Concept-Based Modeling as a Method Combining Digital and Analogue Means for Problem-Solving

refereedrefRefereedRefereegranskatFagfellevurdertconferencePaperkonConference paperKonferensbidragKonferansepaperproceedingpublishedPaperSjödénBjörn1977-autHögskolan i Halmstad, Akademin för lärande, humaniora och samhälleorcid.org=0000-0002-4650-2976diva-portal.org=authority-person:59343LiljaPatrik1973-autHögskolan i Halmstad, Akademin för lärande, humaniora och samhälleorcid.org=0000-0001-7252-4610diva-portal.org=authority-person:70772LöfgrenHans1968-autHögskolan i Halmstad, Akademin för företagande, innovation och hållbarhetorcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737Högskolan i HalmstadAkademin för lärande, humaniora och samhällepblHögskolan i HalmstadAkademin för företagande, innovation och hållbarhetpblConcept-Based Modeling as a Method Combining Digital and Analogue Means for Problem-SolvingengChamSpringer20232022-12-22T18:57:45978-3-031-31391-2978-3-031-31392-9https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-4903910.1007/978-3-031-31392-9_2dwbrg0w6bk90zd6k2-s2.0-85161393494textLecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering1867-82111867-822X493Concept-Based ModelingDigitalAnalogueProblem-SolvingComputer Algebra SystemSocial SciencesEducational SciencesDidacticsSamhällsvetenskapUtbildningsvetenskapDidaktikSocial SciencesEducational SciencesSamhällsvetenskapUtbildningsvetenskapPedagogyPedagogikLEADSResearch subjectLEADSResearch subjectIn this paper we present Concept-Based Modeling (CBM), an innovative pedagogical method for problem-solving in engineering education, which combines analogue and digital tools. We outline the scientific rationale for CBM and discuss how it compares to traditional teaching with respect to optimizing the pedagogical value of both analogue and digital means. CBM is based on conceptual modeling of quantities derived directly from first principles and streamlined for the use of computer algebra systems (CAS). The method was evaluated in a pilot survey in a statics course for engineering students in their freshman year at Halmstad University. We conclude that CBM improves students’ problem-solving skills by the reciprocal action between conceptual understanding and modeling of a problem. Student evaluations suggest that CBM enables students to handle more realistic problems and that CAS as a professional tool prepares them for their future working life. Future studies will address CBM for more advanced courses, as the students’ knowledge develops over time. © 2022 The Authors. Design, Learning, and Innovation7th EAI International Conference, DLI 2022, Faro, Portugal, November 21-22, 2022, Proceedings2237Eva Brooks, Jeanette Sjöberg, Anders Kalsgaard Møller, Emma EdstrandEAI DLI 2022 - 7th EAI International Conference on Design, Learning & Innovation, Faro, Portugal, November 21-22, 2022bjosjohh2022-12-222025-02-18diva2:1721866refereedrefRefereedRefereegranskatFagfellevurdertconferencePaperkonConference paperKonferensbidragKonferansepaperproceedingpublishedPaperPhilipRonyautAmrita University, Coimbatore, IndiaLöfgrenHans1968-autHögskolan i Halmstad, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS)orcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737Högskolan i HalmstadAkademin för företagande, innovation och hållbarhetRydberglaboratoriet för tillämpad naturvetenskap (RLAS)pblExperimental Verification of an Instrument to Test Flooring MaterialsengBristolInstitute of Physics Publishing (IOPP)20182019-01-11T16:27:00https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-3874610.1088/1757-899X/310/1/0121210004460720001212-s2.0-85043698814012121https://doi.org/10.1088/1757-899X/310/1/012121textIOP Conference Series: Materials Science and Engineering1757-89811757-899X310coefficients of the floorFluid modelleast square methodlinear dynamicsMatlabBuilding materialsEnergy dissipationLeast squares approximationsManufactureDifferent floorsElastic modelingExperimental verificationFlooring materialsFluid modelingLeast square methodsStandardized testingFloorsEngineering and TechnologyMaterials EngineeringTeknik och teknologierMaterialteknikThe focus of this work is to validate the fluid model with different flooring materials and the measurements of an instrument to test flooring materials and its force attenuating capabilities using mathematical models to describe the signature and coefficients