10 Times Worse Than Official Figures, Hugh I. Forehead

SMART Infrastructure Facility - Papers

Air quality on Australia’s roads matters. On any given day (when we’re not in lockdown) people meet, commute, exercise, shop and walk with children near busy streets. But to date, air quality monitoring at roadsides has been inadequate. I and my colleagues wanted to change that. Using materials purchased from electronics and hardware stores for around A$150, we built our own air quality monitors. Our newly published research reveals how our devices detected particulate pollution at busy intersections at levels ten times worse than background levels measured at official air monitoring stations.


Assessing The Effects Of Mobility On Air Quality: The Liverpool Smart Pedestrian Project, Nicolas R. Verstaevel, Johan Barthelemy, Hugh I. Forehead, Bilal Arshad, Pascal Perez Jan 2020

Assessing The Effects Of Mobility On Air Quality: The Liverpool Smart Pedestrian Project, Nicolas R. Verstaevel, Johan Barthelemy, Hugh I. Forehead, Bilal Arshad, Pascal Perez

SMART Infrastructure Facility - Papers

With the drastic increase of their urban population, cities face huge challenges to maintain and update their infrastructures. Assessing in real time the effect of urban policies will be a key tool in the future of urban planning. In this paper, we discuss of mobility and its impact on air quality. We introduce a pilot project in which low cost IoT sensors are used to monitor flow of cars and pedestrians and concentration of particulate matters within the Australian city of Liverpool.


Air Void Detection Using Variational Mode Decomposition With Low Rank, Fok Hing Chi Tivive, Abdesselam Bouzerdoum, Shivakumar Karekal Jan 2020

Air Void Detection Using Variational Mode Decomposition With Low Rank, Fok Hing Chi Tivive, Abdesselam Bouzerdoum, Shivakumar Karekal

Faculty of Engineering and Information Sciences - Papers: Part B

This paper presents an air-void detection technique for air-coupled radar, which emits electromagnetic waves to interrogate an air-void inside a medium or between two media. The reflections from the air-medium interfaces are usually corrupted by air-coupling, antenna ringing, and internal reflections, rendering air-void detection very difficult or, in certain cases, impossible. The proposed method exploits the low-rank structure of the background clutter to suppress these nuisance signals. A variational mode decomposition model is developed to extract the backscattering at different air-medium interfaces as signal modes. Real experiments are conducted using a stepped frequency radar. The experimental results show that the …


Experimental Performance Analysis And Evaluation Of A Novel Frost-Free Air Source Heat Pump System, Zhihua Wang, Fenghao Wang, Zhenjun Ma, Mengjie Song, Wenke Fan Jan 2018

Experimental Performance Analysis And Evaluation Of A Novel Frost-Free Air Source Heat Pump System, Zhihua Wang, Fenghao Wang, Zhenjun Ma, Mengjie Song, Wenke Fan

Faculty of Engineering and Information Sciences - Papers: Part B

To tackle the problem of frosting occurred on the outdoor coil surface when an air source heat pump (ASHP) is operated in winter, a novel frost-free ASHP system has been developed. However, the dehumidification performance and the frost-free time of the system operated are highly dependent on the electronic expansion valve (EEV) opening of the 1st stage throttle. In addition, the coefficient of performance (COP) of the systems is controlled by the EEV opening of the 2nd stage throttle. Therefore, the objective of this study is to investigate the effect of the EEV opening on the system thermodynamic performance in …


Relationship Between Indoor Air Temperatures And Energy Bills For Low Income Homes In Australia, Clayton Mcdowell, Georgios Kokogiannakis, Laia Ledo Gomis, Paul Cooper Jan 2017

Relationship Between Indoor Air Temperatures And Energy Bills For Low Income Homes In Australia, Clayton Mcdowell, Georgios Kokogiannakis, Laia Ledo Gomis, Paul Cooper

