CAJ | 학술논문

为了研究起伏运动对自然循环流动特性的影响，针对以5 MW低温核供热堆（ NHR）为基础建立的自然循环试验回路，自行开发计算程序研究起伏强度和周期对自然循环流动波动、加热段出口过冷度以及换热器二次侧出口过冷度的影响。建立数学模型，坐标系固定于试验本体上，采用流体相对速度，将起伏条件下自然循环问题转化为非惯性参考系问题，考虑起伏运动引入附加力对自然循环的影响，在重力g的前面乘一个随时间变化的系数（1－k· sin（ωdt ））。计算结果表明：起伏强度k越大，流量和温度波动越大；起伏周期T越大，流量波动越大且呈现出明显的非线性波动，大周期的起伏运动可能造成加热段出口出现饱和甚至沸腾的情况。对起伏运动影响自然循环机理的分析表明：起伏引入的附加作用力和重力一起构成一个交变力场，在有密度差的情况下形成自然循环驱动力，从而引起自然循环流动。
위료연구기복운동대자연순배류동특성적영향，침대이5 MW저온핵공열퇴（ NHR）위기출건립적자연순배시험회로，자행개발계산정서연구기복강도화주기대자연순배류동파동、가열단출구과랭도이급환열기이차측출구과랭도적영향。건립수학모형，좌표계고정우시험본체상，채용류체상대속도，장기복조건하자연순배문제전화위비관성삼고계문제，고필기복운동인입부가력대자연순배적영향，재중력g적전면승일개수시간변화적계수（1－k· sin（ωdt ））。계산결과표명：기복강도k월대，류량화온도파동월대；기복주기T월대，류량파동월대차정현출명현적비선성파동，대주기적기복운동가능조성가열단출구출현포화심지비등적정황。대기복운동영향자연순배궤리적분석표명：기복인입적부가작용력화중력일기구성일개교변력장，재유밀도차적정황하형성자연순배구동력，종이인기자연순배류동。
In order to investigate the effect of heaving motion on the flow characteristics of natural circulation, a cal-culation program was developed to study the influence of heaving strength and heaving cycle on the flow fluctuation of natural circulation, undercooling in the outlet of heating section and undercooling in the outlet of the secondary side of heat exchanger based on a natural circulation loop of 5MW experimental low temperature nuclear heating reactor ( NHR) .A mathematical model was established and the coordinate system was mounted on the experimental appara-tus. The issue of natural circulation under heaving condition could be treated as a problem in non-inertial reference frame.Considering the effect of an additional force resulting from heaving motion on natural circulation, a time-de-pendent coefficient (1-ksin(ωd t) ) was multiplied with gravity acceleration g.Calculation results indicated:higher level of heaving strength would lead to more serious fluctuation of flow and temperature;flow fluctuation exhibited an obvious nonlinear property and long-periodic heaving motion would result in saturation or even boiling.The analysis of the influence mechanism of heaving motion on natural circulation showed an alternating field composed of the addi-tional force and gravity, forming the driving force of natural circulation in case of flow density contrast.