本文選題：自然循環(huán)　切入點：流動特性　出處：《哈爾濱工程大學》2014年碩士論文

【摘要】：安全殼作為核電站最后一道屏障,可以在嚴重事故情況下承受事故產生的內壓力,防止放射性物質外泄。在新一代核電站中,非能動安全殼冷卻系統(tǒng)(PCCS)是防止安全殼在事故條件下超壓超溫受損的一項重要設施。PCCS系統(tǒng)利用自然循環(huán)的方式將熱量導出,自然循環(huán)流動特性影響著PCCS系統(tǒng)的安全運行,開展對自然循環(huán)流動特性的研究具有重要意義,因此,本文設計了 PCCS簡化系統(tǒng),以對PCCS的自然循環(huán)特性進行初步研究。在低壓、低含氣率條件下,對系統(tǒng)的自然循環(huán)啟動、穩(wěn)態(tài)運行時的流動特性進行了實驗研究。實驗表明自然循環(huán)系統(tǒng)在啟動運行過程中經(jīng)歷了三個階段一單相區(qū)、過渡區(qū)和穩(wěn)態(tài)運行區(qū);其中過渡區(qū)又可分為過渡一區(qū)和過渡二區(qū)。過渡一區(qū)內的流量振蕩是由間歇泉不穩(wěn)定引起的。過渡二區(qū)的流動不穩(wěn)定性在不同加熱功率下有不同的表現(xiàn)形態(tài):低加熱功率時,間歇泉不穩(wěn)定和閃蒸引發(fā)了流量振蕩;高加熱功率時,閃蒸和飽和沸騰引發(fā)了流量振蕩。穩(wěn)態(tài)運行時,系統(tǒng)內存在5種行為模式:周期性閃蒸伴隨噴泉、閃蒸伴隨周期性沸騰噴發(fā)、持續(xù)性閃蒸、周期性沸騰噴發(fā)和穩(wěn)定氣液兩相流動。研究表明,閃蒸和沸騰噴發(fā)是影響流動特性的兩個主要因素,兩者對流動主導作用權重的變化是流動模式隨功率發(fā)生演變的根本原因。實驗獲得的流動模式分布圖可為自然循環(huán)系統(tǒng)的運行提供參考。在考慮驅動壓頭、回路阻力、過冷沸騰、閃蒸和散熱的基礎上,建立了自然循環(huán)穩(wěn)態(tài)運行時平均流量的計算模型,計算結果和實驗值符合良好,表明用平均穩(wěn)態(tài)的流動代替不穩(wěn)定的流動來研究自然循環(huán)流動特性的思路是可行的。由該模型預測了高功率下自然循環(huán)平均流量的變化趨勢和流量靜態(tài)漂移,給出了系統(tǒng)由不穩(wěn)定流動過渡為穩(wěn)定氣液兩相流動的判斷標準和穩(wěn)定邊界的確定方法,分析了復雜實驗回路對自然循環(huán)平均流量及流量靜態(tài)漂移的影響。
[Abstract]:Containment, as the last barrier for nuclear power plants, can withstand the internal pressure caused by accidents in case of serious accidents and prevent the leakage of radioactive materials. In the new generation of nuclear power plants, Non-active containment cooling system (PCCSs) is an important facility to prevent the containment from being damaged by overpressure and overtemperature under the accident condition. The heat is derived by natural circulation. The characteristics of natural circulation flow affect the safe operation of the PCCS system. It is of great significance to study the characteristics of natural circulation flow. Therefore, a simplified PCCS system is designed to study the natural circulation characteristics of PCCS. Under the condition of low pressure and low gas content, the natural circulation of the system is started. The experimental results show that the natural circulation system has experienced three stages: single phase region, transition zone and steady operation area. The flow oscillation in the transition zone is caused by geysers instability. The flow instability in the transition zone has different forms under different heating power: when the heating power is low, the flow instability in the transition zone can be divided into two areas: when the heating power is low, the flow instability in the transition zone is caused by the instability of geysers. The instability and flash of geysers cause flow oscillations, while at high heating power, flash and saturated boiling trigger flow oscillations. Flash is accompanied by periodic boiling eruption, continuous flash eruption, periodic boiling eruption and stable gas-liquid two-phase flow. The change of the weight of the flow leading action is the fundamental reason for the evolution of the flow mode with power. The flow pattern distribution map obtained by the experiment can provide a reference for the operation of the natural circulation system. Considering the driving pressure head, the loop resistance, On the basis of subcooled boiling, flash evaporation and heat dissipation, the calculation model of average flow rate in steady state operation of natural circulation is established. The calculated results are in good agreement with the experimental data. The results show that it is feasible to use the average steady flow instead of the unstable flow to study the flow characteristics of the natural cycle. The model is used to predict the variation trend of the average flow rate and the static drift of the flow under the high power condition. The criterion of the system transition from unstable flow to stable gas-liquid two-phase flow and the method to determine the stable boundary are given. The influence of complex experimental loop on the natural circulation average flow and flow static drift is analyzed.
【學位授予單位】：哈爾濱工程大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM623;TL364.3

【參考文獻】

相關期刊論文 前10條

1 邢立淼;郭峗;曾和義;;基于RELAP5的單通道自然循環(huán)流動不穩(wěn)定性分析[J];原子能科學技術;2010年08期

2 譚思超;高璞珍;秦勝杰;黃彥平;蘇光輝;;低流速自然循環(huán)過冷沸騰汽泡脫離點實驗研究[J];核科學與工程;2008年04期

3 王建軍;楊星團;姜勝耀;;HRTL-5自然循環(huán)穩(wěn)態(tài)特性[J];原子能科學技術;2008年05期

4 王建軍;楊星團;姜勝耀;;低壓低干度自然循環(huán)流量漂移和熱虹吸現(xiàn)象的動態(tài)模擬[J];核動力工程;2007年01期

5 劉曉晶;匡波;陳宏;徐濟捚;王濤;孫德祥;蔣序倫;;兩相自然循環(huán)非線性特征及實驗研究[J];核動力工程;2006年S1期

6 譚思超;龐鳳閣;高璞珍;;低壓兩相自然循環(huán)流動不穩(wěn)定實驗研究[J];哈爾濱工程大學學報;2006年02期

7 匡波,陳宏,胡志華,徐濟捚;兩相自然循環(huán)系統(tǒng)靜態(tài)流量漂移及其實驗驗證[J];工程熱物理學報;2005年06期

8 楊瑞昌,王彥武,王飛,唐虹,施德強,魯鐘琪;自然循環(huán)過冷沸騰流動不穩(wěn)定性的實驗研究[J];核動力工程;2005年04期

9 譚思超,張紅巖,龐鳳閣,高璞珍;單相-兩相自然循環(huán)過渡點的實驗研究[J];哈爾濱工程大學學報;2005年03期

10 王世亨;;第四代核電站與中國核電的未來[J];科學;2005年01期

相關博士學位論文 前1條

1 張華;垂直管道低溫汽-液兩相流動彈狀流流型及動態(tài)特性的研究[D];上海交通大學;2009年

，

本文編號：1663882