of the floor. The main contribution of the present work focus on the development of a mathematical fluid model for floors. The aim of the thesis was to analyze, compare different floor materials and to study the linear dynamics of falling impacts on floors. The impact of the hammer during a fall is captured by an accelerometer and response is collected using a picoscope. The collected data was analyzed using matlab least square method which is coded as per the fluid model. The finding from this thesis showed that the fluid model works with more elastic model but it doesn't work for rigid materials like wood. The importance of parameters like velocity, mass, energy loss and other coefficients of floor which influences the model during the impact of falling on floors were identified and a standardized testing method was set. © Published under licence by IOP Publishing Ltd.IOP Conference SeriesMaterials Science and EngineeringInternational Conference on Advances in Materials and Manufacturing Applications 2017, IConAMMA 2017, 17-19 August, 2017https://hh.diva-portal.org/smash/get/diva2:1278086/FULLTEXT01.pdfjonolshh2019-01-112021-08-13diva2:1278086refereedrefRefereedRefereegranskatFagfellevurdertarticleartArticle in journalArtikel i tidskriftArtikkel i tidsskriftarticleLöfgrenHans1968-autHögskolan i Halmstad, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS)orcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737Högskolan i HalmstadAkademin för företagande, innovation och hållbarhetRydberglaboratoriet för tillämpad naturvetenskap (RLAS)pblA first order friction model for lubricated sheet metal formingengMelville, NYAmerican Institute of Physics (AIP)20182018-09-17T14:43:56https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-3800710.1016/j.taml.2018.01.0020004372239000112-s2.0-85049335252https://doi.org/10.1016/j.taml.2018.01.002textFriction modelLubricationSheet metal formingEngineering and TechnologyMechanical EngineeringOther Mechanical EngineeringTeknikMaskinteknikAnnan maskinteknikThis paper presents the derivation of a first order friction model for lubricated sheet metal forming. Assuming purely plastic real contacts, Newton's law of viscosity, and a square root behavior of the hydrodynamic coefficient of friction with respect to the hydrodynamic Hersey parameter an analytic model is found. The model predicts the coefficient of friction as a function of the relative pressure, the relative Hersey parameter and the real contact coefficient of friction. Questions about local and global friction are raised in the validation of the model against flat tool sheet experiments. For some flat tool sheet experiments reasonable agreements are obtained assuming a rigid punch pressure distribution. The restricted number of user inputs makes the model useful in early tool design simulations. © 2018 The Authors. Published by Elsevier Ltd on behalf of The Chinese Society of Theoretical and Applied MechanicsTheoretical and Applied Mechanics Letters2095-0349815761PublishedStiftelsen för strategisk forskning (SSF) [PV08-0041]hanlofhh2018-09-172025-02-14diva2:1248877otherpopOther (popular science, discussion, etc.)Övrig (populärvetenskap, debatt, mm)Annet (populærvitenskap, debatt, mm)conferencePaperkonConference paperKonferensbidragKonferansepaperproceedingpublishedPaperGåårdAndersautKarlstads Universitet, Karlstad, SverigeLöfgrenHans1968-autHögskolan i Halmstad, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS)orcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737NilssonBertil1953-autHögskolan i Halmstad, Tillämpad matematik och fysik (MPE-lab)diva-portal.org=authority-person:60056HallbäckNilsautKarlstads Universitet, Karlstad, SverigeHögskolan i HalmstadAkademin för företagande, innovation och hållbarhetRydberglaboratoriet för tillämpad naturvetenskap (RLAS)pblHögskolan i HalmstadAkademin för informationsteknologiHalmstad Embedded and Intelligent Systems Research (EIS)Tillämpad matematik och fysik (MPE-lab)pblInförandet av Computer Based Mathematics (CBM) i ingenjörsutbildningarswe20172018-09-23T10:53:00https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-38041https://www.chalmers.se/sv/konferens/utvecklingskonferensen2017/PublishingImages/Program.pdftextSocial SciencesEducational SciencesPedagogySamhällsvetenskapUtbildningsvetenskapPedagogikCBM är ett koncept som innebär användning av datorn och matematikprogramvaror som huvudverktyg i