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Behavior of Bare and Aspirated Thermocouples in Compartment Fires.

pdf icon Behavior of Bare and Aspirated Thermocouples in Compartment Fires. (156 K)
Blevins, L. G.


National Heat Transfer Conference, 33rd. Proceedings. HTD99-280. August 15-17, 1999, Albuquerque, NM, 1999.


compartment fires; thermocouples; temperature measurements; instruments; room fires


As part of an effort to characterize the uncertainties associated with temperature measurements in fire environments, models of bare bead, single-shielded aspirated, and double-shielded aspirated thermocouples were developed and used to study the expected effects of varying the gas and average effective surroundings temperatures on the percent error in measured temperature of each type of thermocouple. The models indicate that thermocouples respond differently to changes in effective surroundings temperature in a hot upper layer than in a relatively cooler lower layer of a room fire. The use of an aspirated thermocouple reduces the error in the measurement, but does not eliminate it entirely. The present study is intended to provide fire researchers with a methodology for developing working models of thermocouples which are tailored to their own configurations.