SGER: Rate-Based Sensor Development for Advancing Heat Transfer Measurements

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

ABSTRACT Proposal Number: CTS-0601236 Principal Investigator: Frankel, Jay Affiliation: University of Tennessee-Knoxville Proposal Title: SGER: Rate-Based Sensor Development for Advancing Heat Transfer Measurements The objective of this Small Grant for Exploratory Research is to develop, validate, and demonstrate an accurate, universal voltage rate sensor interface that accurately recovers the instantaneous heating/cooling rate, dT/dt. Upon appropriate calibration, this sensor interface would allow real-time extraction of rates associated with many physical quantities of interest (e.g., temperature, heat flux, concentration, strain, stress, pressure, intensity, etc.). In many applications such as in the energy, aerospace, fire metrology, security and defense sectors, rate information is crucial for reaching fast and reliable diagnosis, prediction and control. Intellectual Merit: The frequency response of the differentiation process will produce an output in proportion to the signal frequency. Therefore, upon direct differentiation, noise and errors prevalent in all measurements will increase relative to the signal and deteriorate the signal/noise ratio, even after painstaking smoothing/ filtering. This is the current state of determining rate quantities, and it is not acceptable. This project will support a multi-disciplinary team that will utilize experimental and theoretical heat transfer techniques, experimental and theoretical design circuit analysis, and mathematical analysis and computation, with the goal of obtaining accurate estimates for surface heat fluxes based on surface or embedded temperature sensors. Rate information typically has low frequency spectrum, especially when the sensor is attached in an embedded solid medium. The specific goals of the project are: (1) Theoretically establish that temperature and heat flux rate measurements can be directly implemented into a sensor system, and identify the feasibility of a universal solution with an interface module to convert voltage output from sensors to voltage rate; (2) Develop instrumentation strategies including amplitude modulation (which will allow up-converting signal spectra such that S/N ratio of the derivatives will remain manageable); and RC circuitry / amplification and filtering strategies (that will circumvent the difficulties associated with the frequency response of signal differentiation); (3) Develop a series of heat transfer experiments for validation purposes and to study implementation issues addressing real-world practices. Broader Impacts: Success of the proposed research will impact aerospace, energy, fire, geophysical and seismic sciences, health care, engineering sciences, defense, and national security applications. Moreover, rate sensors would have numerous utilities in improving manufacturing processes that require thermal control. As voltage signals are commonly adopted for sensor outputs, this interface module can be used with a number of sensors to extract rate-information. The multidisciplinary nature of the project permits a novel and highly positive addition into the existing educational programs on campus. The research findings will be incorporated into undergraduate course materials to expose students to interdisciplinary research. As means for promoting graduate studies, advanced training of undergraduates will be requested with REU supplements. Many of the results can be incorporated into both the mechanical and electrical engineering undergraduate laboratories.