Development of High Frequency Virtual Thermocouples

Shengqi Lu, Purdue University


This thesis is dedicated in development of temperature measurement technique based on K-type thermocouple. Assessment of thermocouple response is conducted with the assistance of complete conjugate heat transfer simulations. Numerical results are acquired from an instantaneous solution of heat transfer between the interface of fluid and solid. Enormous CFD cases are analyzed with variations of gas temperature, gas pressure and wall temperature for a series of thermocouples at 6µm,12µm,25µm, and 50µm. The second-order transfer function is used to characterize the properties of response curves in discrete-time domain. Effect of the different parameters to thermocouple response is concluded in terms of correlations with respect to gas temperature, Re and wall temperature. Compensation strategies are developed to fulfill the goal of frequency enhancement. Finally, a high-frequency virtual thermocouple can be created from the responses of two thermocouples with relatively large diameters. And transient tests are conducted to verify the compensation method based on 25µm ,50µm, and 75µm thermocouples. In application, this thesis presents work suitable and beneficial for transient tests in short-duration facilities.




Paniagua, Purdue University.

Subject Area

Fluid mechanics

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