under-visningen. Istället för att som i traditionell undervisning kombinera handräkning med datorlabbar ligger tyngdpunkten i en CBM-kurs på datoriserade beräkningsverktyg. Härav för-flyttas fokus mot konceptförtåelse, modellering och tolkning av resultat. Vid Högskolan i Halmstad och Karlstads Universitet finns idag flera kurser baserat på CBM. Kvantitativt har införandet lett till ökad studentgenomströmning samtidigt som innehållet i kurser har ökat. Kvalitativa markörer, såsom studentens egen uppfattning om konceptuell förståelse och nyfikenhet inom ämnet, har baserat på kursvärderingar också ökat. </titleInfo></relatedItem><name type="conference"><namePart>6:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar, Chalmers tekniska högskola, 22 november – 23 november 2017</namePart></name><location><url displayLabel="fulltext:print" note="free" access="raw object">https://hh.diva-portal.org/smash/get/diva2:1250278/FULLTEXT01.pdf</url></location><recordInfo><recordOrigin>hanlof</recordOrigin><recordContentSource>hh</recordContentSource><recordCreationDate>2018-09-23</recordCreationDate><recordChangeDate>2018-10-31</recordChangeDate><recordIdentifier>diva2:1250278</recordIdentifier></recordInfo></mods><mods xmlns="http://www.loc.gov/mods/v3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" version="3.7" xsi:schemaLocation="http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-7.xsd"><genre authority="diva" type="contentTypeCode">refereed</genre><genre authority="svep" type="contentType">ref</genre><genre authority="diva" type="contentType" lang="eng">Refereed</genre><genre authority="diva" type="contentType" lang="swe">Refereegranskat</genre><genre authority="diva" type="contentType" lang="nor">Fagfellevurdert</genre><genre authority="diva" type="publicationTypeCode">article</genre><genre authority="svep" type="publicationType">art</genre><genre authority="diva" type="publicationType" lang="eng">Article in journal</genre><genre authority="diva" type="publicationType" lang="swe">Artikel i tidskrift</genre><genre authority="diva" type="publicationType" lang="nor">Artikkel i tidsskrift</genre><genre authority="kev" type="publicationType" lang="eng">article</genre><name type="personal" authority="hh" xlink:href="zladim"><namePart type="family">Dimkovski</namePart><namePart type="given">Zlate</namePart><role><roleTerm type="code" authority="marcrelator">aut</roleTerm></role><affiliation>Högskolan i Halmstad, Funktionella ytor</affiliation><description>orcid.org=0000-0003-3149-4296</description><description>diva-portal.org=authority-person:33733</description></name><name type="personal" authority="hh" xlink:href="frecab"><namePart type="family">Cabanettes</namePart><namePart type="given">Frédéric</namePart><role><roleTerm type="code" authority="marcrelator">aut</roleTerm></role><affiliation>Högskolan i Halmstad, Funktionella ytor</affiliation><description>orcid.org=0000-0002-9447-9635</description><description>diva-portal.org=authority-person:33732</description></name><name type="personal" authority="hh" xlink:href="hanlof"><namePart type="family">Löfgren</namePart><namePart type="given">Hans</namePart><role><roleTerm type="code" authority="marcrelator">aut</roleTerm></role><affiliation>Högskolan i Halmstad, Funktionella ytor</affiliation><description>orcid.org=0000-0003-0292-893X</description><description>diva-portal.org=authority-person:33737</description></name><name type="personal" authority="hh" xlink:href="cecilia"><namePart type="family">Anderberg</namePart><namePart type="given">Cecilia</namePart><role><roleTerm type="code" authority="marcrelator">aut</roleTerm></role><affiliation>Volvo Cars</affiliation><description>diva-portal.org=authority-person:61589</description></name><name type="personal"><namePart type="family">Ohlsson</namePart><namePart type="given">Robert</namePart><role><roleTerm type="code" authority="marcrelator">aut</roleTerm></role><affiliation>Volvo Powertrain</affiliation></name><name type="personal" authority="hh" xlink:href="bgro"><namePart type="family">Rosén</namePart><namePart type="given">Bengt-Göran</namePart><role><roleTerm type="code" authority="marcrelator">aut</roleTerm></role><affiliation>Högskolan i Halmstad, Funktionella ytor</affiliation><description>orcid.org=0000-0001-8058-1252</description><description>diva-portal.org=authority-person:33726</description></name><name type="corporate" authority="hh" xlink:href="3921"><namePart>Högskolan