Experimental Study On Fluidizing, Pulsating & Heat Transfer Characteristics Of A Rijke-type Self-pulsating Fluidized Bed

The thesis proved the concept of Self-pulsating Fluidized Bed and studied the fluidized, pulsating and heat transfer characteristic of a Rijke-type Self-pulsating Fluidized Bed experimentally. It mainly includes the five parts as following:(1) References on pulsating combustion technology were reviewed. Based on discussion of the characteristics of fluidized combustion technology and pulsating combustion technology, a novel concept Self-pulsating Fluidized Bed which combining both techniques' advantages was brought forward.(2) As a research base, a Rijke tube pulsating combustor test rig was built. The pulsating and heat transfer characteristics of the Rijke tube were tested. The effects of heat release intensity and the heat source temperature on inspirng the pulsating frequency and intensity of Rijke tube were investigated. It was concluded that the pulsating would be stimulated more easily as the heat release intensity was higher, and the pulsating intensity was stronger as the heat source temperature was higher. The effect of pulsating on heat transfer was also measured.(3) A Rijke-type Self-pulsating Fluidized Bed test rig was designed and constructed. It was observed the bed material fluidized very well and the bed remained at a good fluidizing state with the inspired acoustic pulse when the bed operated at about 650℃ and the air velocity is below 1.8m/s. The concept of Self-pulsating Fluidized Bed was proved by a feasibale test.(4) The fluidizing and pulsating characteristics of the Rijke- type Self-pulsating Fluidized Bed was studied experimentally. The minumin iluidized velocity was obtained. With analyzing pressure signals along the tube by frequency time-domain and frequency-domain method, the pressure pulsating characteristics of the pulsating fluidized bed was obtained. The section also presented the effects of air velocity and static bed height on the fundamental wave frequency, amplitude of the pressure pulse, the fundamental wave acoustic frequency and the sound pressure level of the acoustic pulse. And it was confirmed that the main operation conditions of this Self-pulsating Fluidized Bed were higher combustion temperature, lower air velocity which insured fluidizing adequately and lower static bed height.(5) Heat transfer characteristics of the Rijke- type Self-pulsating Fluidized Bed at were researched by experiments at four different states. The influences of the air velocity, pulsating intensity and static bed height to the heat transfer coefficient were studied. The experiment results indicates that the heat transfer of the combustor was enhanced strongly when the pulse occurd. It was found the heat transfer coefficient of the Pulsating Fluidized Bed was the highest and its values were 10%~20% higher than a Rijke tube and a fluidized bed. The research gave the optimal operation state of the Rijke- type Self-pulsating Fluidized Bed.A special pressure measurement system and a related software based on Lab VIEW were developed to measure the high frequency pressure signals in the research. This work helps solving the measurement problem of high frequency pressure singals in the Rijke- type Self-pulsating Fluidized Bed successfully.