Obtaining accurate temperature measurements in flame environments with thermocouples is extremely challenging due to the effects of radiative heat loss. These losses are difficult to quantify and often cannot be corrected for or minimized without sacrificing spatial resolution. In this work, a new experimental methodology is presented that has shown potential to minimize the temperature correction by both increasing and controlling the effects of convection. This is accomplished through high speed rotation of the thermocouple. The rotation yields a high and known convective velocity over the thermocouple. Heat transfer can then be modeled for the thermocouple, and a functional relationship between temperature and rotational speed can be found. Experiments were conducted over a range of rotational speeds in a control flame with a known temperature to test the feasibility of the rotating thermocouple (RTC) technique for temperature measurements in high temperature gases. The experimental results are shown to closely match the theory for the experimental gas temperature, over a range of rotational speeds, yielding extremely accurate gas temperature measurements. The results also demonstrate minimal perturbation to the flow field, even at high rotational speeds. Additionally, a deconvolution technique is proposed that would significantly enhance the spatial resolution of the technique.
","abstract_html":"<p>Obtaining accurate temperature measurements in flame environments with thermocouples is extremely challenging due to the effects of radiative heat loss. These losses are difficult to quantify and often cannot be corrected for or minimized without sacrificing spatial resolution. In this work, a new experimental methodology is presented that has shown potential to minimize the temperature correction by both increasing and controlling the effects of convection. This is accomplished through high speed rotation of the thermocouple. The rotation yields a high and known convective velocity over the thermocouple. Heat transfer can then be modeled for the thermocouple, and a functional relationship between temperature and rotational speed can be found. Experiments were conducted over a range of rotational speeds in a control flame with a known temperature to test the feasibility of the rotating thermocouple (RTC) technique for temperature measurements in high temperature gases. The experimental results are shown to closely match the theory for the experimental gas temperature, over a range of rotational speeds, yielding extremely accurate gas temperature measurements. The results also demonstrate minimal perturbation to the flow field, even at high rotational speeds. Additionally, a deconvolution technique is proposed that would significantly enhance the spatial resolution of the technique.</p>","abstract_has_math":false,"creators":["Krishnan, Siddharth"],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Thesis","degree_discipline":"Mechanical Engineering & Materials Science","degree_department":null,"school":null,"contributors":["Richard Louis Axelbaum","Benjamin Kumfer"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-05-15T07:00:00Z","date_published":"2014-05-15T07:00:00Z","updated_at":"2026-07-24T06:13:14Z","subjects":["Temperature measurement","thermocouple","radiation correction","Engineering","Mechanical Engineering"],"languages":["English (en)"],"rights":["I have not registered my thesis with the U.S. Copyright Office, and do not intend to."],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://openscholarship.wustl.edu/eng_etds/7"],"render_values":[{"text":"https://openscholarship.wustl.edu/eng_etds/7","href":"https://openscholarship.wustl.edu/eng_etds/7","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.7936/K7HX19NT","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Richard Louis Axelbaum","Benjamin Kumfer"]},{"key":"dc:creator","label":"Author","values":["Krishnan, Siddharth"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2014-06-24T07:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering & Materials Science","McKelvey School of Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Temperature measurement","thermocouple","radiation correction","Engineering","Mechanical Engineering"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English (en)"]},{"key":"dc:rights","label":"Dc Rights","values":["I have not registered my thesis with the U.S. Copyright Office, and do not intend to."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://doi.org/10.7936/K7HX19NT","https://openscholarship.wustl.edu/eng_etds/7"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Permanent URL: https://doi.org/10.7936/K7HX19NT"]},{"key":"dc:description.abstract","label":"Abstract","values":["Obtaining accurate temperature measurements in flame environments with thermocouples is extremely challenging due to the effects of radiative heat loss. These losses are difficult to quantify and often cannot be corrected for or minimized without sacrificing spatial resolution. In this work, a new experimental methodology is presented that has shown potential to minimize the temperature correction by both increasing and controlling the effects of convection. This is accomplished through high speed rotation of the thermocouple. The rotation yields a high and known convective velocity over the thermocouple. Heat transfer can then be modeled for the thermocouple, and a functional relationship between temperature and rotational speed can be found. Experiments were conducted over a range of rotational speeds in a control flame with a known temperature to test the feasibility of the rotating thermocouple (RTC) technique for temperature measurements in high temperature gases. The experimental results are shown to closely match the theory for the experimental gas temperature, over a range of rotational speeds, yielding extremely accurate gas temperature measurements. The results also demonstrate minimal perturbation to the flow field, even at high rotational speeds. Additionally, a deconvolution technique is proposed that would significantly enhance the spatial resolution of the technique.
"]},{"key":"dc:title","label":"Title","values":["An Approach to Thermocouple Temperature Measurements that Reduces Uncertainties Associated with Radiative Corrections"]}]}],"canonical_facts":{"dc:contributor":["Richard Louis Axelbaum","Benjamin Kumfer"],"dc:creator":["Krishnan, Siddharth"],"dc:date.available":["2014-06-24T07:00:00Z"],"dc:description":["Permanent URL: https://doi.org/10.7936/K7HX19NT"],"dc:description.abstract":["Obtaining accurate temperature measurements in flame environments with thermocouples is extremely challenging due to the effects of radiative heat loss. These losses are difficult to quantify and often cannot be corrected for or minimized without sacrificing spatial resolution. In this work, a new experimental methodology is presented that has shown potential to minimize the temperature correction by both increasing and controlling the effects of convection. This is accomplished through high speed rotation of the thermocouple. The rotation yields a high and known convective velocity over the thermocouple. Heat transfer can then be modeled for the thermocouple, and a functional relationship between temperature and rotational speed can be found. Experiments were conducted over a range of rotational speeds in a control flame with a known temperature to test the feasibility of the rotating thermocouple (RTC) technique for temperature measurements in high temperature gases. The experimental results are shown to closely match the theory for the experimental gas temperature, over a range of rotational speeds, yielding extremely accurate gas temperature measurements. The results also demonstrate minimal perturbation to the flow field, even at high rotational speeds. Additionally, a deconvolution technique is proposed that would significantly enhance the spatial resolution of the technique.
"],"dc:identifier":["https://doi.org/10.7936/K7HX19NT","https://openscholarship.wustl.edu/eng_etds/7"],"dc:language":["English (en)"],"dc:rights":["I have not registered my thesis with the U.S. Copyright Office, and do not intend to."],"dc:subject":["Temperature measurement","thermocouple","radiation correction","Engineering","Mechanical Engineering"],"dc:title":["An Approach to Thermocouple Temperature Measurements that Reduces Uncertainties Associated with Radiative Corrections"],"thesis:degree_discipline":["Mechanical Engineering & Materials Science","McKelvey School of Engineering"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T06:13:14Z"}