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  • 1.
    Laurantzon, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Flow measurements related to gas exchange applications2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis deals with flow measuring techniques applied to steady and pulsating gas flows relevant to gas exchange systems for internal combustion engines. Gas flows in such environments are complex, i.e. they are inhomogeneous, three-dimensional, unsteady, non-isothermal and exhibit significant density changes. While a variety of flow metering devices are available and have been devised for such flow conditions, the performance of these flow metersis to a large extent undocumented when a strongly pulsatile motion is superposed on the already complex flow field. Nonetheless, gas flow meters are commonly applied in such environments, e.g. in the measurement of the air flow to the engine or the amount of exhaust gas recirculation. The aim of the present thesis is therefore to understand and assess, and if possible to improve the performance of various flow meters under highly pulsatile conditions as well as demonstrating the use of a new type of flow meter for measurements of the pulsating mass flow upstream and downstream the turbine of a turbocharger.

    The thesis can be subdivided into three parts. The first one assesses the flow quality of a newly developed flow rig, designed for measurements of steady and pulsating air flow at flow rates and pulse frequencies typically found in the gas exchange system of cars and smaller trucks. Flow rates and pulsation frequencies achieved and measured range up to about 200 g/s and 80 Hz, respectively. The time-resolved mass flux and stagnation temperature under both steady and pulsating conditions were characterized by means of a combined hot/cold-wire probe which is part of a newly developed automated measurement module. This rig and measurement module were used to create a unique data base with well-defined boundary conditions to be used for the validation of numerical simulations, but in particular, to assess the performance of various flow meters.

    In the second part a novel vortex flow meter that can measure the timedependent flow rate using wavelet analysis has been invented, verified and extensively tested under various industrially relevant conditions. The newly developed technique was used to provide unique turbine maps under pulsatile conditions through time-resolved and simultaneous measurements of mass flow, temperature and pressure upstream and downstream the turbine. Results confirm that the quasi-steady assumption is invalid for the turbine considered as a whole.

    In the third and last part of the thesis, two basic fundamental questions that arose during the course of hot/cold-wire measurements in the aforementioned high speed flows have been addressed, namely to assess which temperature a cold-wire measures or to which a hot-wire is exposed to in high speed flows as well as whether the hot-wire measures the product of velocity and density or total density. Hot/cold-wire measurements in a nozzle have been performed to test various hypothesis and results show that the recovery temperature as well as the product of velocity and stagnation density are measured.

    Fulltekst (pdf)
    fulltext
  • 2.
    Laurantzon, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Flow Measuring Techniques in Steady and Pulsating Compressible Flows2010Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis deals with flow measuring techniques applied on steady and pulsatingflows. Specifically, it is focused on gas flows where density changes canbe significant, i.e. compressible flows. In such flows only the mass flow ratehas a significance and not the volume flow rate since the latter depends onthe pressure. The motivation for the present study is found in the use of flowmeters for various purposes in the gas exchange system for internal combustionengines. Applications can be found for instance regarding measurements of airflow to the engine, or measurements of the amount of exhaust gas recirculation.However the scope of thesis is wider than this, since the thesis aims toinvestigate the response of flow meters to pulsating flows. The study is mainlyexperimental, but it also includes an introduction and discussion of several inindustry, common flow measuring techniques.The flow meters were studied using a newly developed flow rig, designedfor measurement of steady and pulsating air flow of mass flow rates and pulsefrequencies typically found in the gas exchange system of cars and smallertrucks. Flow rates are up to about 200 g/s and pulsation frequencies from 0 Hz(i.e. steady flow) up to 80 Hz. The study included the following flow meters:hot-film mass flow meter, venturi flowmeter, Pitot tube, vortex flowmeter andturbine flowmeter. The performance of these meters were evaluated at bothsteady and pulsating conditions. Furthermore, the flow under both steady andpulsating conditions were characterized by means of a resistance-wire basedmass flow meter, with the ability to perform time resolved measurements ofboth the mass flux ρu, and the stagnation temperature T0.Experiments shows that, for certain flow meters, a quasi-steady assumptionis fairly well justified at pulsating flow conditions. This means that thefundamental equations describing the steady flow, for each instant of time,is applicable also in the pulsating flow. In the set-up, back-flow occurred atcertain pulse frequencies, which can result in highly inaccurate output fromcertain flow meters, depending on the measurement principle. For the purposeof finding means to determine when back flow prevails, LDV measurementswere also carried out. These measurements were compared with measurementsusing a vortex flow meter together with a new signal processing technique basedon wavelet analysis. The comparison showed that this technique may have apotential to measure pulsating flow rates accurately.Descriptors: Flow measuring, compressible flow, steady flow, pulsating flow,hot-wire anemometry, cold-wire anemometry.

