Dissertations / Theses on the topic 'Airflow measurements'
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1
Louka, Petroula. "Measurements of airflow in an urban environment." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312298.
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Essah, Emmanuel Adu. "Modelling and measurements of airflow and ventilation within domestic pitched roofs." Thesis, Glasgow Caledonian University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517937.
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Wiggs, Giles F. S. "Airflow over Barchan dunes : field measurements, mathematical modelling and wind tunnel testing." Thesis, University College London (University of London), 1992. http://discovery.ucl.ac.uk/1317535/.
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There are few empirical measurements of velocity, shear velocity, sand transport, morphological change on the windward slopes of dunes.This thesis compares field measurements on a barchan dune in Oman with calculations using a mathematical model (FLOWSTAR) and measurements in a wind tunnel. All three techniques demonstrate similar patterns of velocity, confirming the acceleration of flow up the windward slope, deceleration between the crest and brink and significant flow deceleration upwind of and at the toe of the dune. The FLOWSTAR model is unable accurately to predict airflow at the brink and its predictions near the surface are highly susceptible to small-scale terrain irregularities. The measurements of shear velocity in the field and those predicted by the FLOWSTAR model reflect observations of previous studies including the widely reported upwind reduction in shear velocity. Such a reduction in shear velocity upwind of the dune should result in a reduction in sand transport and sand deposition. This is not observed in the field. Wind tunnel modelling using a near-surface pulse-wire probe suggests that the field and FLOWSTAR methods of shear velocity derivation are inadequate. The wind tunnel results exhibit no reduction in shear velocity upwind of or at the toe of the dune. This maintenance of upwind shear stress may be caused by concave (unstable) streamline curvature, which is not taken into account by the field and FLOWSTAR techniques. From this hypothesis, a new model of dune dynamics is developed relying on the establishment of an equilibrium between windward slope morphology, streamline curvature and streamwise acceleration.
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Garrison, Courtney Rollins. "Repeatability of Aerodynamic Measurements of Voice." Miami University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=miami1239309229.
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Holmberg, Eva. "Aerodynamic measurements of normal voice." Doctoral thesis, Stockholms universitet, Institutionen för lingvistik, 1993. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-40215.
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Vocal fold vibration results from an alternating balance between subglottal air pressure that drives the vocal folds apart and muscular, elastic, and restoring forces that draw them together. The aim of the present thesis is to present quantitative data of normal vocal function using a noninvasive method. Measurements are made on the inverse filtered airflow waveform, of estimated average trans glottal pressure and glottal airflow, and of sound pressure for productions of syllable sequences. Statistical results are used to infer mechanisms that underlie differences across ( 1 ) normal, loud, and soft voice, (2) normal, high, and low pitch, and (3) between female and male voices. Interspeaker variation in group data and intra speaker variation across repeated recordings is also investigated. The results showed no significant female-male differences in pressure, suggesting that differences in other measures were not primarily due to differences in the respiratory systems . Most glottal waveforms showed a DC flow offset, suggesting an air leakage through a posterior glottal opening. Results suggested (indirectly) that the males in comparison with the females had significantly higher vocal fold closing velocities (maximum flow declination rate), larger vocal fold oscillations (AC flow), and relatively longer closed portions of the cycle (open quotient) in normal and loud voice. In soft voice, female and male waveforms were more alike. In comparison with normal voice, both females and males produced loud voice with significantly higher values of pressure, vocal fold closing velocity, and AC flow. Soft voice was produced with significantly lower values of these measures and increased DC flow. Correlation analyses indicated that several of the airflow measures were more directly related to vocal intensity than to pitch. Interspeaker variation was large, emphasizing the importance of large subject groups to capture normal variation. Intraspeaker variation across recording sessions was less than 2 standard deviations of the group means. The results should contribute to the understanding of normal voice function, and should be useful as norms in studies of voices disorders as well.Härtill 5 uppsatser.För att köpa boken skicka en beställning till exp@ling.su.se/ To order the book send an e-mail to exp@ling.su.se
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Moat, Bengamin I. "Quantifying the effects of airflow distortion on anemometer wind speed measurements from merchant ships." Thesis, University of Southampton, 2003. https://eprints.soton.ac.uk/207/.
