ESTIMATION of CONVECTIVE HEAT TRANSFER BETWEEN FLUID and PARTICLE IN CONTINUOUS FLOW USING A REMOTE TEMPERATURE SENSOR1

The convective heat transfer coefficient (hfp) 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 hfp from the time‐temperature data. the value of hfp ranged from 134 W/m2K to 669 W/m2K (Nu=3.6 to 17.3) over a fluid generalized Reynolds number range (restricted by experimental constraints) from 19 to 196.8. As expected, hfp 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 particle in a stagnant fluid. Potential applications of the technique include noninvasive measurement of the temperature (and hfp values) of the particles moving within a fluid stream in otherwise inaccessible locations.