i Halmstad</namePart><namePart>Akademin för ekonomi, teknik och naturvetenskap</namePart><namePart>Maskinteknisk produktframtagning (MTEK)</namePart><namePart>Funktionella ytor</namePart><role><roleTerm type="code" authority="marcrelator">pbl</roleTerm></role></name><titleInfo lang="eng"><title>Optimisation of Cylinder Liner Surface Finish by Slide HoningengLondonMechanical Engineering Publ.20122011-03-25T16:10:00https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1464510.1177/09544054103961540003054816000012-s2.0-84860231449text3D characterizationdiamond honingliner surface finishmixed lubrication simulationEngineering and TechnologyMaterials EngineeringManufacturing, Surface and Joining TechnologyTeknik och teknologierMaterialteknikBearbetnings-, yt- och fogningsteknikTECHNOLOGYMaterials scienceOther processing/assemblyTEKNIKVETENSKAPTeknisk materialvetenskapÖvrig bearbetning/sammanfogningCylinder liner surface finish controls the frictional losses, oil consumption, and emissions of internal combustion engines to a large extent. In order to minimize such losses, it is important to optimize the liner surface topography by a consistent and more productive finishing process such as slide honing. This process employs diamond abrasives and has been recently introduced in the automotive industry. In this study, its potentials are explored, especially the winning combination of its key process parameters: the base honing pressure and plateau honing time that would yield an optimal liner surface finish. A number of truck engine liners were slide-honed by using different process parameters, samples of the liners were cut, and three-dimensional (3D) surface measurements were taken on a white light interferometer. Then, among others, the (deep honing) groove parameters, specific for liner surfaces, were computed from the measurements for building a large database for comparison and correlation. By simulating the contact and fluid mechanics between the measured liner topographies and a twin land oil control ring under mixed lubrication conditions, the friction mean effective pressure and oil passage rate for a range of engine speeds were calculated. These two parameters represent the liner's function associated with the engine's friction and oil consumption respectively. The results show that the lowest friction and oil flow are highly correlated with surfaces having smoother plateaus and smaller valleys, finished by using lower base honing pressure and longer plateau honing time. High correlations between the 3D roughness parameters were also found, enabling the selection and use of more stable and robust parameters in the quality control of the liner's surface finish. © IMechE 2012.Proceedings of the Institution of mechanical engineers. Part B, journal of engineering manufacture0954-40542041-29752264575584Publishedzladimhh2011-03-252018-03-23diva2:406501refereedrefRefereedRefereegranskatFagfellevurdertarticleartArticle in journalArtikel i tidskriftArtikkel i tidsskriftarticleletterLöfgrenHans Bertil1968-autHögskolan i Halmstad, Funktionella ytororcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737Högskolan i HalmstadAkademin för ekonomi, teknik och naturvetenskapMaskinteknisk produktframtagning (MTEK)Funktionella ytorpblA solution to the hydrodynamic lubrication of a circular point contact sliding over a flat surface with cavitationengMelville, NYAmerican Institute of Physics (AIP)20122012-05-31T12:17:00https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1779210.1063/2.12032042-s2.0-85040522128032004https://doi.org/10.1063/2.1203204textReynolds equationanalytical solutioncavitationpoint contactEngineering and TechnologyMechanical EngineeringOther Mechanical EngineeringTeknikMaskinteknikAnnan maskinteknikTECHNOLOGYTEKNIKVETENSKAPThis letter presents an analytical solution to the hydrodynamic lubrication of a circular point contact sliding over a flat surface with cavitation. The solution is found by solving the Reynolds equation with Reynolds boundary condition for cavitation. The cavitation boundary is shown to be straight lines directed 108.4° against the sliding direction. The result is experimentally verified in the limit of large values of viscosity, sliding velocity and radius of a spherical ball. The solution raises questions about the coupling between cavitation and film rupture and can be used as an independent check