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Characterization of air inlets for heavy vehicle applicationsMuller, Mark Helgaard 25 September 2014 (has links)
M.Sc. (Mechanical Engineering) / Please refer to full text to view abstract
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Measurement of air flow at vacuum conditions using small VenturisAlonso, Hector January 1980 (has links)
Small Venturis were used to measure air flow rates through cigarette-making machines to a vacuum header.
A programmable calculator was used to develop charts for each Venturi. showing flow versus differential pressure at inlet vacuums from 8 in. (203 mm) to 20 in. (508 mm) of mercury. Use of the charts eliminates the need to calculate the flow each time a test is run.
An error analysis indicated that large variations in temperature do not affect the result. The accuracy of the charts is not affected as long as the tests are run at room temperature.
The Venturis, ranging in size from ½ in. (13 mm) to l ½ in. (38 mm) will continue to be used to measure and monitor vacuum requirements of the machines. / Master of Engineering
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Mean flow measurements of heated supersonic slot injection into a high Reynolds number supersonic streamSmith, Benjamin Robert January 1989 (has links)
Mean flow measurements and short-duration Schlieren and Shadowgraph photographs of heated and unheated supersonic slot injection of air into a supersonic air stream are presented for the purpose of observing the mixing which occurs in the resulting shear layer. The heated injected jet (M<sub>j</sub>, P<sub>tj</sub> = 10.7 psia, and T<sub>tj</sub> = 760°R) passes through a slot of height 0.475 inches (1.2 cm) tangent to a free stream with M<sub>∞</sub> = 3.0, P<sub>∞</sub>= 95 psia and T<sub>t</sub><sub>∞</sub> = 540°R. The resulting density ratio is P<sub>j</sub> / P<sub>∞</sub> = 0.3. The free stream Re/ft = 6.1 x 10⁷ (Re/cm = 2 x 10⁶). The thickness of the plate which separates the primary and secondary flows is 0.021 inches (0.052 cm). Pitot pressure, cone static pressure and stagnation temperature profiles are obtained at four axial stations downstream of the slot (x/H = 0.25, 4, 10, 20). An additional set of measurements is obtained at Station 4 for the case of a weak shock (P₂/P₁ = 1.8) interacting with the shear layer just upstream of Station 4. From the pressure and temperature measurements, Mach number, velocity, density, mass flux and static pressure profiles are generated. An unheated injection study is also performed at the same flow conditions for comparison to the heated case. The heated and unheated cases are very similar except in the slot where the temperature difference creates changes inp, U, and pU. This study is thus concerned with the effects of changes in P<sub>j</sub> / P<sub>∞</sub> and U<sub>j</sub> / U<sub>∞</sub>, especially (U<sub>j</sub> - U<sub>∞</sub>), which are created by heating the injected flow. The heated slot flow did not create a marked difference in the location of the merging of the free stream boundary layer with the slot flow when compared to the unheated slot flow. Indeed, the appearance of the two flows on Schlieren photographs is similar even though the injected mass flow in the heated case is about 15% less than that in the unheated case. The pressure adjustments in the slot lip region are different for the two different cases. The flowfields are documented for both the heated and unheated cases with the added measurements and photographs for the shock impingement case. / Master of Science
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The construction of a wind tunnel and the prosecution of certain problems of research connected with itLybrook, Robert Custis, Price, William David January 1931 (has links)
M.S.
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The construction of a wind tunnel and the prosecution of certain problems of research connected with itJanuary 1931 (has links)
M.S.
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A study of the use of statistical turbulence parameters in correlating axial dispersion data in the central core of air flowing in a pipe.Exall, Douglas Ian. January 1970 (has links)
The longitudinal fluctuations at a point in the core of air flowing through a 15 cm. diameter pipe at a mean
centerline velocity of 13.4 and 29.5 m/sec. were measured with a hot-wire anemometer. This signal, after analog to
digital conversion, was stored in the form of digital samples on an ICT computer drum storage device. This method of data recording includes the effect of all eddy frequencies from DC upwards and the presence of large, slow eddies in the longitudinal direction became apparent in the subsequent autocorrelations. The longitudinal dispersion of a tracer material injected on the axis of the pipe was measured over short distances with pulses of approx. 20 msecs. duration of radioactive Krypton-85, detected at two downstream stations by small surface-barrier radiation detectors. By varying the separation of these two stations, an asymptotic mixing coefficient was established which was very much greater than the corresponding transverse mixing coefficient measured by other workers. The method proposed by Philip (4) for the prediction of the Lagrangian time autocorrelation from the Eulerian velocity measurements was examined with the correlation data of Baldwin and the data obtained in this investigation. The method applied to the unfiltered correlation data in the present measurements in a non-isotropic field to predict a longitudinal turbulent Peclet no. was found to predict a value in the region measured experimentally. When the present velocity data was
filtered to remove the low-frequency components and give a turbulence intensity equal to that measured in a radial
direction in previous dispersion measurements, the mixing coefficient predicted with Philip's method was found to agree very well with the transverse mixing coefficient reported in these investigations. A value is also suggested for the
longitudinal Peclet number in the absence of the low frequency fluctuations. / Thesis (Ph.D.)-University of Natal, Durban, 1970.