Faculty of Engineering and Information Sciences - Papers: Part B

Energy poverty is a prevalent issue in Australia and other countries across the globe especially for people with a low income. This paper seeks to investigate the relationship of energy consumption and indoor air temperatures and is separated into 3 sections; a comparison of actual electricity consumption to energy benchmarks provided by the Australian Energy Regulator, monitoring results of living room air temperature for the winter of 2015, and an analysis of living room air temperatures versus electricity consumption. The results of a comparison of electricity consumption of 119 low income elderly peoples (60+) dwellings to that of the energy …


Development Of A Dynamic Model For A Hybrid Photovoltaic Thermal Collector - Solar Air Heater With Fins, Wenke Fan, Georgios Kokogiannakis, Zhenjun Ma, Paul Cooper Jan 2017

Development Of A Dynamic Model For A Hybrid Photovoltaic Thermal Collector - Solar Air Heater With Fins, Wenke Fan, Georgios Kokogiannakis, Zhenjun Ma, Paul Cooper

Faculty of Engineering and Information Sciences - Papers: Part A

A dynamic model for a hybrid Photovoltaic Thermal Collector-Solar Air Heater (PVT-SAH) with longitudinal fins was developed to enable assessment of the potential of the system to provide high temperature outlet air (60-90 °C) under dynamic boundary conditions. The model description includes the method for discretising the system into a number of control volumes, the energy balance equations for each control volume and the implementation of the numerical solution. Model validation has been successfully undertaken by using empirical verification of model predictions with an experimental facility and by comparing the model outputs with the reference data from the literature. The …


Thermal Comfort Evaluation Of A Mixed-Mode Ventilated Office Building With Advanced Natural Ventilation And Underfloor Air Distribution Systems, Xiang Deng, Georgios Kokogiannakis, Zhenjun Ma, Paul Cooper Jan 2017

Thermal Comfort Evaluation Of A Mixed-Mode Ventilated Office Building With Advanced Natural Ventilation And Underfloor Air Distribution Systems, Xiang Deng, Georgios Kokogiannakis, Zhenjun Ma, Paul Cooper

Faculty of Engineering and Information Sciences - Papers: Part A

This study uses field monitoring and post occupancy evaluation (POE) surveys to investigate the indoor thermal comfort of an office building that is located in subtropical zone. The building is special as it combines advanced natural ventilation (ANV) strategies and underfloor air distribution (UFAD) systems. A comparison between a static thermal comfort model and a dynamic thermal comfort model is also conducted. The results show that the thermal comfort conditions in the case study building are satisfactory in summer while in winter there is evidence of thermal discomfort. For the case study building, the static thermal comfort model gives outputs …


Indoor Air Temperature And Agitation Of Nursing Home Residents With Dementia, Federico Tartarini, Paul Cooper, Richard Fleming, Marijka Batterham Jan 2017

Indoor Air Temperature And Agitation Of Nursing Home Residents With Dementia, Federico Tartarini, Paul Cooper, Richard Fleming, Marijka Batterham

Faculty of Engineering and Information Sciences - Papers: Part B

This study aimed to determine the specific correlation between indoor air temperature and agitation of nursing home residents with dementia. Agitated behaviors of 21 residents, living in 1 nursing home, were assessed for a 10-month period using the Cohen-Mansfield Agitation Inventory (CMAI). The CMAI Total Frequency scores were found to increase significantly when indoor average temperatures deviated from 22.6°C. In addition, cumulative exposure to temperatures higher than 26°C and lower than 20°C was linearly correlated with CMAI Total Frequency scores. Results showed that agitated behaviors not only affected the person manifesting them but were found to be disruptive for other …


Impact Of A Pilot Draught Sealing Program On Public Housing Air Permeability, Craig G. Mclauchlan, Laia Ledo Gomis, Paul Cooper Jan 2017

Impact Of A Pilot Draught Sealing Program On Public Housing Air Permeability, Craig G. Mclauchlan, Laia Ledo Gomis, Paul Cooper