    Fulltekst (pdf)
    FULLTEXT02
  • 3.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Kalpakli, Athanasia
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Örlü, Ramis
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Alfredsson, Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Review on the sensed temperature in cold-wire and hot-wire anemometry2010Rapport (Annet vitenskapelig)
    Abstract [en]

    Instantaneous velocity and temperature measurements by means of hot-wire and coldwires have become a standard technique used in almost every fluid dynamic research laboratory. Nonetheless, when it comes to compressible flows in applied fields, there seems to remain a need for clarification on which temperature is actually measured by a cold-wire and which temperature a hot-wire senses as its fluid temperature. The present paper reviews the view present in the literature and presents additional experimental evidence, that it is indeed the recovery temperature that is measured by a cold-wire and that this is also the temperature needed to compensate hot-wire readings in nonisothermal compressible flows

  • 4.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Segaline, Antonio
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Reifarth, Simon
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinkonstruktion (Avd.). KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Örlü, Ramis
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Alfredsson, Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Vortex shedding flow meters: accuracy assessment and extension towards industrial configurationsArtikkel i tidsskrift (Annet vitenskapelig)
  • 5.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Tillmark, Nils
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Alfredsson, Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    A pulsating flow rig for analyzing turbocharger performance2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

     

    Drastic improved performance of IC-engines requires efforts along many lines, where gas management is one important area. Although simulation intensive research and design tools are becoming more and more in use, they still need to be verified through accurate experiments. This is especially so for the turbocharger, an essential component for improved performance that is working in a highly complex environment. In this paper we describe a new test facility where a pulsed flow can be generated and the pulses accurately quantified trough a traversed hot-wire flow meter.

  • 6.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Tillmark, Nils
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Alfredsson, Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    The corona mass flow meter2008Konferansepaper (Fagfellevurdert)
  • 7.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Tillmark, Nils
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Alfredsson, Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    What does the hot-wire measure?2012Rapport (Fagfellevurdert)
    Abstract [en]

     

    Fulltekst (pdf)
    fulltext
  • 8.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Tillmark, Nils
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Alfredsson, Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Örlü, Ramis
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    A flow facility for the characterization of pulsatile flows2012Inngår i: Flow Measurement and Instrumentation, ISSN 0955-5986, E-ISSN 1873-6998, Vol. 26, s. 10-17Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper a new flow facility for studies of pulsating flows is described. The pulsating flow is generated by means of a rotating valve and the flow is quantified through a newly developed flow measurement module accurately measuring the phase averaged flow distribution. The measuring probe of the module consists of a hot/cold-wire pair that enables both the mass flux and recovery temperature to be measured simultaneously. Calibrations of both the hot and cold wire are done in-situ in steady flow by means of a Pitot tube and a thermocouple. Moreover, the phase averaged flow distribution can be obtained by an automatic traverse of the measuring probe across the pipe cross section in both the radial and azimuthal directions. In the paper we exemplify and describe the flow properties, using the new flow measurement module, both in steady and pulsating flow.

  • 9.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Tillmark, Nils
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Örlü, Ramis
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Alfredsson, Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    A pulsating flow rig for analyzing turbocharger performanceArtikkel i tidsskrift (Annet vitenskapelig)
  • 10.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för teknikvetenskap (SCI), Centra, Centrum för förbränningsteknik, CICERO.
    Örlü, Ramis
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för teknikvetenskap (SCI), Centra, Centrum för förbränningsteknik, CICERO.
    Segalini, Antonio
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Stabilitet, Transition, Kontroll. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Alfredsson, P. Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för teknikvetenskap (SCI), Centra, Centrum för förbränningsteknik, CICERO.
    Time-resolved measurements with a vortex flowmeter in a pulsating turbulent flow using wavelet analysis2010Inngår i: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 21, nr 12, s. 123001-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Vortex flowmeters are commonly employed in technical applications and are obtainable in a variety of commercially available types. However their robustness and accuracy can easily be impaired by environmental conditions, such as inflow disturbances and/or pulsating conditions. Various post-processing techniques of the vortex signal have been used, but all of these methods are so far targeted on obtaining an improved estimate of the time-averaged bulk velocity. Here, on the other hand, we propose, based on wavelet analysis, a straightforward way to utilize the signal from a vortex shedder to extract the time-resolved and thereby the phase-averaged velocity under pulsatile flow conditions. The method was verified with hot-wire and laser Doppler velocimetry measurements.

  • 11.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Örlü, Ramis
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Segalini, Antonio
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Tillmark, Nils
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Alfredsson, Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Experimental analysis of turbocharger interaction with a pulsatile flow through time-resolved flow measurements upstream and downstream of the turbine2012Inngår i: Institution of Mechanical Engineers - 10th International Conference on Turbochargers and Turbocharging, 2012, s. 405-415Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The inflow to and outflow from turbochargers are highly complex and, in particular, pulsating. Nevertheless, most studies of turbocharger performance are conducted under steady conditions. Hence, there is a great interest in determining and understanding turbocharger performance maps under pulsatile conditions. The highly complex flow field constitutes a challenge for time-resolved flow measurements by means of conventional measurement techniques. In a recent paper by Laurantzon et al [Meas. Sci. Technol. 20 123001 (2010)], time-resolved bulk flow measurements under pulsatile conditions have been obtained via wavelet analysis of the signal from a vortex flow meter. Here, this method has been used in order to obtain time-resolved performance maps based on the mass flow both upstream and down-stream of the turbine. The results show that the turbine has a large damping effect on the mass flow pulsations, but that the pulse shape is to a high degree preserved while passing through the turbine, and that the time-dependent filling and emptying of the turbine case make the quasi-steady assumption invalid, if the whole turbine stage is considered.

  • 12.
    Laurantzon, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Örlü, Ramis
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Tillmark, Nils
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Alfredsson, Henrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Response of common flowmeters to unsteady flow2012Rapport (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
1 - 12 of 12
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  • en-GB
  • en-US
  • fi-FI
  • nn-NO
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