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Anemometers on Voluntary Observing Ships (VOS) are usually located above the bridge in a region where the effects of air flow distortion, created by the presence of the ship, may be large. Until now it was not known whether measurements from such anemometers would be biased high or low, and the possible magnitude of any such bias was not known. Investigations into the airflow above merchant ships have been carried out experimentally using a low-speed wind tunnel and numerically using a commercial Computational Fluid Dynamics (CFD) code VECTIS. The investigations examined the airflow over simple block models of VOS shapes. The results of the investigations were compared to wind speed measurements made from the RRS Charles Darwin. Experimental and CFD techniques have been used to devise scaling rules that predict the effects of the flow distortion. Both techniques have shown that the pattern of the flow distortion above the bridge scales with the ‘step height’, H, of the model. In the case of a tanker, H is the ‘bridge to deck’ height, i.e. the height of the accommodation block above the deck, for bow-on flows. Close to the top of the bridge the flow is severely decelerated and may even reverse in direction. Using the upwind edge of the bridge as the origin of the scaled co-ordinate system, there is a definite line above the decelerated region along which the speed of the flow is equal to the undistorted wind speed. Above this ‘line of equality’ the wind speed increases to a maximum and then decreases with increased height to a free stream wind speed. Simple equations have been devised to predict the positions of the ‘line of equality’, the maximum wind speed and the minimum wind speed within the decelerated region. Comparisons of the results with wind speed data obtained from field measurements made using a number of anemometers located on the RRS Charles Darwin agreed well and have predicted a maximum wind speed increase of approximately 15 ±5 %. Comparisons with the field data have confirmed that CFD models can be used to predict the effects of airflow distortion above merchant ships. The investigation has demonstrated the ability of the wind tunnel and CFD approaches employed to provide a better understanding of the airflow over merchant ships. Both methods have contributed to improve the understanding of how the wind speed at anemometer sites on merchant ships is affected by the ships hull and superstructure.
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Glover, N. "Investigating the impact of trees on airflow within street canyons through the use of CFD and field measurements." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1472912/.
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The local wind climate within the urban environment plays a key role in the removal of heat and pollutants from pedestrian occupied areas as well as having an impact on pedestrian comfort and safety. One component of the urban landscape which is often neglected in the consideration of airflow is tree planting which can constitute a major component of the built environment. The aim of this research was therefore to gain a greater understanding into the effect of tree planting on airflow within street canyons and investigate the use of CFD modelling in predicting such effects. This aim was accomplished through the use of CFD modelling and field measurements of tree-lined and non tree-lined streets. Tree canopies were represented within the CFD model by porous subdomains containing momentum and turbulence sinks. This simple representation was found to offer favourable comparison against field measurements and would therefore provide a simple and effective method for the inclusion of trees within CFD models of the urban environment. Results of both the CFD models and field measurements found reduced wind speeds at pedestrian level as well as a significant reduction in vertical wind speeds at roof level within the tree-lined street. There was also seen to be a significant reduction in turbulence levels within the street containing trees. Based on these findings it can be concluded that trees are likely to be a useful aid in urban design helping to reduce high wind speeds and turbulence thus creating outdoor environments which are comfortable and safe for pedestrian use. However the results also indicate that the addition of trees to streets can reduce the amount of air exchange at roof top level that occurs and thus may lead to a reduction in natural ventilation and potential build-up of pollutants within pedestrian occupied areas.
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Stephens, Arthur William, and arthur stephens esb ie. "Aerodynamic Cooling of Automotive Disc Brakes." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070108.121737.
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Sufficient heat dissipation is crucial to the effective operation of friction based braking systems. Such cooling is generally provided by ensuring a sufficient supply of cooling air to the heated components, hence the aerodynamics in the region of the brake components is extremely important. The objective of the research was to develop an understanding of how aerodynamics could be used to improve the cooling of automotive disc brakes. Two separate sets of wind tunnel experiments were developed. Tests were performed on a vented disc (rotor) to measure the internal flow through the vents on a rotating vented disc under various conditions, including an isolated disc in still air, the disc in still air with the wheel on, the disc in moving air with the wheel on, and an on-road simulation using a ¼ car. On vehicle tests were also performed in a wind tunnel using a purpose built brake test rig. These tests measured the thermal performance of different brake discs under various operating parameters; including constant load braking, and cooling from high temperature under various speeds, wheels and disc types. It was found that airflow through vented rotors was significantly reduced during simulated on-road driving, compared to when measured in isolation, but not particularly affected by the vehicles speed. In the situations tested, vented discs offered a 40+% improvement in cooling over an equivalent sized solid rotors. However the research indicates that the greatest benefit of vented rotors over solid will be in vehicles where air entering the wheel cavity is limited, such as low drag vehicles. It was also found that the most significant improvements in brake thermal performance could be achieved by maximising the airflow into the region of the brake components; including increasing the open area of the wheel, and increasing the vehicle velocity. Other improvements can be achieved by using a wheel material with good conductive capability, and increasing the mass of the disc. Evidence of vortex shedding was also discovered in the airflow at the exit of an internal vented rotor, any reduction in this flow disturbance should lead to increased airflow with associated improvements in thermal performance.
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Lapáček, Milan. "Čištění vzduchotechnických systémů a dosažitelné energetické úspory." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232143.
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The main aim of this thesis is to explore fouling of air ducts and its influence on energy consumption of HVAC systems. The first part focuses on typical parts that create the IAQ in buildings and on evaluating energy consumption of air transportation. The following section deals with the theories of fluid flow, flow regimes and pressure losses that are created as a side effect. The thesis outlines possible methods of assessing the impact of pollution with an emphasis on pressure losses and their influence on the fan power consumption. The actual experimental measurement, conducted in a selected industrial plant, is focused on an influence of cleanness of textile diffuser on HVAC device power consumption. For the further research of this process, measuring equipment with suitable measurement method is designed and constructed.