Faculty of Engineering and Information Sciences - Papers: Part B

Air tightness (or permeability) is a property of a building envelope that describes how air moves though it when subjected to a pressure difference (wind, stack effect, etc.), this impacts on building performance including energy usage, thermal comfort and air quality. The NSW Land and Housing Corporation (LAHC) implemented a pilot program of simple leak (or draught) sealing measures to improve air permeability and building performance on some of its domestic building stock. The effectiveness of this program was evaluated via blower door testing to international standards including measuring overall envelope permeability, and qualitative and quantitative investigation of the leakage …


Field Study Of Air Conditioning And Thermal Comfort In Residential Buildings, Jungsoo Kim, Richard De Dear, Tom Parkinson, Christhina Candido, Paul Cooper, Zhenjun Ma, Wasim Saman Jan 2016

Field Study Of Air Conditioning And Thermal Comfort In Residential Buildings, Jungsoo Kim, Richard De Dear, Tom Parkinson, Christhina Candido, Paul Cooper, Zhenjun Ma, Wasim Saman

Faculty of Engineering and Information Sciences - Papers: Part A

The aim of this study is to better understand the external and internal drivers that affect residential air-conditioning (A/C) use decisions and occupant comfort. Field observations were carried out using instrumental measurements and smartphone questionnaires, recording householder's A/C usage patterns, indoor/outdoor climatic factors, perception of thermal comfort and adaptive behaviours.


Development And Performance Evaluation Of A Liquid Desiccant Air Conditioning System With Hybrid Electrodialysis And Thermal Regeneration, Yi Guo, Zhenjun Ma, Ali Hussein Al-Jubainawi, Paul Cooper, Long D. Nghiem Jan 2016

Development And Performance Evaluation Of A Liquid Desiccant Air Conditioning System With Hybrid Electrodialysis And Thermal Regeneration, Yi Guo, Zhenjun Ma, Ali Hussein Al-Jubainawi, Paul Cooper, Long D. Nghiem

Faculty of Engineering and Information Sciences - Papers: Part A

Liquid desiccant air conditioning (LDAC) systems have gained increasing attention due to the improved energy performance and reduced environmental impacts. This paper presents an LDAC system using electrodialysis (ED) as well as low grade heat generated from a hybrid photovoltaic thermal and evacuated tube (PVT-ET) collector for liquid desiccant regeneration. As ED regenerator is a key component in the proposed system, a modified mathematical model is used to simulate the mass transfer of the ED stack. The performance of the model was validated using the experimental data generated based on a lab-scale experimental setup. It is shown that the model …


A Sensor Fault Detection Strategy For Air Handling Units Using Cluster Analysis, Rui Yan, Zhenjun Ma, Georgios Kokogiannakis, Yang Zhao Jan 2016

A Sensor Fault Detection Strategy For Air Handling Units Using Cluster Analysis, Rui Yan, Zhenjun Ma, Georgios Kokogiannakis, Yang Zhao

Faculty of Engineering and Information Sciences - Papers: Part A

Sensors are an essential component in the control systems of air handling units (AHUs). A biased sensor reading could result in inappropriate control and thereby increased energy consumption or unsatisfied indoor thermal comfort. This paper presents an unsupervised learning based strategy using cluster analysis for AHU sensor fault detection. The historical data recorded from sensors is first pre-processed to reduce the dimensions using principal component analysis (PCA). The clustering algorithmOrdering Points to Identify the Clustering Structure (OPTICS) is then employed to identify the spatial separated data groups (i.e. clusters),which possibly indicate the occurrence of sensor faults. The data points in …


Thermal Performance Evaluation And Optimal Design Of Buildings With Integrated Air-Based Photovoltaic Thermal Collectors And Phase Change Materials Using The Hooke-Jeeves Pattern Search Method, Wenye Lin, Zhenjun Ma, Paul Cooper Jan 2016

