塑料管车间内自然对流研究

以生产产品和循环水箱工作情况下塑料管车间内自然对流传热为研究对象,采用计算流体力学、传热学理论进行数值计算,研究了Ra在103～107之间时,车间内流体流线、等温线的分布特征和变化和产品温度梯度。研究结果表明:随着Ra的增大,厂房内的热传输形式由热传导逐渐向对流传热转换;靠近产品处空气的温度梯度要大于中央区域等温线的温度梯度;空气在靠近产品处向上移动,靠近墙壁处向下移动,以产品为界分成顺时针、逆时针两个漩涡,小漩涡流速大于大漩涡;产品处温度梯度总是大于其他区域,循环水箱在侧面时产品温度梯度总是小于在中间情况;在存在自然对流现象的车间内,低品位剩余热量(循环水箱释放热量)可以改变车间内的温度和空气流动状态,是一部分可以利用的能源。

RESEARCH ON NATURAL CONVECTION IN PLASTIC PIPE WORKSHOP

The research object is the natural convection heat transfer in plastic pipe workshop in the situation of producing and circulating tank working.This paper uses CFD theory and heat transfer theory to make numerical calculation,researches the distribution and variation of streamline and isotherm in workshop,and the product’s temperature gradient with Ra among 103~106.The research results indicate that when increasing Ra,the heat transfer form changes gradually from thermal conductivity to convective heat transfer,the temperature gradient near the product is greater than that in the central area.The air moves up near the product and moves down near the wall,and is divided into two vortexs by the product,one clockwise and the other anticlockwise.The flow velocity of small vortex is higher than big vortex.The temperature gradient near product is always greater than in other areas,and it’s smaller when the circulating tank is on one side compared with the middle position.In the workshop where natural convection exists,low grade surplus heat(which releases by circulating tank)can change the temperature and the air flow condition in the workshop.This is a part of utilizable energy.