{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,10]],"date-time":"2026-01-10T18:38:19Z","timestamp":1768070299102,"version":"3.49.0"},"reference-count":19,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2013,8,19]],"date-time":"2013-08-19T00:00:00Z","timestamp":1376870400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Miniaturized thermal flow sensors have opened the doors for a large variety of new applications due to their small size, high sensitivity and low power consumption. Theoretically, very small detection limits of air velocity of some micrometers per second are achievable. However, the superimposed free convection is the main obstacle which prevents reaching these expected limits. Furthermore, experimental investigations are an additional challenge since it is difficult to generate very low flows. In this paper, we introduce a physical method, capable of generating very low flow values in the mixed convection region. Additionally, we present the sensor characteristic curves at the zero flow case and in the mixed convection region. Results show that the estimated minimum detectable air velocity by the presented method is 0.8 mm\/s. The equivalent air velocity to the noise level of the sensor at the zero flow case is about 0.13 mm\/s.<\/jats:p>","DOI":"10.3390\/s130810944","type":"journal-article","created":{"date-parts":[[2013,8,19]],"date-time":"2013-08-19T12:27:44Z","timestamp":1376915264000},"page":"10944-10953","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Minimum Detectable Air Velocity by Thermal Flow Sensors"],"prefix":"10.3390","volume":"13","author":[{"given":"Safir","family":"Issa","sequence":"first","affiliation":[{"name":"IMSAS (Institute for Microsensors, Actuators and Systems), Microsystems Center Bremen (MCB), University of Bremen, Otto-Hahn-Allee, Bld. NW1, Bremen D-28359, Germany"}]},{"given":"Walter","family":"Lang","sequence":"additional","affiliation":[{"name":"IMSAS (Institute for Microsensors, Actuators and Systems), Microsystems Center Bremen (MCB), University of Bremen, Otto-Hahn-Allee, Bld. NW1, Bremen D-28359, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2013,8,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"550","DOI":"10.3390\/mi3030550","article-title":"Micromachined thermal flow sensors\u2014A review","volume":"3","author":"Kuo","year":"2012","journal-title":"Micromachines"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"225","DOI":"10.3390\/mi3020225","article-title":"Micromachined flow sensors in biomedical applications","volume":"3","author":"Silvestri","year":"2012","journal-title":"Micromachines"},{"key":"ref_3","unstructured":"(2008). JCGM 200: 2008\u2014International Vocabulary of Metrology Basic and General Concepts and Associated Terms (VIM), JCGM. [3rd ed.]."},{"key":"ref_4","unstructured":"Incropera, F.P., and DeWitt, D.P. (2002). Fundamentals of Heat and Mass Transfer, John Wiley & Sons. [5th ed.]."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"958","DOI":"10.1109\/16.52430","article-title":"Heat transport from a chip","volume":"37","author":"Lang","year":"1990","journal-title":"IEEE Trans. Electron. Devices"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"724","DOI":"10.1109\/19.772208","article-title":"Thermal flow measurements at Gr\/Re2 \u226b1 by silicon anemometry","volume":"48","year":"1999","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1016\/j.sna.2010.08.012","article-title":"A 2D thermal flow sensor with Sub-mW power consumption","volume":"163","author":"Cubukcu","year":"2010","journal-title":"Sens. Actuators A Phys."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Buchner, R., Bhargava, P., Sosna, C., Benecke, W., and Lang, W. (2007, January 28\u201331). Thermoelectric Flow Sensors with Monolithically Integrated Channel Structures for Measurements of Very Small Flow Rates. Atlanta, GA, USA.","DOI":"10.1109\/ICSENS.2007.4388529"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"359","DOI":"10.1007\/s00542-011-1409-5","article-title":"Modelling and evaluation of a thermal microfluidic sensor fabricated on plastic substrate","volume":"18","author":"Patsis","year":"2012","journal-title":"Microsyst. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1401","DOI":"10.1109\/JSEN.2013.2245320","article-title":"A CMOS MEMS capacitive flow sensor for respiratory monitoring","volume":"13","author":"Liao","year":"2013","journal-title":"IEEE Sens. J."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Ashauer, M., Glosch, H., Hedrich, F., Hey, N., Sandmaier, H., and Lang, W. (1998, January 25\u201329). Thermal Flow Sensor for Liquids and Gases. Heidelberg, Germany.","DOI":"10.1115\/IMECE1998-1280"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Kaanta, B.C., Chen, H., and Zhang, X. (2010). Novel device for calibration-free flow rate measurements in micro gas chromatographic systems. J. Micromech. Microeng.","DOI":"10.1088\/0960-1317\/20\/9\/095034"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"990","DOI":"10.1109\/JSEN.2006.888599","article-title":"Flip-chip packaging for a two-dimensional thermal flow sensor using a copper pillar bump technology","volume":"7","author":"Sun","year":"2007","journal-title":"IEEE Sens. J."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"262","DOI":"10.1016\/j.sna.2006.02.009","article-title":"A high temperature thermopile fabrication process for thermal flow sensors","volume":"130\u2013131","author":"Buchner","year":"2006","journal-title":"Sens. Actuators A Phys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1016\/j.sna.2011.02.023","article-title":"Response time of thermal flow sensors with air as fluid","volume":"172","author":"Sosna","year":"2011","journal-title":"Sens. Actuators A Phys."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"385","DOI":"10.3390\/mi2040385","article-title":"Modeling of the response time of thermal flow sensors","volume":"2","author":"Issa","year":"2011","journal-title":"Micromachines"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2140","DOI":"10.1016\/j.ijheatmasstransfer.2008.10.006","article-title":"Study of the sensitivity of a thermal flow sensor","volume":"52","author":"Kim","year":"2009","journal-title":"Int. J. Heat Mass Trans."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Johnson, J.B. (1928). Thermal agitation of electricity in conductors. Phys. Rev., 32.","DOI":"10.1103\/PhysRev.32.97"},{"key":"ref_19","unstructured":"Kester, W. Analog Devices MT-001 2005; Available online: http:\/\/www.locutus.it\/sundry\/MT-001.pdf."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/13\/8\/10944\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:48:45Z","timestamp":1760219325000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/13\/8\/10944"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2013,8,19]]},"references-count":19,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2013,8]]}},"alternative-id":["s130810944"],"URL":"https:\/\/doi.org\/10.3390\/s130810944","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2013,8,19]]}}}