Thermal Performance Evaluation And Optimal Design Of Buildings With Integrated Air-Based Photovoltaic Thermal Collectors And Phase Change Materials Using The Hooke-Jeeves Pattern Search Method, Wenye Lin, Zhenjun Ma, Paul Cooper

Faculty of Engineering and Information Sciences - Papers: Part A

Over the last several decades, many low energy technologies have been developed and deployed to reduce building energy consumption. Among various solutions, solar photovoltaic thermal (PVT) collectors and phase change materials (PCMs) are among the most promising methods receiving increasing attention. This paper presents a thermal performance evaluation and optimal design of buildings integrated with air-based solar PVT collectors and PCMs embedded in the building envelope by using The Hooke-Jeeves pattern search method. The Hooke-Jeeves generalized pattern search is used to search for optimal solutions of the optimization problem. The variables optimized include the PVT air flow rate, additional wall …


Breakaway Oxidation Behaviour Of Ferritic Stainless Steels At 1150 °C In Humid Air, Xiawei Cheng, Zhengyi Jiang, Brian J. Monaghan, Dongbin Wei, Raymond Longbottom, Jingwei Zhao, Jianguo Peng, Ming Luo, Li Ma, Suzhen Luo, Laizhu Jiang Jan 2016

Breakaway Oxidation Behaviour Of Ferritic Stainless Steels At 1150 °C In Humid Air, Xiawei Cheng, Zhengyi Jiang, Brian J. Monaghan, Dongbin Wei, Raymond Longbottom, Jingwei Zhao, Jianguo Peng, Ming Luo, Li Ma, Suzhen Luo, Laizhu Jiang

Faculty of Engineering and Information Sciences - Papers: Part A

The breakaway oxidation behaviour of ferritic stainless steels 430, 443 and 445 has been investigatedat 1150◦C in humid air. The oxidation kinetics exhibited significant differences among the three ferriticstainless steels. A uniform and steady growing oxide scale was developed on the 430 steel with an evensteel/oxide interface. Local breakdown of the initially protective oxide scale occurred and oxide noduleswere developed on the 443 and 445 stainless steels, resulting in irregular and rough steel/oxide inter-faces. The breakaway oxidation behaviour was significantly influenced by the microstructure and thecomposition of the oxide scale. The Mn-Cr spinel oxide formed on top of the Cr2O3scale …


Evaluating Energy Consumption Of Air Gap Membrane Distillation For Seawater Desalination At Pilot Scale Level, Hung Duong, Paul Cooper, Bart Nelemans, Tzahi Y. Cath, Long D. Nghiem Jan 2016

Evaluating Energy Consumption Of Air Gap Membrane Distillation For Seawater Desalination At Pilot Scale Level, Hung Duong, Paul Cooper, Bart Nelemans, Tzahi Y. Cath, Long D. Nghiem

Faculty of Engineering and Information Sciences - Papers: Part A

This study aimed to optimise an air gap membrane distillation (AGMD) system for seawater desalination with respect to distillate production as well as thermal and electrical energy consumption. Pilot evaluation data shows a notable influence of evaporator inlet temperature and water circulation rate on process performance. An increase in both distillate production rate and energy efficiency could be obtained by increasing the evaporator inlet temperature. On the other hand, there was a trade-off between the distillate production rate and energy efficiency when the water circulation rate varied. Increasing the water circulation rate resulted in an improvement in the distillate production …


Graphene/Pvdf Flat-Sheet Membrane For The Treatment Of Ro Brine From Coal Seam Gas Produced Water By Air Gap Membrane Distillation, Yun Chul Woo, Youngjin Kim, Wang-Geun Shim, Leonard D. Tijing, Minwei Yao, Long D. Nghiem, June-Seok Choi, Seung-Hyun Kim, Ho Kyong Shon Jan 2016

Graphene/Pvdf Flat-Sheet Membrane For The Treatment Of Ro Brine From Coal Seam Gas Produced Water By Air Gap Membrane Distillation, Yun Chul Woo, Youngjin Kim, Wang-Geun Shim, Leonard D. Tijing, Minwei Yao, Long D. Nghiem, June-Seok Choi, Seung-Hyun Kim, Ho Kyong Shon

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.


