坑道口部核化灰尘隔离阻断系统设计与研究

发布时间：2018-08-11 11:48

【摘要】：随着世界各国对核事故危害的重视,其对核事故的防护研究也越加深入,但是国内目前对于人防坑道对核化灰尘的防护研究甚少。本文将喷雾除尘的技术应用于坑道口部,设计一套隔离阻断系统,将核化灰尘阻隔在坑道口部之外,实现对坑道内部人员及装备的防护。本文主要从以下几方面开展研究工作。 (1)通过对惯性碰撞和截获捕集的分析,探讨了喷雾降尘机理；分析了影响喷雾降尘效率的主要因素,包括水雾粒径、雾化均匀度、单位体积内水雾颗粒数量以及水雾颗粒的运动速度；比较直射式雾化、旋转式雾化和离心式雾化等三种雾化方式,选取适合本文的雾化方式。 (2)隔离阻断系统中最关键的部分为喷头的设计。喷头设计需要计算的关键尺寸为喷嘴口径、收缩角及内腔直径三个变量,本文主要通过FLUENT仿真进行尺寸计算。在对某一变量进行仿真计算时,其他两个变量设定为固定值。通过FLUENT仿真计算出喷嘴各部分尺寸,使喷嘴在2MPa的工作压力下喷射速度最大,喷射角满足要求。 (3)通过FLUENT多项流模型模拟喷嘴喷射的水雾对核化灰尘的沉降情况。首先模拟核化灰尘以5m/s初速度进入坑道,计算出其在重力的作用下的自然沉降,核化灰尘在坑道内的最远飘散距离。使用隔离阻断系统进行喷雾降尘,重新通过FLUENT模拟得出核化灰尘的飘散距离,比较隔离阻断对核化灰尘的沉降效果。 (4)设计一个试验系统进行隔离阻断效果试验。通过试验测量单排喷头对核化灰尘的沉降效率,如果单排喷头阻隔效率不能高于85%,则将单排喷头改为双排喷头,再进行隔离阻断试验,直至阻隔效率达到85%。
[Abstract]:With the attention of countries in the world to the damage of nuclear accidents, the research on the protection of nuclear accidents is more and more in-depth, but there is little research on the protection of nuclear dust in civil air defense tunnels at present. In this paper, the technology of spray dust removal is applied to the entrance of the tunnel, and a set of isolation and blocking system is designed. The nuclear dust is blocked outside the entrance of the tunnel to protect the personnel and equipment inside the tunnel. The main work of this paper is as follows: (1) through the analysis of inertial collision and interception, the mechanism of spray dust reduction is discussed, and the main factors affecting the efficiency of spray dust reduction, including the particle size of water mist, are analyzed. The atomization uniformity, the number of water mist particles per unit volume and the moving speed of water mist particles are compared among the three atomization modes: direct atomization, rotary atomization and centrifugal atomization. The suitable atomization method is selected. (2) the most important part of the isolation and blocking system is the design of the nozzle. The key dimensions to be calculated for nozzle design are nozzle caliber, shrinkage angle and inner cavity diameter. This paper mainly calculates the dimensions by FLUENT simulation. When a certain variable is simulated, the other two variables are set to a fixed value. The size of each part of the nozzle is calculated by FLUENT simulation, which makes the jet speed maximum under the working pressure of 2MPa, and the injection angle meets the requirements. (3) the sedimentation of the jet water mist on the nucleated dust is simulated by the FLUENT multi-flow model. Firstly, the natural deposition of the nucleated dust under the action of gravity was calculated at the initial velocity of 5m/s, and the farthest distance of the nucleated dust in the tunnel was calculated. Using the isolation blocking system to spray dust, the dispersion distance of the nuclear dust was obtained by FLUENT simulation, and the effect of the isolation blocking on the deposition of the nuclear dust was compared. (4) A test system was designed to test the isolation blocking effect. The sedimentation efficiency of single row nozzle on nuclear dust was measured by experiment. If the barrier efficiency of single row nozzle is not higher than 85%, the single row nozzle should be changed into double row nozzle, and then the isolation blocking test will be carried out until the barrier efficiency reaches 85%.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU897;TL7

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