低压电缆光交联辐照箱热流场实验研究与数值模拟

发布时间：2018-03-03 06:08

本文选题：数值模拟　切入点：流速实验　出处：《哈尔滨理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：电线电缆在经济建设和日常生活中扮演着重要角色，交联聚乙烯电缆已成为我国电力电缆中需求最大的品种。聚乙烯绝缘交联改性后，综合性能显著提高，广泛应用于电力电缆、控制电缆、计算机电缆等领域。紫外光交联技术由我国独立研发，拥有自主知识产权，是近年来开始应用于聚烯烃交联的方法，设备投资少、维护简便、节能高效，具有广阔的应用前景。辐照箱是光交联生产线中的核心设备，是完成光交联反应的场所，辐照箱内部的温度控制，是保证光交联反应顺利高效进行的关键。在辐照箱内部，利用空气强制对流换热带走高温壁面的热量，不仅需要降低部件温度，还必须保证冷却均匀，某些部件既不能过热也不能过冷，辐照箱通风方案的设计必须同时满足不同部分的温控要求。首先，进行辐照箱通风管道风速测量实验，利用热线风速仪测量空气流速，并记通风机的电动机转动频率，获得两种辐照箱通风结构在不同工况条件下的通风管道风速值。管道平均流速数据可为辐照箱流场数值模拟提供边界条件。其次，，建立低压电缆紫外交联辐照箱三种通风方案物理模型，利用FLUENT软件模拟冷却空气速度和压力分布，分析结构变化对设备流场的影响，特别关注绝缘层、紫外汞灯、反光罩的对流冷却效果。获得实验条件下难以测量的流场物理量，通过不同通风方案的流场数据对比，为辐照箱通风方案优化设计提供参考。最后，利用FLUENT DO模型对低压电缆和高压电缆二维截面温度场进行非稳态数值模拟，对模型准确性进行了验证，分析电缆截面温度分布以及绝缘、内屏蔽、导体线芯的温度变化趋势。在低压电缆内，对流换热和辐射换热引起的绝缘层温度变化并不显著，而绝缘与导体之间的热传导对绝缘层内的温度分布起了主要作用。在高压电缆内，热辐射、对流换热和热传导共同影响了电缆横截面的温度分布。
[Abstract]:Wires and cables play an important role in economic construction and daily life. XLPE cables have become the most demanding variety of power cables in China. It is widely used in power cable, control cable, computer cable, etc. Ultraviolet light crosslinking technology has been developed independently in our country and has its own intellectual property rights. It is a method that has been applied to polyolefin crosslinking in recent years, with less investment in equipment and simple maintenance. The irradiation box is the core equipment in the photocrosslinking production line, the place where the photocrosslinking reaction is completed, and the temperature control inside the irradiation box. It is the key to ensure the smooth and efficient photocrosslinking reaction. In the radiation box, the air forced convection heat transfer to take away the heat from the high temperature wall, not only need to reduce the temperature of the components, but also must ensure that the cooling is uniform. Some parts can not be overheated or undercooled. The design of the ventilation scheme of the irradiation box must meet the temperature control requirements of different parts at the same time. First of all, the experiment of measuring the wind speed of the ventilation duct of the irradiation box is carried out, the air velocity is measured by the hot-wire anemometer, and the rotating frequency of the motor of the ventilator is recorded. The wind velocity values of two kinds of radiation box ventilation structures under different working conditions are obtained. The average velocity data of the duct can provide boundary conditions for the numerical simulation of the flow field of the radiation box. Secondly, the physical models of three ventilation schemes for ultraviolet crosslinked irradiation box of low-voltage cable are established. The distribution of cooling air velocity and pressure is simulated by FLUENT software, and the influence of structural changes on the flow field of the equipment is analyzed, especially the insulation layer and ultraviolet mercury lamp. The convection cooling effect of the reflector is obtained. The flow field physical quantities which are difficult to measure under the experimental conditions are obtained. The comparison of the flow field data of different ventilation schemes provides a reference for the optimization design of the radiation box ventilation scheme. Finally, FLUENT do model is used to simulate the two-dimensional cross-section temperature field of low-voltage cable and high-voltage cable. The accuracy of the model is verified. The temperature distribution of cable cross-section, insulation and internal shielding are analyzed. The temperature change trend of conductor core. In low-voltage cable, the temperature change of insulation layer caused by convection heat transfer and radiation heat transfer is not significant. The heat conduction between the insulation and conductor plays a major role in the temperature distribution in the insulation layer. In the high-voltage cable, heat radiation, convection heat transfer and heat conduction affect the temperature distribution of the cross-section of the cable.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TM246

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