Binder-Free And Carbon-Free 3d Porous Air Electrode For Li-O2 Batteries With High Efficiency, High Capacity, And Long Life, Wenbin Luo, Xuanwen Gao, Dongqi Shi, Shulei Chou, Jiazhao Wang, Hua-Kun Liu Jan 2016

Binder-Free And Carbon-Free 3d Porous Air Electrode For Li-O2 Batteries With High Efficiency, High Capacity, And Long Life, Wenbin Luo, Xuanwen Gao, Dongqi Shi, Shulei Chou, Jiazhao Wang, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Pt-Gd alloy polycrystalline thin film is deposited on 3D nickel foam by pulsed laser deposition method serving as a whole binder/carbon-free air electrode, showing great catalytic activity enhancement as an efficient bifunctional catalyst for the oxygen reduction and evolution reactions in lithium oxygen batteries. The porous structure can facilitate rapid O2 and electrolyte diffusion, as well as forming a continuous conductive network throughout the whole energy conversion process. It shows a favorable cycle performance in the full discharge/charge model, owing to the high catalytic activity of the Pt-Gd alloy composite and 3D porous nickel foam structure. Specially, excellent cycling performance …


Toward Biodegradable Mg-Air Bioelectric Batteries Composed Of Silk Fibroin-Polypyrrole Film, Xiaoteng Jia, Caiyun Wang, Chen Zhao, Yu Ge, Gordon G. Wallace Jan 2016

Toward Biodegradable Mg-Air Bioelectric Batteries Composed Of Silk Fibroin-Polypyrrole Film, Xiaoteng Jia, Caiyun Wang, Chen Zhao, Yu Ge, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

Biodegradable active implantable devices can be used to diagnose and/or treat disease and eventually disappear without surgical removal. If an "external" energy source is required for effective operation then a biocompatible and biodegradable battery would be ideal. In this study, a partially biodegradable Mg-air bioelectric battery (biobattery) is demonstrated using a silk fibroin-polypyrrole (SF-PPy) film cathode coupled with bioresorbable Mg alloy anode in phosphate buffered saline (PBS) electrolyte. PPy is chemically coated onto one side of the silk substrate. SF-PPy film shows a conductivity of ≈1.1 S cm−1 and a mild catalytic activity toward oxygen reduction. It degrades in a …


One-Dimensional Manganese-Cobalt Oxide Nanofibres As Bi-Functional Cathode Catalysts For Rechargeable Metal-Air Batteries, Kyu-Nam Jung, Soomin Hwang, Min-Sik Park, Ki Jae Kim, Jae-Geun Kim, S X. Dou, Jung Ho Kim, Jongwon Lee Jan 2015

One-Dimensional Manganese-Cobalt Oxide Nanofibres As Bi-Functional Cathode Catalysts For Rechargeable Metal-Air Batteries, Kyu-Nam Jung, Soomin Hwang, Min-Sik Park, Ki Jae Kim, Jae-Geun Kim, S X. Dou, Jung Ho Kim, Jongwon Lee

Australian Institute for Innovative Materials - Papers

Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the …


Small Field In-Air Output Factors: The Role Of Miniphantom Design And Dosimeter Type, Kirbie Warrener, Benjamin Hug, Paul Liu, Anna Ralston, Martin A. Ebert, David Mckenzie, Natalka Suchowerska Jan 2014

Small Field In-Air Output Factors: The Role Of Miniphantom Design And Dosimeter Type, Kirbie Warrener, Benjamin Hug, Paul Liu, Anna Ralston, Martin A. Ebert, David Mckenzie, Natalka Suchowerska

