Pulse Heated Thermistor Device
Document Type
Creative works or constructive object presentation
Campus where you would like to present
Ellensburg
Event Website
https://digitalcommons.cwu.edu/source
Start Date
16-5-2021
End Date
22-5-2021
Keywords
Thermistor, Conductivity, Pulse-Decay
Abstract
Currently, there are several ways in which thermal conductivity can be calculated or assessed on a given material. However, with each method of testing comes potential limitations such as size, material state, complexity, and time. The goal of this study was to develop a pulse heated thermistor that would reduce all four limitations, thus provide precise and timely results regardless of the material state and size. A thermistor is resistor which changes resistance in accordance to temperature. To achieve the design, heat transfer and electrical methods were applied. As with all resistors, heat is dissipated across the element and released into the surrounding environment. With this idea, the thermistor can be introduced with a large voltage, causing its resistive element to overheat and thus reduce its resistance. To manufacture such a device insulative material was added to prevent heat dissipation in the wrong direction. To achieve precise results, test specimens were required to be prepared to reduce the effects of ambient convective heat transfer. Measurement times after pulse were shown to have best results after seven seconds due to the thermistor achieving a steady decay of temperature back to equilibrium. Water was observed to have a thermal conductivity value of 0.613 W/m-K, within 5% of its accepted value. The results were obtained within five minutes, exceeding the fifteen-minute requirement. With the results obtained, it is conclusive that the device is functional and precise.
Recommended Citation
Schrenk, Matthew, "Pulse Heated Thermistor Device" (2021). Symposium Of University Research and Creative Expression (SOURCE). 34.
https://digitalcommons.cwu.edu/source/2021/CEPS/34
Department/Program
Engineering Technologies, Safety, and Construction
Additional Mentoring Department
https://cwu.studentopportunitycenter.com/pulse-heated-thermistor-device/
Pulse Heated Thermistor Device
Ellensburg
Currently, there are several ways in which thermal conductivity can be calculated or assessed on a given material. However, with each method of testing comes potential limitations such as size, material state, complexity, and time. The goal of this study was to develop a pulse heated thermistor that would reduce all four limitations, thus provide precise and timely results regardless of the material state and size. A thermistor is resistor which changes resistance in accordance to temperature. To achieve the design, heat transfer and electrical methods were applied. As with all resistors, heat is dissipated across the element and released into the surrounding environment. With this idea, the thermistor can be introduced with a large voltage, causing its resistive element to overheat and thus reduce its resistance. To manufacture such a device insulative material was added to prevent heat dissipation in the wrong direction. To achieve precise results, test specimens were required to be prepared to reduce the effects of ambient convective heat transfer. Measurement times after pulse were shown to have best results after seven seconds due to the thermistor achieving a steady decay of temperature back to equilibrium. Water was observed to have a thermal conductivity value of 0.613 W/m-K, within 5% of its accepted value. The results were obtained within five minutes, exceeding the fifteen-minute requirement. With the results obtained, it is conclusive that the device is functional and precise.
https://digitalcommons.cwu.edu/source/2021/CEPS/34
Faculty Mentor(s)
John Choi and Charles Pringle