Transient Characteristics of Unconfined Fire-Plume-Driven Ceiling Jets

摘要

An instrumentation system to measure temperatures and velocities in ceiling jets has been constructed. This system employs thermocouples to measure both temperatures and velocities at eight locations from the ceiling simultaneously. In this way, velocity and temperature profiles can be obtained in the ceiling jet as a function of time. The velocities are obtained by using pairs of thermocouples, one located downstream of the other, and cross correlating their temperature-time records to obtain the length of time that it takes for fluid to flow from one thermocouple to the other. Preliminary results indicate that the system works well; measurements made thus far compare favorably with steady-state data in the literature. Calibration work on the instrument is continuing and further transient ceiling jet measurements will be obtained.