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Church, Sally Georgina. "On the measurement of airflow obstruction in conscious man." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309143.
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Mayes, Alex. "LDA and CFD calibrations of airflow-measurement instruments in industry." Thesis, London South Bank University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.634038.
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This study involved the use of Laser Doppler Anemometry (LDA) to measure air flows at high temporal and spatial resolution for the calibration of high-precision instrumentation, together with the use of Computational Fluid Dynamics (CFD) modelling tools. The work was performed in conjunction with BSRIA Instrument Solutions (BIS) with the main aim of improving the speed and accuracy of the calibration facilities within the BIS laboratory through the novel application of these technologies. Throughout the exploration of each facility, experimental LDA measurements, theory and virtual CFD models were compared to explore the airflow behaviour. In Part 1 of the investigation, this primarily focussed on a Balometer Calibration Facility (BCF – volume flow device) and an Open Jet Wind Tunnel (OJWT – air velocity device); both controlled using orifice plate pressure drops. The BCF was explored using attached sections of square ducting with optical access for LDA measurements. A traversing method was devised to measure volumetric flow rates, which were compared to the measured orifice plate pressure drops in order to achieve calibration of the facility. Comparing traversing methods showed that a Log-Tchebycheff method provided the most accurate prediction. The BCF calibration method was devised such that is could be applied to other volume flow facilities. These experimental measurements were compared with CFD simulations of ducted airflow in square and circular cross-section geometries for further analysis including the theoretical 1/7th power law velocity profile along with profile method comparisons. A further volume flow device, the Blower Door Calibraion Facility (BDCF) was investigated using a similar process to show the generality of the devised method. The OJWT, a facility typically used to calibrate velocity devices such as anemometers, was calibrated using a simple but novel calibration process involving LDA. To investigate further the OJWT behaviour, CFD models were created to represent OJWT with and without an anemometer and contrasted with equivalent experimental situations. A comparison of these experimental and computational data sets was performed showing representation of experimentally observed phenomena within the CFD model. This included so-called „blockage factors‟, mentioned below. iii In operation, to achieve the calibration of anemometers, the OJWT must make use of Blockage Factors (BFs) in order to correct the calibrated reference velocity to determine the actual velocity experienced by the unit under test. This was explored in Part 2 of the project. Experimental and computational (CFD) investigations were performed to explore the nature of the BFs towards a method of prediction. This would be of great use to industry as an anemometer calibration is not valid on an OJWT if an incorrect BF was applied. Outputs include: Novel methods of calibration were devised for test facilities which successfully achieved UK Accreditation Service (UKAS) certification. LDA was used to show that, in square ducts, the Log-Tchebycheff profiling method performs better than Equal Areas at providing an estimate for average cross sectional velocity when both low- and high- flow rates are considered. To verify CFD models of ducted airflow and of near-field measurements around an anemometer within an OJWT, LDA was shown to be a powerful tool. The basis for a method of BF prediction was proposed. This is based upon the empirical relationship between a statistical analysis of numerous calibrations along with an experimental LDA measurement of the deflection of air around an anemometer (Radius Expansion – RE). This is a first use within the industry and is an original contribution to knowledge. CFD models were also employed in the investigation of BFs, and the empirical relationship was applied to the data extracted from these simulations. Results closely matching the expected values were produced. The empirical relationship (between RE and BF) was demonstrated through estimation of the BF of an unknown Kimo 70 mm anemometer.
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Katurji, Marwan. "Turbulence and airflow variations in complex terrain: a modelling and field measurement approach for wind turbine siting." Thesis, University of Canterbury. Geography, 2011. http://hdl.handle.net/10092/5934.
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As the demand for global renewable energy grows, so does the demand for more
efficient energy conversion machines and better wind resource assessment. The
need to convert as much energy as possible with little cost remains the biggest
challenge. In the wind energy sector, the quantity of the resource “wind” is not
hard to locate, as with current ground and space based remote sensing
technologies, and climate reanalysis techniques, the mapping of average wind
speeds across the globe is achievable. The difficulty lies in identifying the
“quality” of the wind resource. “Quality” is the measure of the time variant
properties of the wind, and time scale here does not represent seasonal,
monthly, or the daily variability, but rather the changes within hours, minutes,
seconds, and sub‐second periods. Wind possesses a highly unpredictable, and
non‐universal character, which is referred to as turbulence. These
intermittencies in the wind speed create variable mechanical loads on the
structure of wind turbines leading to fatigue, and ultimately failure. Identifying
site specific qualities of the wind resource is very crucial in the design and
selection process of the wind turbine.
Physical theories explaining wind turbulence phenomena over flat terrain have
been critiqued and tested by observations, and in general, have achieved
reasonable success in explaining surface layer wind dynamics that can be
applied universally. This universality, and the extrapolation of flat terrain
theories to complex terrain applications, breaks down most of the time due to
the newly recognized spatial and temporal spectrum of interaction modes,
mechanically and thermodynamically, with the surrounding complex terrain.
