The heat transfer coefficient of external heat exchanger is key parameters for designing large-capacity circulating fluidized bed(CFB)boiler.In order to measure heat transfer coefficient in external heat exchanger of the CFB boiler

the measurement of heat transfer coefficient in the external heat exchanger was performed on a hot test facility with heating power of 4 MW.The effect of bed temperature and fluidized velocity on heat transfer characteristics was investigated. Through regression analysis on the test data

the correlation formula of heat transfer coefficient in external heat exchanger was obtained.The error between the heat transfer coefficient's calculated value and measured value was less than 14%

indicating the correlation equation has high calculation accuracy and can be applied in design calculation for CFB boilers.