on the validity of numerical solutions.Theoretical and Applied Mechanics Letters2095-034923PublishedStiftelsen för strategisk forskning (SSF)hanlofhh2012-05-312025-02-14diva2:529811refereedrefRefereedRefereegranskatFagfellevurdertconferencePaperkonConference paperKonferensbidragKonferansepaperproceedingpublishedPaperDimkovskiZlateautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0003-3149-4296diva-portal.org=authority-person:33733AnderbergCeciliaautVolvo Power Train Corp., Volvo Group, Göteborg, Swedendiva-portal.org=authority-person:61589CabanettesFrédéricautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0002-9447-9635diva-portal.org=authority-person:33732LöfgrenHansautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737RosénB.-G.autHögskolan i Halmstad, Funktionella ytororcid.org=0000-0001-8058-1252diva-portal.org=authority-person:33726Högskolan i HalmstadAkademin för ekonomi, teknik och naturvetenskapMaskinteknisk produktframtagning (MTEK)Funktionella ytorpblInfluence of Different Cylinder Liner Surfaces on Their Performance with the Twin Land Oil Control Ring in a Car Engineeng20112011-03-25T16:20:00https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-14647textEngineering and TechnologyMaterials EngineeringManufacturing, Surface and Joining TechnologyTeknik och teknologierMaterialteknikBearbetnings-, yt- och fogningsteknikProceedings of the 13th International Conference on Metrology and Properties of Engineering SurfacesThe 13th International Conference on Metrology and Properties of Engineering Surfaces, Met & Props 2011, 12-15 April 2011, Twickenham Stadium, London, UKzladimhh2011-03-252018-03-23diva2:406507refereedrefRefereedRefereegranskatFagfellevurdertconferencePaperkonConference paperKonferensbidragKonferansepaperproceedingpublishedPaperCabanettesFrédéric1982-autHögskolan i Halmstad, Funktionella ytororcid.org=0000-0002-9447-9635diva-portal.org=authority-person:33732LöfgrenHans BertilautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737RosénBengt-GöranautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0001-8058-1252diva-portal.org=authority-person:33726Högskolan i HalmstadAkademin för ekonomi, teknik och naturvetenskapMaskinteknisk produktframtagning (MTEK)Funktionella ytorpblEvaluation of manufacturing processes for cam/roller contacteng20112011-09-26T07:30:00https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-16339textEngineering and TechnologyMechanical EngineeringOther Mechanical EngineeringTeknikMaskinteknikAnnan maskinteknikTECHNOLOGYMaterials scienceSurface engineeringTEKNIKVETENSKAPTeknisk materialvetenskapYtbehandlingsteknikThe 4th Swedish Production Symposium 2011 (SPS'11), Lund University, Sweden, 3 - 5 May 2011frecabhh2011-09-262025-02-14diva2:443450refereedrefRefereedRefereegranskatFagfellevurdertconferencePaperkonConference paperKonferensbidragKonferansepaperproceedingpublishedPaperCabanettesFrédéric1982-autHögskolan i Halmstad, Funktionella ytororcid.org=0000-0002-9447-9635diva-portal.org=authority-person:33732LöfgrenHans BertilautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737RosénBengt-GöranautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0001-8058-1252diva-portal.org=authority-person:33726Högskolan i HalmstadAkademin för ekonomi, teknik och naturvetenskapMaskinteknisk produktframtagning (MTEK)Funktionella ytorpblThe impact of manufacturing processes on Automotive Cam/Roller Contacteng20112011-09-26T07:28:00https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-16338textEngineering and TechnologyMechanical EngineeringOther Mechanical EngineeringTeknikMaskinteknikAnnan maskinteknikThe 13th International Conference on Metrology and Properties of Engineering Surfaces, 12-15 April 2011, Twickenham Stadium, UKfrecabhh2011-09-262025-02-14diva2:443449refereedrefRefereedRefereegranskatFagfellevurdertconferencePaperkonConference paperKonferensbidragKonferansepaperproceedingpublishedPaperRosénBengt-GöranautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0001-8058-1252diva-portal.org=authority-person:33726DimkovskiZlateautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0003-3149-4296diva-portal.org=authority-person:33733CabanettesFrédéricautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0002-9447-9635diva-portal.org=authority-person:33732LöfgrenHansautHögskolan i Halmstad, Funktionella ytororcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737Högskolan i