In terrain as found in New Zealand, most of the wind farm development is
carried out over complex terrain, with ridge top and mountainous installations.
In this study, an experimental campaign was carried out over a coastal ridge top,
proposed for wind farming, to investigate mean and turbulent wind flow
features significant for wind turbine selection and placement across the ridge.
The steep sloped faces of the ridge, high wind speeds and its proximity to the sea
made this location ideal for a benchmark investigation site. Ultra‐sonic
ii
anemometers, a sodar (sound detection and ranging) wind profiler, and high
resolution LES (large eddy simulation) numerical modelling were all utilized
separately and in an interconnected way to provide a comprehensive analysis of
the wind dynamics over the ridge top. The three principal components of the
investigation were: the effect of the upstream topography and the thermal
circulation associated with the proximity to the sea on the observed and
modelled wind shear vertical profile; the role that the near upwind terrain plays
in shaping the turbulence energy spectrum and influencing the predicted
spectrum, ultimately affecting isotropy in the flow field and turbulence length
scales; turbulence advection from far topography, and the role that far upwind
terrain plays in altering the wind turbulence in a measurement area or at a single
point.
Results showed that the thermal wind circulations and upstream steep
topography could dictate the wind shear profile, and consequently have a large
impact on wind turbine height selection and placement. The sodar proved to be a
very useful tool in identifying vertical shear zones associated with effects of
steep upstream terrain, vertical mixing of horizontal momentum, and thermal
circulation from the local sea breeze.
In complex terrain, the added multi‐directional perturbations from the
underlying roughness redistribute the statistical variations (measured by
variances) in the three spatial dimensions. Isotropy, based on measured
variances, was attained for both sites on the ridge. Isotropy also held true for the
energy spectrum via Fourier analysis of the high temporal resolution data, but
not for both sites. In general, local isotropy can be attained in cases of higher
wind speeds and increased terrain relief. Measured spectral ratios did not
converge to the limit suggested by the local isotropy hypothesis. These results
identify contradictions in assessing the turbulence isotropy in both real space
(statistically through variances) and Fourier space (through power spectrum
analysis), which suggests caution in deriving or interpreting turbulence
information for wind turbine design and selection.
iii
2D‐LES experiments showed that turbulent kinetic energy (TKE) can attain long
range memory of underlying terrain, which can then react accordingly with
upcoming terrain. Under the high wind speed scenarios, which are suitable for
wind farming, and over relatively complex terrain, the flow retained some
aspects of terrain information at least 30H (H is the terrain height) upstream and
downstream of the terrain. In general, as the turbulence field travels over new
terrain it tends to increase in intensity downstream of that feature. The newly
modified TKE field acquires geometric features from the underlying terrain;
mainly these features register as amplifications in the wave structure of the field
at wavelengths comparable to the height of the underlying terrain. The 2D‐LES
sensitivity experiments identified key areas of high mean wind speed and
turbulence in relation to terrain effects, all of which should be taken into
consideration when thinking of locating a wind farm in such areas.
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Rae, Rebecca C. "Measures of Voice Onset Time: A Methodological Study." Bowling Green State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1522356095329958.
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Sandham, John Andrew. "The measurement of craniofacial morphology, head posture and nasal airflow in patients with congenital clefts of the lip and palate." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/26916.
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The present study was both methodological and investigative in nature. This included the development of computerised rhinomanometry and establishment of cephalometric measurement apparatus together with a standardised lateral cephalometric radiography technique to record natural head posture. The method errors of both the measurement systems and the operator were tested by duplicate determinations and subsequent statistical analysis. Recordings for all the variables in the study were reproducible without systematic error and with a very small method error. Apparatus was used to record nasal respiratory resistance (NRR), craniofacial form and head posture in a control group for comparison with subjects with cleft lip (CL), cleft palate (CP), and unilateral cleft lip and palate (UCLP). The results of the rhinomanometric recording indicated that the bilateral nasal resistance did not differ significantly between the cleft samples and the controls. Unilateral measurements of nasal resistance showed higher values for the cleft side than for the non-cleft side, both in cleft lip (CL) and the unilateral cleft lip and palate (UCLP) samples. In the cleft palate (CP) sample as well as in the controls, unilateral nasal resistance did not differ between the two sides. Comparisons were made between cephalometric measurements for craniofacial form and head posture for each category of the clefting deformity and the controls and the statistically significant differences tabulated. Previous studies have demonstrated associations between cranio-cervical angulation and craniofacial morphology, and between airway adequacy and cranio-cervical angulation. In the present study, differences and correlations were calculated between face height, head posture and airway resistance which were in agreement with the predicted pattern of associations between cranio-cervical angulation and craniofacial morphology (face height) and between airway adequacy and cranio-cervical angulation.
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Slováček, Antonín. "Měření průtoku plynů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219868.
