{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T17:15:51Z","timestamp":1780334151898,"version":"3.54.1"},"reference-count":36,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,2,9]],"date-time":"2022-02-09T00:00:00Z","timestamp":1644364800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["2019YFB2005702"],"award-info":[{"award-number":["2019YFB2005702"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this article, novel thermal gas sensors with newly designed diffusion gas channels are proposed to reduce the flow-rate disturbance. Simulation studies suggest that by lowering the gas flow velocity near the hot film, the maximum normalized temperature changes caused by flow-rate variations in the two new designs (Type-H and Type-U) are decreased to only 1.22% and 0.02%, which is much smaller than in the traditional straight design (Type-I) of 20.16%. Experiment results are in agreement with the simulations that the maximum normalized flow-rate interferences in Type-H and Type-U are only 1.51% and 1.65%, compared to 24.91% in Type-I. As the introduced CO2 flow varied from 1 to 20 sccm, the normalized output deviations in Type-H and Type-U are 0.38% and 0.02%, respectively, which are 2 and 3 orders of magnitude lower than in Type-I of 10.20%. In addition, the recovery time is almost the same in all these sensors. These results indicate that the principle of decreasing the flow velocity near the hot film caused by the two novel diffusion designs can enhance the flow-rate independence and improve the accuracy of the thermal conductivity as well as the gas detection.<\/jats:p>","DOI":"10.3390\/s22041308","type":"journal-article","created":{"date-parts":[[2022,2,9]],"date-time":"2022-02-09T21:26:48Z","timestamp":1644442008000},"page":"1308","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Thermal Conductivity Gas Sensor with Enhanced Flow-Rate Independence"],"prefix":"10.3390","volume":"22","author":[{"given":"Jiayu","family":"Wang","sequence":"first","affiliation":[{"name":"Science and Technology on Microsystem Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanxiang","family":"Liu","sequence":"additional","affiliation":[{"name":"Science and Technology on Microsystem Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hong","family":"Zhou","sequence":"additional","affiliation":[{"name":"Science and Technology on Microsystem Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yi","family":"Wang","sequence":"additional","affiliation":[{"name":"Science and Technology on Microsystem Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ming","family":"Wu","sequence":"additional","affiliation":[{"name":"Science and Technology on Microsystem Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gang","family":"Huang","sequence":"additional","affiliation":[{"name":"China Astronaut Research and Training Center, Beijing 100094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9907-0188","authenticated-orcid":false,"given":"Tie","family":"Li","sequence":"additional","affiliation":[{"name":"Science and Technology on Microsystem Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"085017","DOI":"10.1088\/0960-1317\/23\/8\/085017","article-title":"Air flow sensing using micro-wire-bonded hair-like hot-wire anemometry","volume":"23","author":"Sadeghi","year":"2013","journal-title":"J. Micromech. Microeng."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4468","DOI":"10.1109\/TIE.2020.2984446","article-title":"CMOS MEMS Thermal Flow Sensor with Enhanced Sensitivity for Heating, Ventilation, and Air Conditioning Application","volume":"68","author":"Xu","year":"2021","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"7254","DOI":"10.1109\/JSEN.2019.2917697","article-title":"Temperature Effects of a Ceramic MEMS Thermal Wind Sensor Based on a Temperature-Balanced Mode","volume":"19","author":"Wang","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"111670","DOI":"10.1016\/j.sna.2019.111670","article-title":"MEMS-based thermal conductivity sensor for hydrogen gas detection in automotive applications","volume":"305","author":"Berndt","year":"2020","journal-title":"Sens. Actuators A Phys."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"15025","DOI":"10.1038\/micronano.2015.25","article-title":"Transient thermal response of micro-thermal conductivity detector (\u00b5TCD) for the identification of gas mixtures: An ultra-fast and low power method","volume":"1","author":"Mahdavifar","year":"2015","journal-title":"Microsyst. Nanoeng."