Faculty of Engineering and Information Sciences - Papers: Part A

The commissioning of treatment planning systems and beam modeling requires measured input parameters. The measurement of relative output in-air, Sc is particularly difficult for small fields. The purpose of this study was to investigate the influence of miniphantom design and detector selection on measured Sc values for small fields and to validate the measurements against Monte Carlo simulations. Measurements were performed using brass caps (with sidewalls) or tops (no sidewalls) of varying heights and widths. The performance of two unshielded diodes (60012 and SFD), EBT2 radiochromic film, and a fiber optic dosimeter (FOD) were compared for fields defined by MLCs …


Biocompatible Ionic Liquid-Biopolymer Electrolyte Enabled Thin And Compact Magnesium Air Batteries, Xiaoteng Jia, Yang Yang, Caiyun Wang, Chen Zhao, R Vijayaraghavan, Douglas R. Macfarlane, Maria Forsyth, Gordon G. Wallace Jan 2014

Biocompatible Ionic Liquid-Biopolymer Electrolyte Enabled Thin And Compact Magnesium Air Batteries, Xiaoteng Jia, Yang Yang, Caiyun Wang, Chen Zhao, R Vijayaraghavan, Douglas R. Macfarlane, Maria Forsyth, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

With the surge of interest in miniaturized implanted medical devices (IMDs), implantable power sources with small dimensions and biocompatibility are in high demand. Implanted battery/supercapacitor devices are commonly packaged within a case that occupies a large volume, making miniaturization difficult. In this study, we demonstrate a polymer electrolyte-enabled biocompatible magnesium-air battery device with a total thickness of approximately 300 μm. It consists of a biocompatible polypyrrole-para(toluene sulfonic acid) cathode and a bioresorbable magnesium alloy anode. The biocompatible electrolyte used is made of choline nitrate (ionic liquid) embedded in a biopolymer, chitosan. This polymer electrolyte is mechanically robust and offers a …


Analysis Of Interference Factors Of Air Turbine Cascades, Andrei Gareev, Prabuono Buyung Kosasih, Paul Cooper Jan 2013

Analysis Of Interference Factors Of Air Turbine Cascades, Andrei Gareev, Prabuono Buyung Kosasih, Paul Cooper

Faculty of Engineering and Information Sciences - Papers: Part A

This paper reports viscous compressible aerodynamics analysis of two-dimensional cascades (arrays of aerofoils).


Distortion Behavior Of A Heavy Hydro Turbine Blade Casting During Forced Air Cooling In Normalizing Treatment Process, Hailiang Yu, Jinwu Kang, T J. Wang, J A. Ma, Y Y. Hu, Tianyou Huang, S B. Wang, Y Wu, C C. Zhang, Yan-Tao Dai, P Li Jan 2012

Distortion Behavior Of A Heavy Hydro Turbine Blade Casting During Forced Air Cooling In Normalizing Treatment Process, Hailiang Yu, Jinwu Kang, T J. Wang, J A. Ma, Y Y. Hu, Tianyou Huang, S B. Wang, Y Wu, C C. Zhang, Yan-Tao Dai, P Li

Faculty of Engineering and Information Sciences - Papers: Part A

Distortion behavior of blade castings in heat treatment process determines their geometrical accuracy, and improper control of it may result in additional repair, shape righting, or even rejection. This article presents a novel approach for discovering the distortion behavior of heavy blade castings during heat treatment process in production. Real-time measurements of distortion and temperature field of a heavy hydro turbine blade casting weighted 17 ton during forced air cooling in normalizing treatment process were carried out by using deformation measurement instruments and an infrared thermal imaging camera. The distortion processes of the typical locations of blade and the temperature …


Cfd Analysis Of The Performance Of Blade Cascades For Air Turbines In Oscillating Water Column Wave Energy Conversion Systems, Andrei Gareev, Paul Cooper, Prabuono B. Kosasih Jan 2008