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The diploma thesis brings a description and realization of new measuring devices which are designed to support student´s laboratory practice of air flow measurement techniques. The new devices and laboratory exercises help students get experience of several methods of measuring which they get to know during mandatory Bachelor's and Master's study programmes. The paper also includes a theoretical background, the knowledge of which is necessary for mastering the issue. Moreover, the paper comprises a literary search of sensors and a market research. The second part of the thesis presents possibilities of the laboratory workplace, and the results of the measurements of the new laboratory devices used for sample laboratory exercises.
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Rydberg, Adam, and Alexandra Lindesvik. "Analys och ekonomisk utvärdering av två metoder för att lufttäta flerbostadshus." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Byggnadsteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-36933.
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Syfte: Syftet är att genom en strukturell jämförelse av fallstudiens undersökningsobjekt få en överblick över kostnaden för arbetsutförandet av två luttätnings- och provtryckningsmetoder. Detta för att ta fram vilken metod som är lämpligast att tillämpa med avseende på kostnad. Metod: Metoderna som tillämpats för att besvara målet var observationer, mätningar, beräkningar, litteraturstudie samt intervjuer. Den huvudsakliga metoden som användes var observationstekniken ”observatör som deltagare”. Intervjuer tillämpades för att anbringa ny kunskap men även verifiera empirin hämtad från observationerna. Resultat: Studien visar att det finns både mindre och markanta skillnader mellan objektens lufttätnings- och provtryckningsmetoder som genererar både för och nackdelar. De största skillnaderna var framförallt vid fönster- och dörrutförandet, materialvalet i installationsväggen och om en tidig provtryckning utförs eller inte. Fördelarna med Gripen var att de inte var beroende av utomstående aktörers utförande vid fönsteranslutningen samt att de hade ett moment mindre under kontrollen av klimatskalet. Studien visar även att Gripen hade en lägre totalkostnad för lufttäthetsarbetet än Vimans Trädgård. Dock var kostnaden per kvadratmeter desto högre för varje färdigställd kvadratmeter. Efter en noggrann strukturell jämförelse bedömdes Vimans Trädgårds tillvägagångssätt var den mest kostnadseffektiva lufttätnings- och provtryckningsmetoden utifrån kr/kvm, se Tabell 13. Konsekvenser: Studien visar att båda objektens metoder fungerar för att nå byggnadens ställda lufttäthetkrav. Då metoderna liknade varandra på många punkter kunde slutsatsen dras att lufttätningsutförandet av fönster- och dörranslutningar hade en stor inverkan på tiden samt kostnaden. Slutligen kan följande rekommendationer ges, en byggnads lufttäthet bör säkerställas i ett tidigt skede, företagens luftätningsmetoder bör fortsätta utvecklas samt en enhetlig lufttätnings- och provtryckningsmetod bör utformas och appliceras inom hela företaget. Begränsningar: Rapportens undersökningsstrategi är en kvantitativ fallstudie. Studien begränsas till fallstudiens båda undersökningsobjekt och deras lufttätnings- samt provtryckningsmetod utan avseende till materialkostnader. Undersökningen begränsas även till objektens förutsättningar som materialval men tar ingen hänsyn till geografisk placering eller väderstrecksorientering. Detta medför att studien är giltig under specifika förhållanden. Vid en eventuell upprepning kan studien påvisa andra resultat och generera skilda slutsatser än det som vidtagits i denna utredning.Purpose: The purpose is to provide an overview of the cost of the work performance of two air tightening and pressure testing methods through a structural comparison of the case study's investigative objects. This is to find out which method is most appropriate to apply in terms of cost. Method: The chosen methods, used to answer the goal, were observations, measurements, calculations, literature studies and interviews. The main method used was the observation technique "observer as a participant". Interviews were applied to conceive new knowledge, but also to verify the information from the observations. Findings: The study shows that there are both minor and significant differences between the objects air tightening and pressure testing methods that generate both pros and cons. The main differences were mainly the execution of the windows and doors, the choice of materials in the installation wall and if an early pressure test is performed or not. The benefits of Gripen were that they were not dependent on external operator’s performance at the window connection and that they had a moment less under the control of the climate scale. The study also shows that Gripen had a lower total cost of air tightness than Vimans Trädgård. However, the cost per square meter was the higher for each completed square meter. After a careful structural comparison, Vimans Trädgård ́s approach was evaluated as the most cost-effective air tightening and pressure testing method, see Table 13. Implications: The study shows that the air tightening methods of both objects work to reach the building's airtightness requirements. As the methods were similar at many points, it could be concluded that the air tightening of window- and door connections had a major impact on time as well as the cost. Finally, the following recommendations that can be given is, building airtightness should be ensured at an early stage, companies' air tightening and pressure testing methods should continue to evolve and a uniform air tightening and pressure testing method should be designed and applied throughout the companies. Limitations: The report's investigation strategy is a quantitative case study. The study is limited to two study objects of the case study and their air tightening and pressure testing method without regard to material costs. The investigation is also limited to the object's conditions as material choice, but does not consider geographical location or weather-orientation. This means that the study is valid under specific conditions. In the event of a repeat, the study can demonstrate other results and generate different conclusions than those undertaken in this investigation.
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Chen, Austin Miguel. "Couplage entre ventilation naturelle et stockage-déstockage d'énergie sensible en bâtiment : approche expérimentale et modélisation." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0150/document.