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1016\/j.ijheatmasstransfer.2017.09.117","article-title":"Measurement of fluid thermal conductivity using a micro-beam MEMS sensor","volume":"117","author":"Takamatsu","year":"2018","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"025001","DOI":"10.1063\/1.4941067","article-title":"An integrated temperature-compensated flexible shear-stress sensor microarray with concentrated leading-wire","volume":"87","author":"Tang","year":"2016","journal-title":"Rev. Sci. Instrum."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"075021","DOI":"10.1088\/1361-665X\/ab1cc3","article-title":"High sensitive Polyimide-based single-walled carbon nanotube thermal film sensor for fluid shear stress measurements","volume":"28","author":"Gao","year":"2019","journal-title":"Smart Mater. Struct."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"105303","DOI":"10.1088\/1361-6501\/aadb1b","article-title":"Toward calibration-free wall shear stress measurement using a dual hot-film sensor and Kelvin bridges","volume":"29","author":"Liu","year":"2018","journal-title":"Meas. Sci. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1109\/JMEMS.2019.2954155","article-title":"Study on Fusion Mechanisms for Sensitivity Improvement and Measurable Pressure Limit Extension of Pirani Vacuum Gauges With Multi Heat Sinks","volume":"29","author":"Lai","year":"2019","journal-title":"J. Microelectromechanical Syst."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"8062","DOI":"10.1109\/JSEN.2016.2604206","article-title":"Investigating a Micro Pirani Gauge for Multi-Function Sensing","volume":"16","author":"Zhang","year":"2016","journal-title":"IEEE Sens. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/JMEMS.2017.2680738","article-title":"Investigation and Optimization of Pirani Vacuum Gauges With Monocrystal Silicon Heaters and Heat Sinks","volume":"26","author":"Zhang","year":"2017","journal-title":"J. Microelectromechanical Syst."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"483","DOI":"10.1016\/j.sna.2019.06.020","article-title":"Design and applications of MEMS flow sensors: A review","volume":"295","author":"Ejeian","year":"2019","journal-title":"Sens. Actuators A Phys."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"Q126","DOI":"10.1149\/2.0231906jss","article-title":"A Platinum Cantilever-Based Thermal Conductivity Detector for Ammonia Sensing Using the 3-Omega Technique","volume":"8","author":"Lotfi","year":"2019","journal-title":"ECS J. Solid State Sci. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4985","DOI":"10.1109\/JSEN.2020.2965217","article-title":"Simultaneous Flow and Thermal Conductivity Sensing on a Single Chip Using Artificial Neural Networks","volume":"20","author":"Gardner","year":"2020","journal-title":"IEEE Sens. J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"4104","DOI":"10.1109\/JSEN.2019.2961948","article-title":"High Sensitivity and Wide Dynamic Range Thermoresistive Micro Calorimetric Flow Sensor with CMOS MEMS Technology","volume":"20","author":"Xu","year":"2020","journal-title":"IEEE Sens. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"954","DOI":"10.1109\/JMEMS.2016.2596282","article-title":"Theoretical and Experimental Investigations of Thermoresistive Micro Calorimetric Flow Sensors Fabricated by CMOS MEMS Technology","volume":"25","author":"Xu","year":"2016","journal-title":"J. Microelectromechanical Syst."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"182","DOI":"10.1016\/j.sna.2006.03.021","article-title":"Effects of gas type on the sensitivity and transition pressure of integrated thermal flow sensors","volume":"132","author":"Bruschi","year":"2006","journal-title":"Sens. Actuators A Phys."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"414","DOI":"10.1016\/j.snb.2006.04.107","article-title":"Microfabricated thermal conductivity detector for the micro-ChemLab (TM)","volume":"121","author":"Cruz","year":"2007","journal-title":"Sens. Actuat B-Chem"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"611","DOI":"10.1007\/s40843-018-9389-0","article-title":"Recent advances in micro detectors for micro gas chromatography","volume":"62","author":"Qu","year":"2019","journal-title":"Sci. China Mater."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"936","DOI":"10.1016\/j.snb.2011.09.006","article-title":"Design, modeling, microfabrication and characterization of novel micro thermal conductivity detector","volume":"160","author":"Sun","year":"2011","journal-title":"Sens. Actuators B Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"15049","DOI":"10.1038\/micronano.2015.49","article-title":"A fully electronic microfabricated gas chromatograph with complementary capacitive detectors for indoor pollutants","volume":"2","author":"Qin","year":"2016","journal-title":"Microsyst. Nanoeng."