ESTIMATION OF CONVECTIVE HEAT TRANSFER BETWEEN FLUID AND PARTICLE IN CONTINUOUS FLOW USING A REMOTE TEMPERATURE SENSOR

摘要

The convective heat transfer coefficient (h_(fp)) between fluid and particle in continuous tube flow was estimated using a temperature pill, a remote electronic temperature sensor which uses a quartz crystal as the temperature sensing element. The temperature history of a particle (with temperature pill mounted within) was monitored as it moved through a test section. A finite element algorithm was then used to back calculate h_(fp) from the time-temperature data. The value of h_(fp) ranged from 134 W/m~2K to 669 W/m~2K (Nu=3.6 to 17.3) over a fluid generalized Reynolds number range (restricted by experimental constraints) from 19 to 196.8. As expected, h_(fp) decreased with increasing carrier medium viscosity and increased with increasing flow rates. Even with several conservative factors at play, the lowest Nusselt number was greater than the 2.0 expected for a spherical panicle in a stagnant fluid. Potential applications of the technique include noninvasive measurement of the temperature (and h_(fp) values) of the panicles moving within a fluid stream in otherwise inaccessible locations.