HalmstadAkademin för ekonomi, teknik och naturvetenskapMaskinteknisk produktframtagning (MTEK)Funktionella ytorpblControlling variation of topography towards robust surface performanceengWorcester, USAWorcester Polytechnic Institute20102011-09-27T10:28:00978-1-4507-4290-0https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-16360textEngineering and TechnologyMechanical EngineeringTeknik och teknologierMaskinteknikProceedings of the 2nd International Conference on Surface MetrologyOctober 25-27, 2010, Worcester Polytechnic Institute, Worcester, MA, USA4351Bergstrom T. et al.2nd International Conference on Surface Metrology, Worcester, MA, USA, October 25-27, 2010zladimhh2011-09-272016-08-15diva2:443841sciencevetOther academicÖvrigt vetenskapligtAnnet vitenskapeligconferencePaperkonConference paperKonferensbidragKonferansepaperproceedingpresentationBååthLars B.autHögskolan i Halmstad, Maskinteknisk produktframtagning (MTEK)orcid.org=0000-0002-4826-019Xdiva-portal.org=authority-person:20574LöfgrenHansautHögskolan i Halmstad, Maskinteknisk produktframtagning (MTEK)orcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737Högskolan i HalmstadAkademin för ekonomi, teknik och naturvetenskapMaskinteknisk produktframtagning (MTEK)pblNy teknologi för avisning av vindkraftvingarswe20082008-09-30T11:09:00https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-19952082/2390textIsbildningVindkraftverkAvisningEngineering and TechnologyTeknik och teknologierTECHNOLOGYTEKNIKVETENSKAPVindforsks programkonferens, 14-15 maj 2008, KTH Stockholmhttps://hh.diva-portal.org/smash/get/diva2:239213/POPULARSUMMARY01.pdfimporthh2008-09-302016-08-15diva2:239213sciencevetOther academicÖvrigt vetenskapligtAnnet vitenskapeligreportrapReportRapportRapportbookBååthLars1948-autHögskolan i Halmstad, Fotonik och mikrovågsteknikorcid.org=0000-0002-4826-019Xdiva-portal.org=authority-person:20574LöfgrenHansautHögskolan i Halmstad, Maskinteknisk produktframtagning (MTEK)orcid.org=0000-0003-0292-893Xdiva-portal.org=authority-person:33737Högskolan i HalmstadAkademin för ekonomi, teknik och naturvetenskapMaskinteknisk produktframtagning (MTEK)Fotonik och mikrovågsteknikpblHögskolan i HalmstadAkademin för ekonomi, teknik och naturvetenskapMaskinteknisk produktframtagning (MTEK)pblNy teknik för avisning av vindkraftsvingarsweNew Technologies for de-icing Wind TurbinesengHalmstadHalmstad University20082009-12-21T14:41:0054https://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-3629http://cvi.se/uploads/pdf/Kunskapsdatabas%20teknik/forskningsresultat/V-238_Bååth_Löfgren_avisning.pdftextVindforsk tillämpade programmetV-238De-icingWind turbinesEngineering and TechnologyTeknik och teknologierTECHNOLOGYTEKNIKVETENSKAPThis is a pilot study to investigate icing on wings of wind power turbines. In this report we present and discuss various ways and means to either heat water droplets or melt ice when formed on the wings of wind turbines. The situation is different from icing on wings of airplanes in that (1) the wings of wind turbines spend all of their time in the atmosphere where the risk of icing is highest and (2) the speed of wing to air varies over the wing where it is constant for an airplane. The form of the wind turbine wings also varies from tip to centre, to compensate for the varying relative air speed.We have concentrated on icing conditions at temperatures -10°C – 0°C and droplet sizes of 1-10 μm. Icing occurs also at much lower temperatures, but this will probably be because of direct freezing of water vapour to ice. This is presently outside the scope of our pilot project report.We conclude that<ul><li>The form of the wing, especially on the contact area may be crucial to the icing problem.</li><li>Also the nano-metric structure of the wing surface can probably be designed so that the water droplets have a minimized contact area to the wing.</li></ul>Our pilot investigation also suggests the following:<ul><li>Microwaves are much too inefficient to heat water or melt ice. Direct microwave devices should therefore not be developed. Indirect heating with microwaves is possible.</li><li>Millimeter waves are sufficiently efficient, but the generation is most probably too inefficient to be of any practical use.</li><li>Infrared waves are very efficient to heat water and melt ice and should be investigated.