【摘要】 提出了循环流化床锅炉Γ形导向风帽临界漏渣的理论判据,并搭建试验台,进行了验证试验。Γ形导向风帽临界漏渣的判据为,颗粒流倒灌进风帽内的动量流率与风帽喷出气体动量流率相等。试验中临界漏渣状态通过分别调节主床流化风量与布置于床外侧试验风帽的风量得到。测量试验风帽出口处的床内静压与风帽内静压差,用于计算颗粒流倒灌入风帽的流速和动量流率,同时测定试验风帽内气体流速以计算风帽喷出气体的动量流率。床料倒灌入风帽速度的计算中,还采用了颗粒拟流体的假设和单相流体管嘴出流模型。试验比较了多组临界漏渣状态下两股动量流率的大小,结果表明,临界漏渣状态下,两者的动量流率确实接近相等。又从风帽临界漏渣力学方程得到了风帽临界出口风速与运行床压的关联式。据此得出的实炉运行床压下风帽临界漏渣风速与现有经验设计相符。提出的风帽临界漏渣判据及其风帽临界速度式对于循环流化床导向风帽参数设计具有工程指导意义。更多还原

【Abstract】 A theoretical criteria for critical condition of backflow inΓ-type nozzle in CFB boiler has been built,also test-bed has been put up to carry out test.Critical condition of backflow inΓ-type nozzle is:momentum flow rate of the particles flow into the nozzle is equal to exhaust gas momentum flow rate of nozzle.Critical points in test are obtained through regulation of fluidized air volume in the main bed and the air flow in the lateral test nozzle.Test measurement is static pressure difference between the bed and inside the nozzle,which is used to calculate the particle velocity and momentum flow rate,at the same time,measurement of gas flow rate in external nozzle is used to calculate momentum flow rate of exhaust gas in the nozzle.in the calculation of particle flow rate backward the nozzle, based on the assumption that the particles are similar to fluid,introduction of formula of nozzle outflow for single-phase fluid is used to caculate speed of bed material backflowing into the nozzle in this article.Comparing the size of two momentum flow rates of various test groups in critical backflow state,the result shows that when the test is in a critical state of material backflow,both of the momentum flow rates are indeed close to the same.from the mechanics equation of critical backflow in nozzle correlation between critical backflow air speed and operating bed pressure has been obtained.Critical backflow air speed calculated is in line with the existing design experience.Theoretical criteria for critical condition of backflow and correlation of critical backflow air speed can guide the project concerning design parameters of CFB nozzle.更多还原