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Pneumatic power measurement of an oscillating water column converterKooverji, Bavesh 04 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: A measurement device was developed to accurately determine the pneumatic
power performance of an Oscillating Water Column (OWC) model in a wave
flume. The analysis of the pneumatic power is significant due to the wave-topneumatic
energy being the primary energy conversion process and where the
most energy losses can be expected. The aim of the research study is to address
the accurate pneumatic power measurement of unsteady and bidirectional airflow
in OWC model experiments.
The two fundamental measurements required for the pneumatic power
measurement are the pressure difference over an orifice on the OWC model and
the volumetric flow rate of air through the outlet. The designed, constructed and
assembled measurement device comprised of a venturi flow meter, containing a
hot-film anemometer, which could measure the pressure drop and the volumetric
flow rate in one device. The assembled pneumatic power measurement device
was calibrated in a vertical wind tunnel at steady state. The results from the
calibration tests showed that the volumetric flow rate measurements from the
pneumatic power measurement device was accurate to within 3 % of the wind
tunnel’s readings. The pneumatic power measurement device was incorporated
onto a constructed Perspex physical model of a simple OWC device. This
assembled system was used as the test unit in the wave flume at Stellenbosch
University (SUN).
The results from the experimental tests underwent comparative analysis with
three analytical OWC air-flow models which were simulated as three scenarios
using Matlab Simulink. These results showed that the measurement device has the
ability to measure the pneumatic power but there is difficulty in modelling the
complex air-flow system of the OWC device. This results in varying levels of
agreement between the experimental and simulated pneumatic power results. The research study has revealed that there is difficulty in designing an accurate
device for a wide range of test parameters due to the variance in output values.
The unsteady and bidirectional nature of the air flow is also difficult to accurately
simulate using a one-dimensional analytical model. Recommendations for further
investigation are for CFD systems to be used for the analysis of the air-flow in an
OWC system and to be used to validate future pneumatic power measurement
devices. / AFRIKAANSE OPSOMMING: ‘n Meetinstrument was ontwikkel om die pneumatiese kraglewering van ‘n model
van die Ossillerende Water Kolom (OWK) golfenergie omsetter in ‘n golf tenk
akkuraat te meet. Dit is belangrik om die omskakeling van golf na pneumatiese
energie te analiseer siende dat die grootste energieverlies in dié proses plaasvind.
Die doel van hierdie navorsingsprojek was om die akkurate pneumatiese
kragmeting van variërende en twee-rigting vloei van lug in ‘n OWK model na te
vors.
Die twee fundamentele metings wat benodig word vir die pneumatiese
kragbepaling is die drukverskil oor die vloei vernouing en die volumetriese
vloeitempo van lug deur die uitlaat van die toetstoestel. Die spesiaal ontwerpte
meettoestel wat gebruik is in die eksperiment het bestaan uit ‘n venturi vloeimeter
wat ‘n verhitte-film anemometer bevat het wat die drukverandering en die
volumetriese vloeitempo kan meet in ‘n enkele instrument. Die pneumatiese
kragmeting was gekalibreer in ‘n vertikale windtonnel waarin ‘n konstante vloei
tempo geïnduseer was. Die kalibrasieproses het bevestig dat die meettoestel
metings lewer met ‘n fout van minder as 3 % wanneer dit vergelyk word met die
bekende konstante vloei tempo soos bepaal in die windtonnel. ‘n Fisiese model
van ‘n vereenvoudigde OWK golfenergie omsetter was ontwerp en gebou uit
Perspex om as toetstoestel te gebruik vir die evaluering van die ontwerpte
pneumatiese kraglewering meettoestel. Die toetse was uitgevoer in ‘n golftenk by
die Universiteit Stellenbosch (SUN).
The toetsresultate was vergelyk met drie ander OWK lugvloei modelle wat
gesimuleer was deur om die analitiese modelle op te stel en te simuleer in Matlab
Simulink. Die vergelyking van modellering resultate het gewys dat die meettoestel
die vermoë het om pneumatiese krag te meet. Daar was wel komplikasies met die
modellering van die komplekse lugvloei in die OWK toestel, die resultate het geen
definitiewe ooreenstemming gewys tussen die eksperimentele en gesimuleerde
pneumatiese krag resultate nie. Die navorsingsprojek het gewys dat daar komplikasies is om ‘n enkel toestel te
ontwerp wat oor ‘n wye bereik kan meet weens die variasie van die verskillende
parameters. Die variërende en twee-rigting lugvloei is ook moeilik om akkuraat te
simuleer met ‘n een-dimensionele analitiese simulasie model. Aanbevelings vir
verdere navorsing sluit in om die lugvloei in die OWK stelsel te modelleer en te
analiseer in ‘n drie-dimensionele model om die lesings van ‘n pneumatiese krag
meettoestel te bevestig.
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Měřící systém pro sledování efektivity fotovoltaického panelu / Measuring system of photovoltaic panels efficiencyHofman, Jiří January 2010 (has links)
This diploma thesis is focused on development and initial run of a measurement system whose aim is to measure photovoltaic panel efficiency. Experimental photovoltaic panel is installed outside the laboratory. Measurement system consists of the solar radiation measurement module (pyranometer), photovoltaic panel load module (panel power measurement) and panel climate measurement module. Data from measurement module is being captured via control computer for subsequent analysis of panel efficiency and climatic impacts on it.
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