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Dans le cadre de la recherche de solutions visant à réduire les consommations d’énergie liées au rafraîchissement des bâtiments, une plateforme d’essais a été mise en place en 2012 à l’I2M et installée sur le site de l’IUT de l’Université de Bordeaux. Cette plateforme est issue d’un prototype de bâtiment BEPos, dénommée Sumbiosi, réalisée par un consortium rassemblé autour du campus de Bordeaux dans le cadre de sa participation à la compétition interuniversitaire du Solar Decathlon Europe 2012. Elle a notamment été conçue de façon à favoriser le stockage passif d’énergie diurne en hiver et le déstockage semi-passif d’énergie nocturne en été. Deux éléments principaux permettent a priori ces fonctions de stockage et déstockage passifs d’énergie : une dalle de forte masse thermique située du côté de la façade Sud vitrée du bâtiment, et des protections solaires et ouvertures pilotables sur les façades Sud, Nord et en lanterneau du bâtiment ; ces dernières assurent les trois principes fondamentaux en ventilation naturelle qui ont lieu grâce aux effets du tirage thermique et de la force du vent. L’objet des travaux menés actuellement ont pour objectif initial d’appréhender qualitativement le stockage-déstockage d’énergie dans la dalle, celle-ci étant soumise à des échanges radiatifs (extérieur et d’intérieur) et convectifs (générés par convection naturelle, forcée ou mixte). Ils visent par la suite à caractériser précisément et quantitativement le couplage entre ce stockage-déstockage, et les circulations d’air et apports radiatifs constatés. La mise en place d’une modélisation, reliant l’ensemble de ces paramètres est envisagée, dans le but d’avancer vers une loi de pilotage de ces éléments mobiles amenant à des conditions de confort internes au bâtiment optimales. Cette dernière doit nous permettre de montrer qu’un choix adéquat de stratégie de ventilation permet une minimisation de consommations électrique en évitant autant que possible le recours à la climatisation. Pour atteindre cet objectif, la démarche scientifique adoptée a consisté à mettre en évidence le rôle de la dalle en béton dans stockage/déstockage d’énergie thermique, sous l’effet de différents scénarii de ventilation naturelle de la plateforme. Cette dalle a été instrumentée, de façon discrète sur l’ensemble de sa surface, en termes de capteurs de flux de chaleur (Peltier et Captec), de températures (thermocouples T), et de la vitesse d’air proche de la dalle. Les premiers résultats, obtenus en période estivale, mettent clairement en évidence le couplage entre les phénomènes de stockage et déstockage d’énergie quotidiens et le cycle météorologique correspondant, ceci pour divers scénarii de pilotage des éléments mobiles de l’enveloppe du bâtiment (persiennes, ouvertures)As part of the search for solutions to reduce the energy consumption related to the refreshment of buildings, a test platform was set up in 2012 at the I2M and installed on the IUT site of the " University of Bordeaux. This platform is the result of a prototype of a PEHs building called Sumbiosi, carried out by a consortium gathered around the Bordeaux campus as part of its participation in the inter-university competition of the Solar Decathlon Europe 2012. It was conceived in such a way as to favor the passive storage of diurnal energy in winter and the semi-passive destocking of nighttime energy in summer. Two main elements allow a priori these functions of passive storage and retrieval of energy: a slab of high thermal mass located on the side of the glazed south facade of the building, and solar protections and openings controllable on the facades South, North and skylight of the building ; the latter provide the three fundamental principles of natural ventilation, which take place through the effects of thermal draft and wind force. The object of the work currently carried out has the initial objective of qualitatively understanding the storage and de-stocking of energy in the slab, the latter being subjected to radiative (external and internal) and convective exchanges (generated by natural convection, forced or mixed). They are intended to characterize precisely and quantitatively the coupling between this storage and release, and the circulations of air and radiative contributions observed. The implementation of a modeling, linking all these parameters is envisaged, with the aim of advancing towards a law controlling these mobile elements leading to optimum internal comfort conditions for building. The latter must enable us to show that an adequate choice of ventilation strategy allows a minimization of electrical consumption by avoiding the use of air conditioning as much as possible. To achieve this objective, the scientific approach adopted consisted in highlighting the role of the concrete slab in the storage / destocking of thermal energy, under the effect of different scenarios of natural ventilation of the platform. This slab was instrumented, discretely over its entire surface, in terms of heat flux sensors (Peltier and Captec), temperatures (T thermocouples), and air speed close to the slab. The first results, obtained during the summer period, clearly show the coupling between the phenomena of daily energy storage and destocking and the corresponding meteorological cycle for various scenarios controlling the moving elements of the building envelope (shutters, openings)
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Fu, Sijie. "Vélocimétrie par suivi 3D de particules pour la caractérisation des champs thermo-convectifs dans le bâtiment." Thesis, Université Côte d'Azur (ComUE), 2016. http://www.theses.fr/2016AZUR4078/document.
