流道因素对熔融物堆内滞留压力容器下封头外的冷却能力影响试验研究
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摘要
流道因素是熔融物堆内滞留压力容器下封头外的冷却(IVR-ERVC)能力的关键影响因素之一。在全高度非能动ERVC试验装置REPEC-II上,针对各种流线型流道的几何条件,研究不同流道形状、流道进出口阻力变化以及流道障碍物等因素对临界热通量(CHF)的敏感性影响。试验结果表明:下封头外壁面CHF随外壁面方位角增大而增大,且其增大趋势随增大而减缓;ERVC流道间隙变窄对靠近入口处一定范围内的CHF具有一定的增强作用;对于出口附近区域而言,增加间隙宽度有助于增强CHF,但影响十分有限;在一定范围内,ERVC流道进出口阻力增大将使得高角度区域CHF略有降低,而且达到CHF时对应的循环流量随进出口阻力增加而降低,出口阻力的影响更显著;在ERVC流道中加装向加热面凸起的障碍物,可增大当地CHF,但该效应是局部的,这一措施会导致附近区域CHF降低。
Flow channel configuration has been considered as one of the key factors that affect the cooling ability of IVR-ERVC.In this paper,a series of sensitivity tests have been carried out on the full height passive ERVC facility,REPEC-II,with various replaceable streamline flow channels,thereby to study the influences of such factors as channel geometry,local resistance of the ERVC channel inlet and exit,and protruding barrier installation etc.In conclusion,critical heat flux(CHF)limits the outer wall of lower head increase with the change of azimuth angle from 0°to 90°,and the increasing trend slows down in the upper region(high azimuth angle region).As for the impact of narrowing the channel gap from the present design to a certain range,it is found that this,to an extent,helps enhance CHF within a distance to the inlet,while in the upper region the CHF enhanced effect seems rather limited.Meanwhile,it is observed that CHF in the upper region is slightly lowered when the flow resistance is made higher for both the inlet and exit,and thereby the corresponding circulation flow rate also drops.Influence of local flow resistance on CHF and circulation flow rate is found more obvious for the exit.In addition,installation of the pointed protruding barrier on the thermal insulation baffle may lead to the enhancement of local CHF due to its "guiding-mixing" effect.However,CHF near the enhancing region is observed somewhat lower.
Flow channel configuration has been considered as one of the key factors that affect the cooling ability of IVR-ERVC.In this paper,a series of sensitivity tests have been carried out on the full height passive ERVC facility,REPEC-II,with various replaceable streamline flow channels,thereby to study the influences of such factors as channel geometry,local resistance of the ERVC channel inlet and exit,and protruding barrier installation etc.In conclusion,critical heat flux(CHF)limits the outer wall of lower head increase with the change of azimuth angle from 0°to 90°,and the increasing trend slows down in the upper region(high azimuth angle region).As for the impact of narrowing the channel gap from the present design to a certain range,it is found that this,to an extent,helps enhance CHF within a distance to the inlet,while in the upper region the CHF enhanced effect seems rather limited.Meanwhile,it is observed that CHF in the upper region is slightly lowered when the flow resistance is made higher for both the inlet and exit,and thereby the corresponding circulation flow rate also drops.Influence of local flow resistance on CHF and circulation flow rate is found more obvious for the exit.In addition,installation of the pointed protruding barrier on the thermal insulation baffle may lead to the enhancement of local CHF due to its "guiding-mixing" effect.However,CHF near the enhancing region is observed somewhat lower.
引文
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[2]THEOFANOUS T G,J.P.Tu,T.Salmassi&T.N.Dinh.Quantification of limits to coolability in ULPU-2000configuration IV[J].Center for Risk Studies and Safety,University of California,Santa Barbara,CRSS-02.05.3,2003,23(05):230-235.
[3]THEOFANOUS T G,T.-N.D.Limits of Cool ability in the AP 1000-Related ULPU-2400Configuration V Facility[J].Center for Risk Studies and Safety,University of California,Santa Barbara,CRSS-03/06,2003,6(30):123-127.
[4]PARK R J,HA K S,KIM S B,et al.Two-phase natural circulation flow of air and water in a reactor cavity model under an external vessel cooling during a severe accident[J].Nuclear Engineering and Design,2006(23):2424-2430.
[5]HA K S,PARK R J,CHO Y R,et al.A Non-Heating Experimental Study on the Two-Phase Natural Circulation through the Annular Gap between Reactor Vessel and Insulation under External Vessel Cooling[C]//Icapp'04,June.2004.
[6]KA K H,PARK R J,KIM S B,et al.Flow analyses using RELAP5/MOD3code for OPR1000under the external reactor vessel cooling[J].Annals of Nuclear Energy,2006(11):966-974.
[7]ZHAO Y,ZHANG M,HOU F,et al.An experimental study of hypervapotron structure in external reactor vessel cooling[J].Nuclear Engineering and Design,2016,303:42-49.
[8]徐辉,匡波.一种表面开槽的ERVC增强措施可行性的实验研究[C]//中核核反应堆热工水力技术重点实验室,2016.
[9]郭宁.IVR-ERVC全尺寸下封头外壁临界热通量和流道流动试验初步研究[D].上海交通大学,2013.