The smooth countercurrent of gas and liquid phases in the hot leg of pressurized water reactor(PWR)is very important to prevent the core melting accident,and the hot leg is composed of horizontal pipe and inclined pipe.In order to determine the constraint mechanism of gas-liquid countercurrent in the hot leg,experiments were carried out on the characteristics of countercurrent flow limitation(CCFL)in inclined and horizontal pipes with ambient air/water as two-phase working medium,and the effects of pipe layout inclination angle(0°～30°)and pipe diameter(40～100 mm)on CCFL in the pipes were studied.The main conclusions are as follows:under the CCFL conditions,the flow pattern in the horizontal pipe shows a typical stratified flow;in the inclined pipe,as the inclination angle and diameter of the pipe increase,stratified flow gradually transits to mist flow.At the same pipe diameter,the CCFL curve characterized by superficial velocities increases with the increase of pipe inclination,which indicates that the gas-liquid countercurrent flow in the hot leg is mainly controlled by the horizontal section.At the same pipe inclination angle,the CCFL curves for both inclined and horizontal pipes increase with the increase of pipe diameter.The conventional Wallis parameters do not reflect the effect of pipe inclination on the CCFL,and also fail to accurately characterize the effect of pipe diameter on the CCFL of horizontal pipes;however,they can correlate the effect of pipe diameter on the CCFL of inclined pipes satisfactorily.Finally,an experimental correlation,which can simultaneously correlate the effects of pipe inclination and diameter,was proposed for the CCFL of inclined pipes.The research results provide basic data and experimental correlation for the safety analysis of PWR nuclear power plant.
Pressurized water reactorLoss of coolant accidentCCFLInclined pipeDiameter effect
万方数据
维普