Cfd Analysis Of The Performance Of Blade Cascades For Air Turbines In Oscillating Water Column Wave Energy Conversion Systems, Andrei Gareev, Paul Cooper, Prabuono B. Kosasih

Faculty of Engineering - Papers (Archive)

This paper presents the results of a detailed CFD (Computational Fluid Dynamics) analysis of the performance of blade cascades in reversing flow axial flow turbines for use as power take-off systems in Oscillating Water Column (OWC) Wave Energy Conversion (WEC) systems. In the first part of the paper a fundamental CFD analysis of the lift and drag data for various aerofoil profiles, using a number of different turbulence models, is described and quantitative comparisons are made with experimental data previously published by other researchers. The second part of the paper then describes CFD results of the performance of various rotors …


The Entrainment Of Air By Water Jet Impinging On A Free Surface, Wee King Soh, W Y Daniel Yuen, Boo Cheong Khoo Jan 2005

The Entrainment Of Air By Water Jet Impinging On A Free Surface, Wee King Soh, W Y Daniel Yuen, Boo Cheong Khoo

Faculty of Engineering - Papers (Archive)

High-speed cine and video photographs were used to capture the flow patterns of a column of water jet impinging into a pool of water. The impact results in air entrainment into water in a form of a void and there are no mixing between the water in the jet and the surrounding water. Conservation of fluid momentum shows that the rate of increase of the height of the air void depends on the drag coefficient of the jet front. By neglecting the frictional losses, the application of energy conservation yields an expression that relates the maximum height of the air …


Theoretical Modelling Of Rotary Valve Air Leakage For Pneumatic Conveying Systems, Peter W. Wypych, David B. Hastie Jan 2002

Theoretical Modelling Of Rotary Valve Air Leakage For Pneumatic Conveying Systems, Peter W. Wypych, David B. Hastie

Faculty of Engineering - Papers (Archive)

Rotary valve air leakage is an important parameter for the design and operation of many dilute- and dense-phase pneumatic conveying systems. Previous methods to estimate air leakage have been largely empirical and have been found inaccurate and/or limited in their use. This paper describes a new theoretical model that has been developed to estimate rotary valve (radial clearance) air leakage. Model predictions are compared with experimental data obtained on a rotating and stationary valve subjected to a wide range of operating pressures typical of dilute- and dense-phase systems. Knowing accurately the air leakage present for any given situation, the required …


Measurement Of Air Leakage Through Rotary Valves, David B. Hastie, Ian Frew, David M. Cook, Peter W. Wypych Jan 2001

Measurement Of Air Leakage Through Rotary Valves, David B. Hastie, Ian Frew, David M. Cook, Peter W. Wypych

Faculty of Engineering - Papers (Archive)

This paper explains the procedure used to determine the amount of air leakage expelled from two different sized drop-through rotary valves. When designing a pneumatic conveying system, rotary valve air leakage may be overlooked, believed to be only a minor factor. This is somewhat true when conveying in dilute-phase where low pressures are generated, however in dense-phase pneumatic conveying where higher pressures can be produced, rotary valve air leakage can be a high proportion of the supplied air. Knowing the air leakage present for any given situation, the total supplied air mass flowrate can be adjusted to represent the actual …


Coupled Air-Water Flow Through Fractured Sandstones, Buddhima Indraratna, P Ranjith Jan 2000

Coupled Air-Water Flow Through Fractured Sandstones, Buddhima Indraratna, P Ranjith

Faculty of Engineering - Papers (Archive)

In two-phase flow within a rock mass, where both air and water phases flow together, the accurate flow measurement of each individual phase is important in numerical analyses. The increased quantity of water phase decreases the relative permeability of the air phase, and vice versa. The relative permeability is important to analyse the risk of groundwater inundation and gas outbursts particularly in underground excavations. Two-phase flow (i.e., water and air) behaviour through naturally and artificially fractured standard rock cores is investigated using the high-pressure triaxial equipment developed by the authors. Findings of this study show that the individual flow rate …