دانلود مقاله : A novel experimental technique to determine the heat transfer coefficient between t

چکیده : 

A novel method for directly measuring the temperature history of mobile hot ferromagnetic particles

(steel particles), substituting for reacting particles, in a binary-solid (reacting particles and inert particles)

downflow is introduced. The temperature history of the hot steel particles can be obtained by measuring

the temperature of the particles at different axial positions using magnetic fields that can separate the

steel particles from other bed materials immediately and easily. Employing the magnetic marking

method, magnetic sensors were used to detect the change in magnetic flux density in a given magnetic

field, and the residence time of the steel particles was also measured. The cross-sectional averaged particle-

to-bed heat transfer coefficients were calculated from the experimental results using simple heat

balance equations. The measured temperature data have a relatively wide error range; however, the average

temperature curves derived from the average particle-to-bed heat transfer coefficients agreed with

the temperature plots. Therefore, the experimental method of this study is applicable to the measurement

of the particle temperature in a binary-solid downflow. The results showed that there is strong correlation

between the particle-to-bed heat transfer coefficients and normalized collision frequency under

the laminar gas flow conditions