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L'objectif de cette thèse est de réaliser une étude approfondie sur la vélocimétrie par suivi 3D de particules (3D Particle Tracking Velocimetry, 3D PTV) pour l'air intérieur convective thermique. Ce travail se concentre principalement sur l'étude de la littérature, l'évaluation des performances des algorithmes de mesure de la 3D PTV, et l'étude expérimentale pour l'air intérieur convective thermique en utilisant la technologie 3D PTV. Tout d'abord, la technologie 3D PTV typique et ses principales applications précédentes pour l'étude de d'air intérieur sont examinés. Ensuite, les performances de différents algorithmes de mesure de la 3D PTV sont évalués numériquement et expérimentalement. Deux sections se compose de cette partie, on est de comparer les performances de mesure de l'algorithme de PIV typique et l'algorithme de 3D PTV, une autre est de comparer les performances des sept algorithmes complets de 3D PTV. Enfin, sur la base de l'analyse présentée dans la thèse, l'étude expérimentale de l'écoulement d'air intérieur généré par la méthode de ventilation mélange est réaliséeThe objective of this thesis is to conduct a comprehensive study on 3D Particle Tracking velocimetry (PTV) for thermal convective indoor airflow. This work mainly concentrates on the literature survey, the performance evaluation of 3D PTV measurement algorithms, and the experimental investigation for thermal convective indoor airflow using 3D PTV measurement technology. First, typical 3D PTV technology and its main previous applications for indoor airflow study are carefully reviewed. Then, the performances of different 3D PTV measurement algorithms are evaluated numerically and experimentally. Two sections consist of this part, one is to compare the measurement performances of typical PIV algorithm and 3D PTV algorithm, another is to compare the performances of seven complete 3D PTV algorithms. Last, based on the analysis in the thesis, the experimental investigation for indoor airflow generated by mixing ventilation method is conducted
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Huang, Fu-Chia, and 黃富加. "Measurements Airflow and Analysis Factors Influencing Airflow in Unidirectional Flow Pilot Scale Clean Room." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/56872895282821386054.
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碩士國立交通大學
機械工程系
91
The requirement of high quality clean environmet in many aspects of important sciences and technology has rapidly gained momentum in the last ten years. Meanwhile, energy problems had also become worldwide profound issues. Therefore, the issues about how to promote cleanliness and retrench energy are important. The objective of this research is to study airflow characteristics in class 10 FFU clean room by both experiment measurement and numerical calculation. The STAR-CD commercial CFD software had been adopted for the numerical calculation. First, airflow characteristics in clean room are identified by investigated different grating floor open ratios, areas near the bench and inlet velocity of the side FFUs. Second, we try to proof CFD fits the results of measuring airflow in an empty pilot scale clean room. The measurements of the three components of air velocity were conducted by means of a three dimensional ultrasonic anemometer. The results show that the grating floor open ratio near bench in 30 cm and the area of 50% grating floor open ratio can’t improve the airflow turbulent intensity near the bench. Besides, a very good fit between data of measurements and outcome of simulation was found. It is envisaged that the results of the numerical simulation is a useful device for the design of full scale clean room.
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Sun, Yigang. "Volumetric Particle Streak-Tracking Velocimetry and its application in indoor airflow measurements /." 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3270038.
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Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.Source: Dissertation Abstracts International, Volume: 68-06, Section: B, page: 3928. Adviser: Yuanhui Zhang. Includes bibliographical references (leaves 132-146) Available on microfilm from Pro Quest Information and Learning.
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Elyyan, Mohammad. "Design of an experimental facility for building airflow and heat transfer measurements." 2005. http://digital.library.okstate.edu/etd/umi-okstate-1316.pdf.
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Karava, Panagiota. "Airflow prediction in buildings for natural ventilation design : wind tunnel measurements and simulation." Thesis, 2008. http://spectrum.library.concordia.ca/975816/1/NR37740.pdf.
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Natural/hybrid ventilation systems with motorized operable windows, designed and controlled to utilize the potential for cross-ventilation, represent an area of significant interest in sustainable building design as they can substantially reduce energy consumption for cooling and ventilation. Presently, there is a need for accurate prediction models that can contribute to the improvement of indoor environmental quality and energy performance of buildings, and the increased use of low energy, naturally driven cooling systems. In this regard, the present research aims to enhance airflow prediction accuracy for natural ventilation design of buildings considering advanced experimental and simulation methods. The study considers a Boundary Layer Wind Tunnel (BLWT) approach to investigate the wind-induced driving forces and ventilation flow rates in various building models subject to cross-ventilation. The Particle Image Velocimetry (PIV) technique was used for the first time to evaluate accurately the air velocity field for various cross-ventilation configurations. Detailed measurements were performed to determine mean and fluctuating internal pressures since they affect airflow prediction, occupants' thermal comfort, as well as cladding and structural wind load design of buildings with operable windows. PIV data for the inflow velocity were compared with those by using conventional techniques (e.g., hot-film anemometry) and results show differences, between the two methods, up to a factor of 2.7. This clearly indicates that accuracy can be enhanced with carefully conducted PIV experiments. The study provides guidelines for implementation of cross-ventilation in design practice. These guidelines were developed on the basis of parametric experimental investigations, which quantify the impact of relative inlet-to-outlet size and location on ventilation airflow rates and thermal comfort of building occupants. The study develops a novel simulation methodology combined with a sensitivity analysis focused on modelling issues, such as the impact of zoning assumptions, to predict the envelope pressures and related air-exchange rates in buildings due to wind, stack, and mechanical system effects. An integrated simulation tool (ESP-r) was used to model the airflow/energy interactions in an existing high-rise residential building, and simulation results agree well with monitoring data.