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"127444","DOI":"10.1016\/j.snb.2019.127444","article-title":"Compact-GC platform: A flexible system integration strategy for a completely microsystems-based gas-chromatograph","volume":"305","author":"Zampolli","year":"2020","journal-title":"Sens. Actuators B Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1016\/j.sna.2016.08.019","article-title":"Micro thermal conductivity detector with flow compensation using a dual MEMS device","volume":"249","author":"Prouza","year":"2016","journal-title":"Sens. Actuators A Phys."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1016\/j.sna.2016.11.009","article-title":"Flow rate independent sensing of thermal conductivity in a gas stream by a thermal MEMS-sensor\u2014Simulation and experiments","volume":"253","author":"Hepp","year":"2017","journal-title":"Sens. Actuators A Phys."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1016\/j.sna.2017.08.011","article-title":"Multi-parameter monitoring of binary gas mixtures: Concentration and flow rate by DC excitation of thermal sensor arrays","volume":"265","author":"Hepp","year":"2017","journal-title":"Sens. Actuators A Phys."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/j.sna.2013.12.007","article-title":"A dynamic thermal flow sensor for simultaneous measurement of thermal conductivity and flow velocity of gases","volume":"208","author":"Cubukcu","year":"2014","journal-title":"Sens. Actuators A Phys."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1016\/j.sna.2013.08.025","article-title":"Simultaneous flow and thermal conductivity measurement of gases utilizing a calorimetric flow sensor","volume":"203","author":"Romero","year":"2013","journal-title":"Sens. Actuators A Phys."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1016\/j.sna.2011.04.002","article-title":"Temperature distribution on thermal conductivity detectors for flow rate insensitivity","volume":"167","author":"Kaanta","year":"2011","journal-title":"Sens. Actuators A Phys."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1088\/0960-1317\/21\/4\/045017","article-title":"Effect of forced convection on thermal distribution in micro thermal conductivity detectors","volume":"21","author":"Kaanta","year":"2011","journal-title":"J. Micromech. Microeng."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"095034","DOI":"10.1088\/0960-1317\/20\/9\/095034","article-title":"Novel device for calibration-free flow rate measurements in micro gas chromatographic systems","volume":"20","author":"Kaanta","year":"2010","journal-title":"J. Micromech. Microeng."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"6281","DOI":"10.1109\/TII.2019.2963683","article-title":"A Characterization of the Performance of Gas Sensor Based on Heater in Different Gas Flow Rate Environments","volume":"16","author":"Dong","year":"2020","journal-title":"IEEE Trans. Ind. Inform."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1088\/0960-1317\/11\/4\/304","article-title":"Micromachined structures for thermal measurements of fluid and flow parameters","volume":"11","author":"Wiegerink","year":"2001","journal-title":"J. Micromech. Microeng."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Kreith, F., Bohn, M., and Kirkpatrick, A. (1997). Principles of Heat Transfer, PWS Publishing Company.","DOI":"10.1115\/1.2887901"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"025001","DOI":"10.1063\/1.4789526","article-title":"A micro gas chromatography column with a micro thermal conductivity detector for volatile organic compound analysis","volume":"84","author":"Sun","year":"2013","journal-title":"Rev. Sci. Instrum."},{"key":"ref_36","unstructured":"Lide, D.R. (2016). CRC Handbook of Chemistry and Physics, CRC Press."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/4\/1308\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:16:45Z","timestamp":1760134605000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/4\/1308"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,2,9]]},"references-count":36,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2022,2]]}},"alternative-id":["s22041308"],"URL":"https:\/\/doi.org\/10.3390\/s22041308","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,2,9]]}}}