</li><li>Heat conduction is also efficient and should be pursued. Using microwaves to heat the wing surface which then conduct heat to the water/ice is a very efficient and robust method.</li></ul>Our pre-study suggests that the solution to avoid icing or de-ice wings of wind turbines most probably is not one single technology. The form and surface structure of the wings play important role for icing conditions. Both variables have to be modified depending on the latitude and atmospheric climate. The surface structure also has to be designed to vary over the wing, both along and across to be optimized for the mean conditions at the site. In addition, heating of the impact area, or at least the possibility to heat this, may be important to avoid loss of energy output due to ice.Further research is required. We strongly suggest investigating the water droplet flow over the wing as function of the cross section form, and the contact with the wing surface as function of the surface structure (e.g. Lotus effect).The present report is the result of a pre-study project. We will now continue with a deeper project which will concentrate on the form and surface structure suggestions which results from our analysis and flow simulations.Denna rapport presenterar resultatet av en förstudie om tekniker för avisning av vindkraftverk. Rapporten presenterar och diskuterar möjliga metoder och tekniker för att antingen värma vattendroppar till över fryspunkten, eller smälta is som har bildats på vingen. Problematiken för vingar på vindkraftverk skiljer sig markant från nedisning av flygplansvingar i att: (1) vingar på vindkraftverk tillbringar all sin tid i den delen av atmosfären där risken för nedisning är som störst; och (2) hastigheten för vingen mot luft varierar med avstånd från rotationscentrum medan den är konstant över vingen på ett flygplan. Formen på vingen på ett vindkraftverk varierar också från toppen in till centrum för att kompensera för variationen av relativ hastighet mot luften.Rapporten koncentreras på isbildning inom temperaturintervallet -10°C – 0°C och droppstorlekar av 1- 10 μm. Nedisning sker även vid mycket lägre temperaturer, men då sker troligen isbildningen direkt från vattenånga.Vi drar följande slutsatser från vår studie:<ul><li>Formen på vingen, speciellt vid kontaktytan mot gasflödet, kan ha betydelse för nedisning.</li><li>Nano-strukturen av ytan på vingen kan troligen konstrueras så att vattendropparna får enminimal kontaktyta mot vingen.</li></ul>Vår förstudie visar dessutom:<ul><li>Mikrovågor är alltför ineffektiva för att värma rent vatten eller smälta is. Tekniker för direktstrålning av mikrovågor mot vatten eller is på vingar bör således inte vidare utvecklas.</li><li>Millimetervågor är tillräckligt effektiva, men generationen av vågor på så höga frekvenser ärtroligen alltför ineffektiv för att detta ska vara en möjlig väg framåt.</li><li>Infrarött ljus är mycket effektivt för att värma vattendroppar eller smälta is och bör undersökasvidare.</li><li>Värmeledning är också effektivt och bör utvecklas. En robust och effektiv metod kan vara attvärma vingytan med mikrovågor så att kontakten mot den varma ytan smälter isen.</li></ul>Vår förstudie visar att problematiken med undvikande av isbildning på, eller avisning av, vindkraftsverk inte har sitt svar i en enda teknik. Formen på vingen och strukturen på dess yta kan spela en viktig roll i förhållandena för isbildning. Båda dessa variabler kan behöva varieras beroende på latitud och atmosfäriskt klimat. Ytstrukturen måste troligen också variera över vingytan, både längs med vingen och tvärs, för att optimera för de lokala förhållandena. Dessutom kan smältning av is medelst värmning av vingytan vara en viktig extra möjlighet för att undvika effektförluster.Mer forskning är nödvändig, men vi sammanfattar att det största intresset just nu är att studera flödet av droppar över vingen som funktion av tvärsnittsytans form och kontakten mellan vingytan som funktion av ytstrukturen (t.ex. Lotus effekten).Denna rapport är resultatet av ett förstudieprojekt. Vi ämnar nu fortsätta med ett djupare forskningsprojekt som koncentreras på formen och ytstrukturen enligt vad som framkommit av vår analys och våra datorsimuleringar.Project 30988-1/V-238https://hh.diva-portal.org/smash/get/diva2:281775/FULLTEXT01.pdfbaathhh2009-12-172017-11-29diva2:281775

Search staff

Personal vid Högskolan

Hans Löfgren

Senior Lecturer

( School of Business, Innovation and Sustainability )

Latest publications