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Wang, Yu-Hsiang, and 王禹翔. "Micro Cantilever-Based Flow Meter for High Airflow Velocity Measurement." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/24560890219622203053.
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碩士大葉大學
機電自動化研究所碩士班
94
This paper exploits a bending-up cantilever caused by residual stress to manufacture a micro gas flow sensor. Micro sensors not only have a smaller physical size than their traditional counterparts, but also provide a greater measurement accuracy and a higher sensitivity. In this study, mems techniques are used to deposit a silicon nitride layer on a silicon wafer to create a piezoresistive structure. A platinum layer is deposited on the silicon nitride layer to form a resistor and the structure is then etched to form a freestanding micro-cantilever. It is found that the cantilever bends upward slightly as a result of the released residual stress induced in the beam during the fabrication process. When an airflow passes over the cantilever beam, a small deformation occurs. Variations in the airflow velocity can therefore be determined by measuring the change in resistance caused by the beam deflection using an LCR meter. e experimental data indicate that the proposed gas flow meter has a high sensitivity (0.0533 Ω/ms-1), a high measurement limit (44.47 ms-1) and a rapid response time.
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Kao, Chien-Wen, and 高健文. "Numerical simulation and field measurement of airflow distribution for operation rooms." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/58519693555031097151.
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碩士國立勤益科技大學
冷凍空調系
102
Operation rooms are the most critical environment in the hospital buildings. Due to not only for indoor environment control but also for infection concern. This study investigate the indoor environment including pressurization, temperature, humidity, air change rate and particle counts of operation rooms in a district hospital, through field measurement and numerical simulation. Field measurement was conducted to evaluate the performance of the retrofitting project of the operation rooms. The results revealed that the retrofitted HVAC system for the operation rooms could improve the pressurization control performance during door opening duration, thus reducing the infection risk obviously. Furthermore, the airflow blocked by the medical devices and apparatus was also conducted via CFD simulation. Different improvement strategies to reduce contamination control were proposed including the change of height of return grille and the airflow angles of air curtain around the HEPA filter above the surgery table. The results revealed that the height of return air grille at 40 cm could improve the stagnation of contamination effectively in the non-critical area. The inclined angles of 45° around air curtain improved the air flow distribution obviously, which resulted in better performance for contamination control in the operation rooms.
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Liu, Zhao Ren, and 劉兆仁. "Measurement and simulation of airflow patterns in a prefabricated cold store." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/09247984830769918709.
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Ching, Han-Hsi, and 青含璽. "Measurement and Simulation of Airflow Pattern in a Prefabricated Center-Ceiling Evaporator." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/14172073930053152429.
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碩士國立臺灣大學
農業機械工程學系
84
Cold stores play an important part in food preservation; It is very important to understand the factors which affect the quality of products in cold stores. From literatures,the flow pattern of flow field will directly influence the temperature distribution in cold stores , and ill temperature distribution is the main factor that will cause damage to products in the cold stores. In the study,both experimental and numerical approaches were adopted to analyze the airflow characters in the prefabricated cold store. In the experimental approach , three dimensional ultrasonic anemometer was used to measure the turbulent characters in the flow field , T-type thermal-couples to obtain the temperature distribution;In simulative approach ,the FLOW-3D software and experimental consequences were used to simulate the prefabricated cold store. Moreover, the airflow characters could be improved or predicted under different loading conditions.
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Booy, Michael Philip. "Measurement and prediction of the airflow caused by free convection in stored grain." 1985. http://hdl.handle.net/1993/29138.
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Du, Hsin-Tai, and 杜興泰. "Measurement and Analysis of Airflow Patterns in a Forced-air Cooler for Leafy Vegetables." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/80598818366621952735.
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碩士國立臺灣大學
農業機械工程學系研究所
88
Forced-air cooling is one of the most effective methods of vegetable pre-cooling, especially. In Taiwan, many produce distributions gradually adopt it. However, due to the lack of primary experimental data necessary to the design, the equipment they used is still immature and not well-designed. This research endeavors to analyze the current vegetable forced-air cooling system by experiments and computer simulation. In order to explore how forced ventilation flow is influenced by air channel of vegetable cartons and fans chamber, the research measures the turbulence characteristics of airflow by the three dimensional ultrasonic anemometer. Moreover, PHOENICS computer package modeling helps establish the data of pressure and flow fields in the system. The research offers the foundation of designing vegetable forced-air cooling equipment in the near future.